Demography, Dispersal, and Migration of the Swallow-tailed Kite by Avian Research & Conservation Institute

Demography, Dispersal, and Migration

of the Swallow-tailed Kite

FINAL REPORT

Kenneth D. Meyer

December 2004

Florida Fish and Wildlife Conservation Commission

620 South Meridian Street

Tallahassee, FL 32399-1600

Demography, Dispersal, and Migration

of the Swallow-tailed Kite

Kenneth D. Meyer National Park Service, Big Cypress National Preserve

HCR 61 Box 110, Ochopee, Florida 34141

Present address: Avian Research and Conservation Institute

411 N.E. 7 Street, Gainesville, Florida 32601

Submitted as final report for

Florida Fish and Wildlife Conservation Commission

Project NG94-025

December 2004

This report is the result of a project supported by the Florida Fish and Wildlife Conservation Commissionâ&#x20AC;&#x2122;s Nongame Wildlife Trust Fund. It has been reviewed for clarity, style, and typographical errors, but has not received peer review. Any opinions or recommendations in this report are those of the authors and do not represent policy of the Commission.

Suggested citation: Meyer, K. D. 2004. Demography, dispersal, and migration of the swallowtailed kite. Final Report. Florida Fish and Wildlife Conservation Commission, Tallahassee, Florida, USA.

Demography, Dispersal, and Migration

of the Swallow-tailed Kite

Kenneth D. Meyer National Park Service, Big Cypress National Preserve, HCR 61 Box 110, Ochopee, Florida 34141

Present address: Avian Research and Conservation Institute, 411 NE 7 Street, Gainesville, Florida 32601

Abstract: Florida is the breeding-season stronghold of the northern subspecies of the swallow-tailed kite (Elanoides forficatus). This neotropical migrant once nested in 17, and perhaps as many as 21, states but suffered an abrupt decline at the turn of the century. The breeding distribution has changed little, if any, since the 1940s, when the population reached its low point. Estimates converge on 800–1,200 pairs, or about 3,500–5,000 individuals at the end of the breeding season. Florida harbors two-thirds of the remaining swallow-tailed kites, with sub-populations numbering no more than about 100–150 pairs in each of 6 other southeastern states. The Florida Fish and Wildlife Conservation Commission ranked the swallow-tailed kite as one of Florida’s most vulnerable and poorly understood species. Previous research by the project director indicated that loss and degradation of essential habitat in south-central and southwestern Florida, where most of the remaining kites nest and roost on privately owned land, combined with natural limiting factors and the species’ greatly reduced range place the swallow-tailed kite’s U.S. population at risk. The present study examined 3 high-priority topics: demography, post-breeding dispersal and staging behavior, and migration. It was the first attempt to investigate the biology and conservation needs of Florida’s swallow-tailed kites beyond the state, where this breeding population spends at least half its year. We found and monitored 159 nests (113 in southern Florida, 46 in northern peninsular Florida) from 1995 to 1997 and radio tagged and monitored 72 juveniles (52 in the south, 20 in the north) for 2 years after hatching. We examined the extent of dispersal, size of activity ranges, pre-migration staging behavior, and roost locations and attendance. Many juveniles dispersed widely during the pre-migration period, whereas others restricted their activity and movements to the general nest area. This difference may be related to sex. Kites in the former group typically used several roosts, including some of the largest ones previously found; juveniles with restricted ranges tended to use small roosts near their nesting neighborhoods. The radio-tagged kites also provided data on post-fledging survival (about 75% in each year), first-year survival (<20% were detected at 1 year old, although this may be explained by factors other than mortality), philopatry, age at first breeding (not prior to 2 years and probably not before 3), and subadult behavior. Six kites (4 breeding adults and 2 young of the year) fitted with satellite transmitters in 1996 revealed a well-defined migration corridor through Central and South America and a wintering destination in a relatively small area of Brazil. VHF radio–tagged juveniles from Florida and Louisiana associated with local breeding kites on the winter range and led to the discovery of 2 large communal roosts. We studied roost phenology and habitat associations and examined potential threats and relevant land-use issues throughout the winter range. We developed collaborative relationships with Latin American colleagues to investigate further the critical areas, habitat requirements, threats, opportunities for monitoring, and conservation needs of migrating and wintering swallow-tailed kites. The swallow-tailed kite’s predominant year-round dependence on privately owned lands is a central issue to the species’ conservation. It is essential that we develop management alternatives to acquisition of critical habitat, including conservation easements, cooperative management agreements, and landowner incentives. Rangewide threats to Florida’s population of swallow-tailed kites are difficult to identify and manage. The best long-term strategy for conservation is to continue investigating limiting factors and emerging threats, to determine where intervention can assert the most influence, and to plan management action accordingly.

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FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

ACKNOWLEDGMENTS I thank the staff of the National Park Service, Big Cypress National Preserve, and especially Ron Clark, Peg Kohl, and Deborah Jansen, and Ellen Hand for administrative, clerical, and logistic support; and the following for land access, sighting reports, nest locations, or accommodations: Nancy Douglass, Dwight Myers, Ski Clark, Victor Echavez, Dan Miller, Jeff Gore, Terry Doonan, Phil Manor, Vic Doig, Susan Cerulean, Pete Southall, Julie Hovis, and Jim Schortemeyer, Florida Fish and Wildlife Conservation Commission (FWC); Bill Robertson, John Ogden, and Bob Doren, National Park Service, Everglades National Park; Franklin Percival, Florida Cooperative Wildlife Research Unit; Larry Richardson, Catherine Dees, and Walter Taylor, U.S. Fish and Wildlife Service, Florida Panther National Wildlife Refuge; Joe Reinman, St. Marks National Wildlife Refuge; Ken Litzenberger, Lower Suwannee National Wildlife Refuge; Jane Monaghan, Carey Sekarak, and Susan Fitzgerald, U.S. Forest Service; Doria Gordon and Steve Morrison, The Nature Conservancy; Dave Leonard, Leslie Backus, and Reed Bowman, Archbold Biological Station; Charles Lykes Jr., Lykes Brothers Corporation; Bob Progulski, Paul Ebersbach, and Pat Walsh, Department of Defense, Avon Park Air Force Range; Peter Anderson, Linda Epperson, Wesley Jones, Sam Cole, Ann Harvey, Dan Pearson, Janet Yesch, and Ken Alvarez, Florida Department of Environmental Protection; John Douglas, Linda Douglas, Grant Hokit, and Brad Smith. I am especially grateful to John Arnett, Audrey Washburn, Tim Dellinger, Debra Duvall, Alex Kolker, and Aimee Roberson for their enthusiasm and dedication to careful fieldwork under difficult conditions. Tim Dellinger and Audrey Washburn did an excellent job climbing nest trees. Megan Parker, Vicky Dreitz, Gary Slater, and Leslie Backus also helped with climbing. Karen Dunne and Frank Ogborn provided safe and skillful piloting services. The following contributed to our work in Brazil: Ron Clark, Peg Kohl, Kim Kacer, Ellen Hand, Shannon Bouton, Marcy Rol, Peter Crawshaw, Iolita Bampi, Clovis Nobre de Miranda, Munir Nasr, and Cesar Marquez. John Arnett and Audrey Washburn did the fieldwork in Brazil in 1996 and 1997. I am grateful for their hard work and dedication, which made the project a success. I thank Brian Millsap, FWC, for sharing his insights on swallow-tailed kites; and David Cook, Stuart Cumberbatch, and Karen Lamonte, FWC, for their administrative support. Primary funding for the project came from FWCâ&#x20AC;&#x2122;s Nongame Wildlife Trust Fund, with additional contributions from the National Fish and Wildlife Foundation, the National Park Service at Big Cypress National Preserve, Disney Wildlife Conservation Fund, John Alden Insurance Company, Barbara Muschlitz, and Zach Neece.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

TABLE OF CONTENTS ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Prior Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Priorities for Further Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Scope of the Present Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Original Contract (Southern Florida) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Contract Amendment (Northern Florida) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Finding Nests and Radio Tagging Nestling Kites . . . . . . . . . . . . . . . . . . . . . . . . 6

Locating, Monitoring, and Collecting Demographic

Data on Radio-tagged Juveniles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Tracking Dispersing Kites; Locating, Monitoring, and

Estimating Productivity at Communal Roosts . . . . . . . . . . . . . . . . . . . . . . . . . 8

Satellite Radio Tagging and Tracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Migration Corridor and Critical Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Winter Range: Describing, Searching for VHF-tagged

Kites, Contacting Cooperators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

RESULTS AND DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Nest-finding and Radio Tagging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Range Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Roosts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Post-fledging Mortality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Survival . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Age of First Breeding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Behavior as Sub-adults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Migration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Presentations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

IMPLICATIONS FOR CONSERVATION AND MANAGEMENT . . . . . . . . . 56

LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

APPENDIX A. Movements of Juvenile Swallow-tailed Kites, 1996 . . . . . . . . . . 61

APPENDIX B. Movements of Juvenile Swallow-tailed Kites, 1997 . . . . . . . . . . 85

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

INTRODUCTION The northern subspecies of the swallow-tailed kite (Elanoides forficatus), which breeds in the southeastern United States and spends the boreal winter in South America (Cely 1979, Robertson 1988), once nested in 17 and perhaps as many as 21 states (Meyer 1995). The U.S. population (herein synonymous with northern subspecies) suffered an abrupt decline at the turn of the century, perhaps due to shooting and habitat loss (Robertson 1988). The breeding distribution has changed little, if any, since the 1940s, when the population reached its low point. At present, nesting occurs only in Florida and small portions of 6 other southeastern states. Estimates place the U.S. breeding population at 800–1,200 pairs, or, counting nonbreeding adults and young of the year, about 3,500–5,000 individuals at the end of the breeding season (Meyer 1995). Florida probably harbors about two-thirds of the remaining swallow-tailed kites, with sub-populations numbering no more than about 100–150 pairs in each of the other 6 southeastern states (Meyer 1995). The Florida Fish and Wildlife Conservation Commission (FWC), in setting priorities for conservation efforts in the state, ranked the swallow-tailed kite as one of Florida’s most vulnerable and poorly understood species (Millsap et al. 1989). Partners in Flight considers the swallow-tailed kite an at-risk species of high priority for conservation action across the southeastern U.S. (Hunter et al. 2001). Swallow-tailed kites have been recommended for consideration for Endangered listing at state and federal levels (Meyer and Collopy 1996). Prior Study Previous research by the project director on the swallow-tailed kite’s breeding biology in Florida, funded by the FWC, examined distribution, nesting success, productivity, habitat selection, foraging range sizes, and communal roosting behavior (Meyer and Collopy 1995; Meyer 1998, unpublished data). Low reproductive potential results from delayed breeding, low success and productivity, and the inability to renest following failure. Strong fidelity to nest and roost sites promotes social behavior and efficient foraging, thus enhancing productivity and survival. Site fidelity, however, concentrates nesting activity and discourages colonization of other sites, increasing the species’ sensitivity to disturbance. Cypress and hardwood swamp forests were selected, and agricultural areas and grasslands were avoided by nesting swallow-tailed kites. The leading cause of nest failure, however, was wind; and nests in pines were significantly more likely to succeed than nests in cypress. Thus, essential

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

nesting habitat for swallow-tailed kites consists of mature, uneven-aged stands of pine and cypress within diverse mosaics of freshwater wetlands, which support the diverse array of small arboreal vertebrates preyed upon by nesting swallow-tailed kites. Large, pre-migration roosts have potential for population monitoring (Meyer 1998). The largest of these roosts, near the western shore of Lake Okeechobee, has formed in the same area each year since its discovery in 1987 (Millsap 1987, Millsap and Runde 1988, Meyer 1998). At its peak in 1992 and 1993, this roost contained 2,200 swallow-tailed kites, or nearly half the estimated U.S. population (Millsap 1987, Robertson 1988, Meyer 1998). Methods were developed for monitoring the development of large roosts, estimating numbers, searching likely habitat for additional large roosts, and estimating annual productivity of the population by observing the relative numbers of adults and juveniles (Meyer 1998). Radio-tracking data indicated that substantial annual variations in the timing of post-breeding dispersal might be related to surface water levels, perhaps due to the influence of water levels on prey populations. Large, pre-migration roosts require forested wetlands in proximity to expansive freshwater marshes, where kites, feeding mainly on flying insects, prepare for migration. The loss and degradation of critical habitat in southcentral and southwestern Florida, where most of the remaining kites nest and roost on privately owned land, jeopardize the U.S. population of swallowtailed kites. The species has been recommended for listing as Endangered at state and federal levels (Meyer and Collopy 1996). Priorities for Further Study Three areas have been assigned the highest priority for further research: demography, post-breeding dispersal, and migration (Meyer 1995). Demographic modeling will help explain the populationâ&#x20AC;&#x2122;s response to historic declines, identify current trends, and focus management efforts on improving the long-term viability of the population. Post-breeding dispersal, which involves broad areas of privately owned lands, includes the development of large communal roosts. Understanding dispersal and roosting behavior, critical elements in the preparation for migration, is essential to developing management and conservation plans for swallow-tailed kites. Long-term protection of swallow-tailed kites also requires identification of migration routes, destinations, and winter habitat requirements. All aspects of their seasonal movements, other than the assumption of a wintering range broadly

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

defined as the northern two-thirds of South America (Robertson 1988), are unknown. As a result, it has been impossible to assess the speciesâ&#x20AC;&#x2122; conservation needs for the half of the year when it is absent from Florida. Scope of the Present Study This report describes a 3-year study of demography, dispersal, and migration of swallow-tailed kites. The proposed project consisted of 3 breeding seasons of fieldwork in southern Florida locating nests and radio tagging young kites in 1995 and 1996, satellite tracking and examining the South American winter range of kites tagged in 1996, and finding and monitoring returning radio-tagged kites in 1997. In March 1997, a contract amendment expanded the project to include locating nests and radio tagging young kites in 1997 in northern Florida, where we had not previously worked.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

OBJECTIVES Original Contract (Southern Florida) 1. Find sufficient nests to radio tag a total of 65 nestlings in 1995 and 1996. 2. During 3 breeding seasons (1995–1997), locate and monitor all surviving birds previously radio tagged (transmitters operate for 2 years). 3. Track all radio-tagged birds during dispersal and pre-migration roosting periods. Determine roost locations, distances from nests, length of attendance in roosts, and foraging range. Estimate annual productivity from roost observations following the protocol developed in a previous study. 4. Use the demographic data and results of previous studies to assess the current status, trends, and long-term viability of Florida’s population of swallow-tailed kites. 5. Provide management recommendations for required habitat, critical areas, and potential threats during the dispersal and pre migration stages. 6. Fit 5 breeding adults with satellite transmitters in 1996 and determine timing, routes, and destinations for southbound migration. 7. Use tracking data to identify concentration points and potential threats enroute and on the winter range. 8. In 1996, visit and describe the general types of South American habitats occupied by adults tracked by satellite. Search these areas for juveniles tagged with VHF transmitters in Florida. Search for pre-migration staging areas and determine departure times for northward migration.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Contract Amendment (Northern Florida) 9. In 1997 locate and monitor 40 nests from Lake Okeechobee northward and westward to the Apalachicola River. 10. Fit 20 nestlings with VHF transmitters. 11. Monitor the post-fledging survival and movements of the radiotagged juveniles.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

METHODS Finding Nests and Radio Tagging Nestling Kites (Objectives 1, 9, and 10) Nest-finding techniques were described in Meyer and Collopy (1995). We searched most intensively during March and early April, when the kites were behaving territorially, courting, and building nests. Once they laid eggs, active territories were less conspicuous and nests were much more difficult to find. Searching for nests was hindered in 1996 by the unusually large number of pairs that failed to produce eggs after occupying previously used territories. Seven years of nest finding in southern Florida gave us a large number of known territories to search in 1995 and 1996. We had no such advantage in 1997, however, when we began studying kites in northern Florida. In addition, most of the kite nests in northern Florida were on private land or public land managed for timber production. We solicited sighting reports beginning in March and referred to files of reports collected since 1988 in the course of working elsewhere in the state. Response to our requests for sighting reports was excellent, but gaining access was time consuming and, in several cases, active sites reported in previous years had been cut before 1997. In all 3 years, juvenile swallow-tailed kites were captured in the nest by a climber using techniques modified from those described in Meyer and Collopy (1995). A light (≤70-kg) climber working in little or no wind could gain access to most nests using this technique, which avoids damage from spurs and is logistically easier than tree-climbing ladders. The best age for radio tagging was around 31 days for normally developed young, or about 7–10 days before fledging. At this age, they were large enough to be properly fitted with the transmitter but too young to jump from the nest. Relatively synchronous nesting within the study population concentrated this trapping window in a 2-week period in late May and early June. Radio transmitters were attached with a backpack harness, but the material and methods differed from those described in Meyer and Collopy (1995). Harnesses were made of 6-mm-wide teflon ribbon (Bali Ribbon, Bali, Pennsylvania). The ends of 4 separate strands were stitched together with cotton thread at a single point prior to the capture and a 12-mm-square of soft material was threaded onto the teflon to form a cushion at the junction, which was placed on the bird’s sternum. In the field, the free ends of the harness were brought up onto the bird’s back (2 anterior to the wings, 2 posterior to the wings and anterior to the legs) and each pair (front and back) was tied in

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

place, then trimmed and glued. Teflon, which is strong, nonabrasive, and nonphotosensitive, has been widely used for transmitter harnesses with excellent results. The cotton thread at the single closure eventually rots away, opening both front and back loops simultaneously and allowing the package to safely fall free. The attachment process was quickly performed in the field, allowing for adjustment with no loss of materials. The single disadvantage was that the teflon does not stretch to accommodate growth or movement. We fitted the harness a bit loosely, but not so loose that the bird could get its head, a wing, or a leg lodged under one of the loops. Locating, Monitoring, and Collecting Demographic Data on Radiotagged Juveniles (Objectives 2 and 11) We monitored all radio-tagged juveniles from a few days prior to fledging until migration. Whenever possible, we checked on the kites from the ground, usually at 4- to 6-day intervals and working outward from the nest area. If a signal could not be detected from the ground for 5–10 days, we tried to locate the bird from the air. As the season progressed, aerial searches for radio-tagged kites were combined with roost-monitoring flights. All flight routes were carefully chosen to cover the greatest area where missing kites were most likely to be found. Radio-tracking range from the air was usually very good. On several occasions, we detected radio signals of flying kites at 90–100 km while circling in a shallow bank at 500–700 m above ground level (AGL). In one case, a radio-tagged kite was detected at a distance of 78 km while the bird was roosting and the aircraft was in straight and level flight at 170 m AGL (the position of the bird was determined by flying directly to the site). Such exceptional range, however, could not be consistently expected. We often were unable to detect signals when conditions were good (high altitude, circling, with the kite presumably in the air at midday) and a bird was known to be within range based on observations shortly before or after the flight. Failure to detect the signal might have been due to the position of the kite during the brief period when the circling aircraft’s antennas and that of the kite’s transmitter were suitably aligned for detection (e.g., the bird may have perched briefly or been low in the air). Several aerial searches were attempted for a particular bird before we assumed that it had left the study area. These searches included low circling flight over the last known location in an attempt to detect a bird that had died and was on the ground (vegetation and water greatly reduce detection range).

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Tracking Dispersing Kites; Locating, Monitoring, and Estimating Productivity at Communal Roosts (Objectives 3 and 11) Dispersing, radio-tagged juveniles (i.e., independent birds that had begun using activity ranges and roost sites away from their natal areas) were tracked from the ground and air. When searching from the air, we flew transects 100 km apart at an altitude of 500–700 m above ground level and an airspeed of about 180 km/hour (previous experience determined that these altitudes and this flight speed were optimal for signal detection and efficiency). Detection ranges were consistently >50 km. The tracking equipment for these flights consisted of a programmable scanning VHF receiver (R-4000, Advanced Telemetry Systems, Isanti, Minnesota) with a 164.000–165.999 MHZ range, wing-mounted 3-element (1995 and 1996) and 4-element (1997) yagi antennas (Advanced Telemetry Systems) connected to the receiver with coaxial cables, a switch-box for selecting either or both antennas, headphones, and an intercom system to permit simultaneous monitoring of the receiver and communication with the pilot. A GPS receiver was used to maintain flight along the specified transects and to determine the coordinates of a kite’s position. Prior to migration, most of the radio-tagged juveniles periodically made long excursions that took them well beyond range of even our aerial searches. Tracking the radio-tagged kites from the ground prior to dispersal led to the detection of neighborhood roosts that were not readily located by following unmarked birds. Aerial tracking of dispersing radio-tagged juveniles resulted in discovery of several large pre-migration roosts that were previously unreported. The largest of the known pre-migration communal roosts, near Lake Okeechobee in Glades County, was systematically monitored from the air and ground. The total number of kites in the Lake Okeechobee roost was estimated from direct visual counts and from photographs taken during morning flights from July to September in 1996 and 1997. Because the roost was linear, occupying a narrow stand of trees 2–3 km long, the flight path that was least disturbing to the birds was an elongated oval surrounding the stand and laterally displaced from the birds by about 250 m. Altitudes varied from 100 to 200 m AGL and airspeed averaged 140–170 km/hour. These conditions allowed for safe operation, little apparent disturbance, and adequate data collection as long as the pattern could be repeated as required, usually for a total time overhead of 15–20 minutes. The birds did not take flight as long as the aircraft remained at least 100–150 m away and 100 m high. If the aircraft passed over the birds, even above 300 or 400 m, large numbers flew up and either drifted off or returned to perches after several minutes, probably depending on thermal or wind conditions.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

The kites’ behavior was more stable and predictable in the morning. Swallow-tailed kites arriving at the roost in the evening may not remain perched for the night until well after dark, often taking flight and realighting in smaller groups. The birds were much more easily disturbed in the evening than in the morning, when it was possible to walk quietly within 50 m of the roost trees without causing any of the birds to fly. Direct visual estimates from the air were made with the commonly used method of counting a portion of the total number (e.g., 50 or 100) and estimating the number of times that unit was repeated. At first, counts varied substantially among observers on the same flight. With practice, however, counts of all observers usually were within a 10% range of each other and of the counts made from aerial photographs. Generally, direct visual counts were lower than those made from photographs. The best aerial photographs for counting roosting kites were taken with a 35 mm camera with automatic film advance and a zoom lens set at a focal length of about 70–100 mm. Focus and exposure were best set manually. Color film was essential for distinguishing the kites’ white heads from the vegetation; speeds of 100 (e.g., Ektachrome 100) to 200 (e.g., Kodachrome 200) offered the best compromise of short exposure and low grain. Highquality ASA 200 film in conjunction with shutter speeds of 1/250 of a second or faster reduced the effects of engine and wind vibration and produced the best results. The most accurate counts were possible when the successive slides shot during a given pass overlapped enough to make omissions or duplications of individual birds apparent. Three or more sets of slides, each including the entire roost, were the best assurance that a flight would produce an accurate count for that morning. Total numbers were estimated from the 35 mm slides by projecting them on a white surface that could be marked with an erasable pen. Portions of the total scene that could be conveniently counted at one time were enclosed with the marker and tallied. Care was necessary to avoid mistaking the white scapulars, which can appear as 2 large blotches on the bird’s back, for 2 heads. This was particularly challenging on slides blurred by camera movement or poor focusing. The same equipment and film were used to photograph rising flocks of kites from the ground during morning departures from the roost. Even though vibration was much less of a problem than during aerial photography, high speed, low grain film (e.g., Kodachrome 200) still produced the best results and made it possible to score a greater number of birds per slide than slower,

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

lower quality film. Automatic film advance with manual focus and exposure also were the best settings for the ground photographs, and plumage details were more apparent in distant birds if the film was underexposed by 0.5–1.0 f-stop relative to the reading of the camera’s internal light meter. In slides taken from the ground juveniles were distinguished from adults by their shorter tails and slightly narrower, shorter wings. Some young birds still appeared to have the pointy wings characteristic of recent fledglings, a condition that gradually disappeared in most juveniles as the 2 longest primaries grew to be more equal in length. Adults in particular stages of molt also appeared to have short tails, but these birds were simultaneously undergoing wing molt that was readily apparent (Meyer and Collopy 1995, Meyer 1998). The relative numbers of adults and juveniles were counted using methods similar to those described for the aerial photographs of total numbers. Usually, 40–60% of the birds in a slide could be accurately assigned to an age class. Because many individuals appeared in more than 1 slide, they undoubtedly were counted more than once. The birds, however, were constantly changing position in relation to each other, thereby continually altering the composition of the slides from one shot to the next. Thus, each slide was treated as an independent sample without any inherent biases regarding relative numbers of adults and juveniles. The ratio of adults to juveniles for each morning that departing kites were photographed was derived from the sums of all adults and all juveniles counted in that day’s slides. Some biases could have resulted from the apparent tendency of juveniles to group together in the roost, particularly on mornings late in the season when relatively few birds were present and when photographs were taken before the departing young became re-sorted among the adults. This situation was relatively obvious, however, and was easily avoided during the photography. Satellite Radio Tagging and Tracking (Objective 6) We fitted 4 adult and 3 juvenile swallow-tailed kites with satellite transmitters from 9 May to 18 June 1996 (Table 1). The satellite transmitters, which weighed about 18 g, were manufactured by Microwave Telemetry (MWT) of Columbia, Maryland, and were attached using the same backpack harness described above for attaching VHF transmitters to juvenile kites. The trap used to capture adults near their nests consisted of 2 2-x-12-m mist nests tied together along their length (making 1 4-x-12-m net) and attached at each end to a pulleyed rope suspended from a tree limb or the top of an extendable

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Table 1. Trapping, banding, and tagging data for 4 adult and 3 juvenile swallow-tailed kites fitted with satellite transmitters during the 1996 breeding season. Transmitter number 16081 16082 16083 16084 16085 16086 05394

Date radio tagged 9 May 10 May 14 May 16 May 31 May 6 June 18 June

Weight (grams)

USFWS band #

475 440 495 455 570 465 405

856-40008 856-40009 856-40010 856-50001 856-70007 1026-56401 1026-56409

Age Adult Adult Adult Adult Juvenile Juvenile Juvenile

pole. A live, disabled barred owl (Strix varia) borrowed from a wildlife rehabilitation facility was tethered to a 2-m perch placed below the center of the net. Two people hid nearby in a portable blind. When a kite dove at the owl and became caught in the net, the net was quickly lowered and the kite safely removed. Setting and running the trap was labor intensive and trapping success varied considerably. Nonetheless, this trap was the safest and most effective method for trapping swallow-tailed kites capable of flight. The transmitter used for this project was the only available model small enough to be used on a bird the size of a swallow-tailed kite. Battery capacity was relatively small, which limited transmitter life and required that the transmitters be programmed to operate intermittently and for a limited number of duty cycles. Our transmitters were programmed to turn on in late July and to transmit for 8 hours every 2 days until mid-September. At that point, the duty cycle slowed to 8 hours every 7 days until early November, then to 8 hours every 30 days. There was a limited trapping period, which was dictated by the age of the juvenile (too young and the disturbance might pose a risk, too old and the adults were no longer aggressive), and the surrounding vegetation did not permit us to trap at all of the nests that survived to trapping age. By the end of May, it was apparent that we were not likely to capture any more adults, so we put the 3 remaining satellite transmitters on juveniles. Although we planned to deploy only 5 transmitters, the cost per unit was less than expected, permitting us to purchase a sixth radio. Transmitter #16082, deployed on 10 May 1996, appeared to be malfunctioning about 3 weeks later and MWT quickly provided a seventh radio as a replacement. The day before the seventh transmitter (#5394) was to be deployed, we learned that #16082 was operating normally. Paul Howey of MWT suggested, however, that we use #5394 as planned, at no charge.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Satellite transmitters, or PTTs (platform transmitter terminals), use an entirely different process to provide location data than conventional VHF transmitters. Location and transmitter-status data are processed and distributed by Service Argos (Largo, Maryland). The PTTs must be on for about 8 hours at a time, during which they emit a brief, encoded message about once a minute. The tracking system uses the Doppler effect and repeated sampling to determine the angle of the PTT in relation to the satelliteâ&#x20AC;&#x2122;s path. Thus, 1 fix requires a large expenditure of stored battery energy, and the size of the battery that can be employed is directly limited by the amount of weight the animal can carry. Fortunately, PTTs can be programmed to vary their duty cycle, thus providing the most data at times when the information is most important and conserving battery power when demands for data are not as critical. The quality (correlated with accuracy) of each location is specified by Service Argos, and the user can decide which locations can be reliably used on a case-by-case basis. This decision is based on acceptable levels of error and the availability of accurate prior and subsequent locations. We obtained useful locations about 60% of the time during the period when the transmitters turned on at 2- and 7-day intervals; few data were obtained after the transmitters shifted to a once-per-30-day duty cycle. For various technical reasons, the system does not provide a location for every 8-hour period that the PTT transmits. This is particularly troublesome when the duty cycle is lengthened (to once a week or longer) to conserve battery power. Accurate locations can be few and far between. The mapped satellite locations do not represent data gathered at consistent time intervals or at any specific time of day. The location data have a range of accuracy from about 300 m to over 10 km. Migration Corridor and Critical Areas (Objectives 6 and 7) The satellite data received from July through December 1996 were evaluated for accuracy to map the routes and determine the destinations of migrating kites. Times and distances between locations were calculated for each radio-tagged kite to produce a profile of the rates of movement and to identify when and where the birds reached the most southerly point of their migration.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Winter Range: Describing, Searching for VHF-tagged Kites, Contacting Cooperators (Objective 8) Two project technicians, John Arnett and Audrey Washburn, spent from 7 November to 8 December 1996 traveling through the area delineated by the destinations of kites tracked by satellite, roughly a 1,400-x-350-km crescentshaped region in southwestern Brazil. Arnett and Washburn made direct observations, took photographs, and gathered maps of areas near the satellitedetermined kite locations where they observed swallow-tailed kites (satelliteÂ transmitters cannot be tracked accurately from the ground with a portable receiver). They visually searched for kites, their roosts, and their nests throughout the region (the trip coincided with the austral summer and, thus, the breeding season of the southern subspecies of swallow-tailed kites). Arnett and Washburn conducted 5 aerial searches, from 11 to 26 November 1996, for juvenile kites radio tagged in Florida with VHF transmitters in 1995 and 1996 and for 9 juveniles radio tagged in southern Louisiana by Jennifer Coulson in 1996.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

RESULTS AND DISCUSSION Nest-finding and Radio Tagging (Objectives 1, 9, and 10) Sample Size – Nests.—We found and monitored 45 nests (in all cases, nest refers to a nest with eggs) in 1995 in Collier, Dade, Hendry, Highlands, Lee, Marion, Monroe, and Polk counties (Table 2), exceeding the number found in any of the preceding 7 years of research (13–31 nests/year, mean = 22.7 ± 2.4 SE). The required search effort, however, was much greater than in previous years (30 hours/nest in 1995 versus a mean of 15 hours ± 1.5 SE for the preceding 5 years) (Table 3). Sighting reports also were well below average in 1995, and local observers subjectively concluded that kites were less numerous in the area. The increased search effort and decreased sightings may have resulted from a lower nesting density in southern Florida in 1995, which, in turn, may have been caused by exceptionally high surface water levels (Meyer 1998). In 1996 we found and monitored 68 nests in southern Florida (same counties as in 1995) (Table 4). Search effort (mean hours required to locate 1 nest) was high in 1996, second only to that for 1995 (Table 3). As in 1995, the overall number of observations of kites in the southern half of Florida was distinctly lower than for 1988–1994. In 1997 we searched for nests only in northern Florida and found a total of 46 from the Green Swamp and Saint Johns Marsh areas north and west to the Apalachicola River (Table 5). This area included Columbia, Dixie, Flagler, Gilchrist, Levy, Liberty, Marion, Putnam, Sumter, Taylor, and Wakulla counties. Required search effort was comparable to that for southern Florida in 1995 and 1996. In 1995 we were unable to return to 1 of the 45 nests with eggs in time to determine its fate (it had been found by helicopter in a remote site late in the season). Of the 44 nests that we could monitor for success and productivity, 24 fledged ≥1 young (maximum brood size was 2) and 20 failed in either the egg or nestling stage (Table 2). Most of the failures appeared to result from damage to the nest and/or the eggs or young falling from the nest, probably as a result of strong winds. The overall success rate (percentage that fledged ≥1 young) was 55%. Thirty-five young fledged from the 44 nests, or 0.80 fledglings per clutch and 1.46 per successful nest. Productivity for the 6-year period ending in 1993 averaged 0.90 ± 0.13 SE (n = 141) young per clutch and 1.43 ± 0.07 SE (n = 141) young per successful nest (Meyer 1998).

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Table 2. Locations, tree type, and fates of 45 swallow-tailed kite nests with eggs located during the1995 breeding season. County

UTM coordinates

Treea

Collier Collier Hendry Collier Collier Collier Collier Collier Collier Collier Dade Dade Dade Collier Highlands Highlands Polk Dade Monroe Collier Dade Collier Collier Dade Collier Collier Dade Collier Polk Polk Collier Collier Dade Collier Monroe Collier Dade Lee Lee Highlands Dade Polk Polk Marion Dade

466795 2899349 473440 2900412 465171 2942270 476060 2899693 495557 2900838 506965 2867855 495220 2901425 504796 2869333 505232 2871354 504894 2871860 541022 2807049 541285 2807002 533689 2808033 474696 2895838 447359 0308557 447428 3038203 468571 3056741 541196 2806939 500607 2850249 447005 2879350 534723 2811103 495994 2866663 473071 2886381 573867 2842005 452991 2897551 448124 2877713 569551 2839405 448391 2871104 484445 3059016 484586 3058806 475862 2899234 473884 2902167 569300 2843341 495132 2900929 498049 2843100 492380 2898973 569471 2839094 428642 2923632 428479 2922482 472704 3052032 569948 2839709 451119 3075521 472489 3073148 430775 3228253 550961 2805999

pine pine pine pine pine pine pine pine pine pine pine pine pine pine pine pine cypress pine pine cypress pine pine cypress casuarina pine pine casuarina cypress pine pine pine pine casuarina pine pine cypress casuarina pine pine pine casuarina pine pine pine casuarina

Fateb

# Radio tagged

F F S S S F F F F F F S S F S F S S S S F F S F S S F F F S F F F S unknown S S S S S F S S S S

1 2

2 2

1 1

1 1 1 1 2

aPine = slash pine (Pinus elliottii), cypress = bald cypress (Taxodium distichum), casuarina = Australian pine (Casuarina equisetifolia). bF = failed, S = successful (i.e., fledged â&#x2030;Ľ1 young).

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Table 3. Hours of search effort per located nest of swallow-tailed kites, by year, 1990–1996.

aMean,

Year

Hours per nesta

1990 1991 1992 1993 1994 1995 1996

13 24 31 24 15 44 68

16 17 10 13 16 30 25

1990–1994 = 15 hours ± 1.5 (SE)

Table 4. Location, tree type, and fate of 68 swallow-tailed kite nests with eggs located during the 1996 breeding season. County

Treea

Fateb

Collier Collier Collier Collier Collier Collier Dade Collier Highlands Hendry Collier Dade Dade Dade Polk Dade Dade Monroe Lee Lee Collier Collier Collier Collier Collier Collier Collier Collier Monroe Monroe Collier Dade Dade Highlands

pine pine pine pine pine pine pine cypress pine pine pine pine pine pine cypress pine pine pine pine pine pine pine cypress cypress pine pine pine pine pine pine pine pine pine pine

S F S F F F F F S F F S F S F F S S F S S F F S F S S S S F S F F S

# Radio tagged 1 1

1 1 1 1 2 2 1 1 1 1 1 2

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Table 4. Continued. County

Treea

Fateb

Highlands Highlands Highlands Collier Monroe Lee Hardee Collier Lee Lee Lee Collier Collier Collier Collier Dade Collier Collier Collier Monroe Highlands Collier Highlands Collier Collier Collier Collier Collier Collier Collier Collier Hardee Dade Dade

pine pine pine pine pine pine pine pine pine pine pine pine cypress pine cypress pine cypress pine pine pine pine pine pine pine pine pine pine pine pine pine pine pine casuarina casuarina

S S F S S F S F S F F F F S F F F S S F S F S S S S S S F S F F unknown unknown

# Radio tagged 1 1 1

2 2 1 1 2 2 1

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Table 5. Location, tree type, and fate of 46 swallow-tailed kite nests with eggs located during the 1997 breeding season. County

Treea

Fateb

Liberty Levy Levy Marion Marion Marion Levy Levy Levy Putnam Sumter Sumter Sumter Marion Levy Marion Marion Marion Marion Marion Marion Marion Levy Levy Columbia Columbia Columbia Wakulla Taylor Taylor Taylor Flagler Flagler Sumter Sumter Levy Wakulla Wakulla Marion Marion Marion Marion Levy Dixie Gilchrist Levy

pine pine pine pine pine pine pine pine pine pine pine pine pine pine oak pine pine pine pine pine pine pine pine pine pine pine pine pine pine pine pine pine pine pine pine pine cypress cypress pine pine pine pine oak pine pine oak

S F F unknown unknown F F S S S F F S unknown S F S S S F S S F unknown S S S S S S S unknown F S F F S S S S S F S S F S

# Radio tagged

2 2 2

1 2 1

1 1 1 2 2 2

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

Nesting success was 43% in 1996 (Table 6). The average for the previous 8 years was 58%. Productivity (young fledged per nest with eggs) was 0.68 in 1996, compared with an average of 0.85 for the previous 8 years (the second-lowest estimate in 9 years) (Table 6). In 1996, when we monitored the greatest number of nests, the study area could be divided into 5 regions that contained 62 of the 68 nests (Table 7). The Bar-D ranch in Highlands County produced the highest estimates and Long Pine Key in Everglades National Park the lowest. Nesting success in the Everglades has been low since Hurricane Andrew, perhaps due to the loss of epiphytes, which are used for nest-building. Nests built since Hurricane Andrew lack the usual amount of epiphytes and frequently fall apart. We observed 3 cases this year of kites pirating epiphytes from nests in Long Pine Key (1 old nest and 2 others under construction), the first time this has been seen. In Big Cypress, success was high but very few nests fledged 2 young, Table 6. Annual success and productivity (young fledged per nest) for 268 swallow-tailed kite nesting attempts (nests with eggs) from 1988 to 1996. Success data are corrected for length of observation period (Mayfield estimates). Year

Number of nests

1988 1989 1990 1991 1992 1993 1994 1995 1996

Percent successful

Young/attempt

41 80 42 77 56 54 61 55 43

0.48 1.27 0.73 1.26 0.87 0.70 0.71 0.80 0.68

23 26 15 23 31 24 14 44 68

Young/successful attempt 1.20 1.57 1.62 1.55 1.42 1.23 1.10 1.46 1.35

Average success, 1988–1995 = 58% Average young/attempt, 1988–1995 = 0.85 Average young/successful attempt, 1988–1995 = 1.39

Table 7. Regional success and productivity of nesting swallow-tailed kites in 1996 (success estimate is not corrected for length of observation period).

Region Bar-D Ranch Big Cypress CREW Blocks Everglades

Number of nests

Percent successful

Young/ attempt

Young/ successful attempt

6 21 16 10 9

83 57 50 40 33

1.50 0.57 0.75 0.50 0.44

1.80 1.00 1.50 1.25 1.33

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

and we observed an unusually high frequency of slow growth and disparate development in 2-bird broods. The Big Cypress region experienced very high winter water levels, followed by very low spring levels. This may have reduced populations of aquatic insects, some of which serve as important prey for swallow-tailed kites. As observed in previous years (Meyer and Collopy 1995), success differed significantly between nests in pine and nests in cypress trees in 1996 (Table 8). Of the 46 nests monitored in 1997 in northern Florida, 65% were successful (i.e., fledged ≥1 young) compared with a mean success rate of 56% for the southern Florida study area from 1988 through 1996. The number of young fledged per attempt was 0.86; 1.32 young fledged per successful attempt. Both productivity figures were nearly identical to the southern Florida means for 1988 through 1996 (0.85/attempt and 1.39/successful attempt) (Table 6). Table 8. Comparison of swallow-tailed kite nesting success (n = 66 nests) in pine and cypress trees in 1996. Tree Pine Cypress

Successful nests 32 1

Failed nests 27 6

Chi-square = 4.34 d.f. = 1 p < 0.05

Sample Sizes – Radio-tagged Juveniles.—Seventeen juvenile kites from 13 broods in southern Florida were captured in their nests in 1995, measured, weighed, and fitted with VHF radio transmitters (Table 9). Eleven of the 24 broods surviving at the appropriate age for radio tagging (a total of 16 young) could not be captured because their nests were in unclimbable trees, bad weather or scheduling constraints prevented timely capture (3 broods), or the kite flew from the nest as the climber approached and could not be recaptured (a single young). Climbing and trapping were hampered by an extended period of bad weather, including a tropical storm. We fitted 35 young of the year with VHF radio transmitters from 16 May to 14 June 1996 (Table 10) at nests in southern Florida. We achieved this proposed goal despite lower than usual nesting density, success, and productivity, by finding a large number of nests and by checking them more frequently than usual to schedule the climbing as accurately as possible. Of

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Table 9. Trapping, banding, and tagging data for 17 juvenile swallow-tailed kites radio-tagged during the 1995 breeding season.

ID#

Nest location (county)

740 111 126 139 158 171 189 219 231 249 262 277 295 308 318 337 354

Collier Polk Lee Collier Collier Highlands Highlands Collier Collier Polk Highlands Dade Dade Monroe Lee Polk Polk

Date radio tagged

Weight (grams)

USFWS band #

Radio frequency

19 May 24 May 25 May 25 May 26 May 29 May 29 May 1 June 1 June 2 June 2 June 3 June 3 June 4 June 5 June 3 July 3 July

440 475 520 440 458 495 443 427 432 505 446 490 480 396 395 403 415

856-30001 856-30002 856-30003 856-30004 856-30005 856-30006 856-30007 856-30008 856-30009 856-30010 856-40001 856-40002 856-40003 856-40004 856-40005 856-40006 856-40007

164.740 165.111 165.127 165.139 165.158 165.171 165.189 165.219 165.231 165.249 165.262 165.277 165.295 165.308 165.318 165.337 165.354

Table 10. Trapping, banding, and tagging data for 35 juvenile swallow-tailed kites radio tagged during the 1996 breeding season.

ID#

Nest location (county)

382 396 414 427 441 459 474 488 503 516 547 557 577 596 623 636 655 667 687 691 706 713 727

Collier Collier Collier Collier Collier Collier Collier Collier Collier Collier Collier Collier Collier Collier Collier Collier Lee Collier Collier Lee Collier Monroe Highlands

Date radio tagged

Weight (grams)

USFWS band #

Radio frequency

16 May 20 May 20 May 22 May 22 May 22 May 22 May 22 May 22 May 23 May 24 May 25 May 28 May 26 May 26 May 28 May 28 May 29 May 29 May 29 May 29 May 30 May 31 May

455 475 445 430 405 465 470 530 470 490 415 470 440 435 415 425 485 410 455 500 445 395 460

856-50002 856-50003 856-50004 856-50005 856-50006 856-50007 856-50008 856-50009 856-50010 856-60001 856-60002 856-60004 856-60009 856-60006 856-60007 856-60008 1026-56407 856-60010 856-70002 856-70003 856-70001 856-70004 856-70005

165.382 165.396 165.414 165.427 165.441 165.459 165.474 165.488 165.503 165.516 165.547 165.557 165.577 165.596 165.623 165.636 165.655 165.667 165.687 165.691 165.706 165.713 165.727

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Table 10. Continued.

ID#

Nest location (county)

733 744 753 760 770 779 790 801 805 807 824 831

Highlands Collier Highlands Highlands Monroe Collier Dade Highlands Highlands Highlands Dade Collier

Date radio tagged

Weight (grams)

USFWS band #

Radio frequency

31 May 02 June 06 June 06 June 07 June 08 June 07 June 08 June 08 June 09 June 11 June 14 June

470 415 495 460 410 400 520 515 430 455 465 435

856-70006 856-70008 856-70009 856-70010 856-60003 856-60005 1026-56403 1026-56404 1026-56405 1026-56406 1026-56402 1026-56408

165.733 165.744 165.753 165.760 165.770 165.779 165.790 165.801 165.805 165.807 165.824 165.831

34 trees with nests in which the young reached tagging age, 30 were successfully climbed (in some cases a second time, if the young were too small when first captured). Two trees were unclimbable, 1 was on private land to which we could not gain access, and 1 nest blew from the tree shortly before we attempted to capture the young (Table 11). This left 38 young available for radio tagging; 3 were fitted with satellite transmitters and 35 with VHF transmitters. In 1997, we achieved our goal of VHF radio-tagging 20 nestlings at nests in northern Florida.

Table 11. Fates of nestling swallow-tailed kites in 1996 with regard to radio-tagging effort. Nesting starts = structures at least partially built. Nesting attempts = completed nests in which eggs were laid. Successful attempts = those in which â&#x2030;Ľ1 young survived to fledging. Total nestlings = young surviving until they could be observed from the ground, at about 1 week of age. Total fledglings = young that reached an age at which they were capable of sustained flight. Nesting starts Nesting attempts Total nestlings Successful attempts Total fledglings Young fitted with VHF transmitters Young fitted with satellite transmitters

46a

aOf the 46 fledglings, 8 were not radio tagged for the following reasons: 2 young (1 nest) fledged early after the nest fell from the tree; for 2 young (1 nest) we could not receive permission for access to private property; and for 4 young (2 nests) the trees were not climbable.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

Sexes of Radio-tagged Juveniles.—Blood samples were collected from the 52 nestlings radio tagged with VHF transmitters in 1995 and 1996 and sex was determined by genetic analysis (polymerase chain reaction [PCR]). Of the 52 nestlings, 24 (46%) were males and 28 (54%) were females, which does not differ significantly from a 1:1 sex ratio. Range Areas (Objective 3) Maps of the post-fledging movements of juveniles in 1996 are presented in Appendix A, and 1997 movements are shown in Appendix B. Post-fledging Period.—In 1995 we monitored the large roost near Lake Okeechobee for radio-tagged kites during 20 survey flights and 14 ground visits. Aerial searches for radio-tagged kites were also conducted during the 20 120-km flights between Oasis Ranger Station, Big Cypress National Preserve, and the roost. We extended 13 of the 20 flights and made 2 additional flights solely to search for radio-tagged kites (22 flights totaling 57.7 hours from 17 June to 13 September 1995). The mean number of days for which we had contact with a radio-tagged kite in southern Florida in 1995 (from the day of tagging until the last observation) was 69.1 ± 25.0 SE (n = 14 surviving birds, range = 50–106 days). In central Florida, however, we lost contact simultaneously with all 6 surviving radio-tagged kites (#s 111, 171, 189, 249, 262, and 337) in early August. The high water resulting from Hurricane Erin, which passed through central Florida early on 2 August, may have caused displacement of these 6 birds, all of which disappeared between 3 and 10 August. Two of the missing central Florida kites were subsequently relocated: #337, on 23 August at the large Lake Okeechobee roost, 80 km south of its last known location; and #262, on 12 September 17 km northwest of LaBelle, Hendry County, or 81 km southwest of its last known location. The other 4 central Florida kites could not be found by 14 September 1995. One juvenile (#308) was first found near the Lake Okeechobee roost on 18 July 1995, a distance of 134 km from its nest, but it continued to roost 2–23 km from the main roost until 7 August. It was present in the main roost during 7 subsequent observations, until 31 August. On 1 September, #308 roosted 65 km to the northeast, but was back in the main roost during the season’s last 3 observations, from 6 September to 14 September. The second juvenile (#139) consistently roosted with ≤11 other kites in a small area near its nest until 7 August. On 11 August, it was in the large roost near Lake Okeechobee (102 km from its nest), which it consistently used until 31 August. During the first half of September, it was in the large roost during half our observations and

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

roosted 20â&#x20AC;&#x201C;33 km away the rest of the time. The third juvenile (#126) roosted near its nest until 20 July, was in the large roost on 25 and 27 July (89 km from its nest), but roosted back near its nest on 29 July. On 11 August, #126 roosted 8 km south of the large roost and was in the large roost when it was last located on 14 August 1995. The fourth juvenile (#337) roosted near its nest or 36 km to the south, near the Kissimmee River, until 10 August. We were unable to locate #337 until 28 August, when it was found at the large roost, 90 km from its nest. It was there during 2 of the next 3 radio checks but was 78 km southeast on 8 September 1995 and 54 km southwest on 14 September 1995. Three (#s 308, 139, and 337) of the 47 kites present in the large roost on 6 September 1995 were radio-tagged birds. The same 3 kites were present on 14 September, when a total of 23 birds were roosting, but only #308 was in the roost during our flight on 8 September (#139 was 20 km from the roost, and #337 was 78 km from the roost). In addition to the 3 birds observed in the large roost on 14 September 1995, we also had contact with a fourth kite (#262). This kite, which had been missing since last detected on 10 August within 10 km of its nest, was found in the air about 17 km northwest of LaBelle, Hendry County, or about 92 km south-southeast of its nest. Locating dispersing radio-tagged kites required greater effort than anticipated and observations of foraging ranges, habitat, and prey selection during the pre-migration period were limited. Most of this information came from the 4 radio-tagged kites that used the large roost near Lake Okeechobee. As in 1992 (Meyer 1998), foraging ranges for these birds were to the northeast and southeast of the roost, over the freshwater marshes and remnant wetlands bordering the western shore of Lake Okeechobee. Foraging kites usually remained fairly high (>100 m) and preyed on flying insects, although they also hunted over hedgerows, isolated stands of trees, patches of shrubby vegetation, and emergent vegetation of ponds and marshes, perhaps in pursuit of frogs, snakes, and anoles. In only 1 case was a radio-tagged kite located west of the Lake Okeechobee roost following morning departure. As noted previously, foraging ranges were relatively linear, extending about 20 km to the northeast and southeast from the roost. The 35 juveniles radio tagged during 1996 were tracked from the ground and air. We usually located each bird at least once every 5 days. For several birds, there were periods of 1â&#x20AC;&#x201C;3 weeks when we were unable to receive a signal, only to locate the bird in a previously occupied area. As of the end of June, when most young of the year were making the transition to independence from their parents, 8 (#s 427, 441, 459, 636, 691, 713, 727, and 733) of the 28 surviving radio-tagged juveniles were within 10 km of their nests, 3 (#s 557, 623, and 744) were within 2 km, and the remaining 17 were

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

within 500 m. The timing and extent of these movements were consistent with previous years’ observations. In late June and early July 1996, each of the young kites gradually began increasing the size of its activity range. From mid-August, when some of the young apparently began migrating southward (based on southward movements followed by sudden absences and on data from young with satellite transmitters), to 19 September, when the last radio-tagged juvenile began its migration, individual tagged kites were found covering increasingly larger areas. In most cases where we were able to document movements well, the juveniles ranged over most of the central and southern portions of the state. Figures 1 and 2 illustrate the movements, including apparent departures on migration, of 2 radio-tagged juveniles for which we were able to gather data until they left Florida. The scale of these birds’ movements is typical of that of the other 21 radio-tagged juveniles for which we have extensive tracking data on dispersal. The radio locations and intervening straight-line distances for #831 from 17 to 20 September (Fig. 1) and for #805 from 2 to 13 September (Fig. 2) totaled well over 170 km on some days (the actual route undoubtedly was longer). Lengthy moves to the south, suggesting the onset of migration, were often followed by reverse, northward movements of equal magnitude. The young kites may have been awaiting weather conditions favorable for migration; the reasons for their long daily excursions, however, are not clear. The longest movement from the natal area for any radio-tagged juvenile (satellite or VHF transmitter) was that of #16085, carrying a satellite transmitter (Fig. 3). This kite, tagged in Highlands County, ranged over large portions of northern Florida, from Duval County to the Apalachicola River in Liberty County and into southeastern Georgia (Camden County) from at least 15 August 1996, when it was first detected, until 3 September, after which it moved to northern Hillsborough County (5 September) and southern Mexico (19 September). On 6 September 1996, #733, the sibling of #16085, was detected from the air in eastern Sumter or western Lake County, the second most northerly excursion of any radio-tagged kite (second only to that of #16085). This was the northernmost radio-tracking flight of the year; it originated in Archer (Alachua County) and covered parts of Alachua, Gilchrist, Lafayette, Dixie, Levy, and Marion counties. The only kite detected was #733. The discovery of #733 coincided with the southward movement of its sibling from Levy to Hillsborough County. The 6 September location for #733 and the 5 September

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. 1. VHF radio locations of swallow-tailed kite juvenile #831 from 17 to 20 September 1996. Circles indicate day locations, stars are night roosts.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. 2. VHF radio locations of swallow-tailed kite juvenile #805 from 2 to 13 September 1996. Circles indicate day locations, stars are night roosts.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. 3. Satellite-derived locations of swallow-tailed kite juvenile #16085 from 15 August to 5 September 1996. Circles indicate day locations, the star represents the nest location, and dashed lines show sequential movement (not necessarily the birdâ&#x20AC;&#x2122;s exact route between points). The northern locations were on or near the St. Johns, Santa Fe, and Apalachicola rivers.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

location for #16085 were <70 km apart. It is interesting that the 2 kites with the greatest northern excursions of any radio-tagged kites (VHF or satellite transmitters) were siblings; perhaps the 2 were traveling together. The post-fledging movements of another juvenile carrying a satellite transmitter (#16086) began on 7 August 1996, progressed through its attendance in the Lake Okeechobee roost, and ended with its departure on migration on 29 or 30 August 1996 (Fig. 4). The 20 juveniles tagged as nestlings during the 1997 nesting season were tracked from the ground and air on the same schedule used in 1995 and 1996, with similar results. At the end of July, we were still in contact with all of the 1997 VHF-tagged juveniles, and most remained within 50 km of their nests. By early August, however, we began detecting large movements by some birds. Six of the surviving 16 tagged juveniles remained relatively close to their natal areas throughout August and much of September. Five of the 16 moved distances of 120â&#x20AC;&#x201C;160 km from their natal areas, in every case in a westerly or southwesterly direction, and then settled into a rather well-defined area for at least several weeks. The remaining 5 kites moved away from their natal areas at some point during August but did not appear to settle into defined areas. Two of these were lost almost immediately and never relocated; the other 3 reappeared periodically at least 120 km from their natal areas (2 were found well north of their nests and moving southward after long absences). In mid- to late August, we were able to track 4 of the kites on long, sudden moves from areas they had occupied for at least several weeks. We lost contact with 2 of these kites in south-central Florida following long southeasterly moves (mid-August). A third was tracked in 1 day from southeastern Levy County, where it had been for 2 months, to a location in DeSoto County after dark. We never found this bird again and assume it either moved through the night or departed very early the next morning on a rapid offshore flight. A cold front was passing and winds were strong and northerly. The fourth bird (#805) (Fig. 5) was observed leaving Levy County southbound at 1900 hr on 23 August, also on northerly winds following an unusually strong cold front for this date, and was next located the following afternoon in Lee County. It spent the night in the Corkscrew roost, arriving at 1915 hr, a straight-line distance of 340 km in just over 24 hours. The next morning, it quickly flew south until reaching the mangrove forest fringing the southwestern coast. Its progress slowed at this point, and it turned southeastward, staying near the coast until late afternoon when the signal was lost somewhere between Everglades City and Whitewater Bay, perhaps because the bird moved offshore.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. 4. Satellite-derived locations of swallow-tailed kite juvenile #16086 from 7 August to 5 September 1996. Circles indicate day locations, the star represents the nest location, and dashed lines show sequential movement (not necessarily the birdâ&#x20AC;&#x2122;s exact route between points). The northeastern-most location is at the large communal roost near Lake Okeechobee.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

Fig. 5. A 24-hour movement tracked by VHF telemetry for swallow-tailed kite juvenile #805 on 23 and 24

August 1997. The star represents the bird’s nest site and the dot indicates Corkscrew Swamp Sanctuary,

where the kite roosted on the night of 24 August before flying offshore on 25 August.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Kites ≥1 Year Old.—No kites ≥1 year old (i.e., birds tagged in previous years) were detected in 1995. In 1996 we relocated as yearlings 3 of the 14 juveniles radio tagged in 1995. All 3 were from central Florida nests and were found near, or at least at the same latitude as, their natal territory. In 1997 we relocated 5 kites radio tagged as nestlings in southern Florida in 1995 (1) and 1996 (4). The 1995 bird and 2 of the 1996 birds were first detected during aerial searches in northern Florida on 4 June 1997. We maintained intermittent contact with the 2 1996 kites during ground and aerial searches in northern Florida until late June and early July 1997, prior to which they gradually moved southward. After this time, they were briefly monitored in central Florida but were never detected in southern Florida. The other 2 kites radio tagged in 1996 were first detected in southern Florida during aerial searches in May and were intermittently relocated through June. Movement Patterns.—The 8 radio-tagged kites relocated at ≥1 year old displayed 2 general patterns. The 3 kites from 1995 nests in the south-central part of the state were first detected within 100 km of their natal areas in 1996. The same was true for 2 of the 5 kites (both 1-year-olds) relocated in 1997. The other 3 kites relocated in 1996 (2 1-year-olds and 1 2-year-old) were in northern Florida, over 400 km from their natal areas in southern Florida. These 3 gradually moved southward over the summer but were never detected near their natal areas prior to their presumed departure on migration in August. Even the 5 kites relocated at some point within 100 km of their natal areas eventually ranged widely, in some cases joining large pre-migration roosts. Prior to 1997 we did not conduct aerial searches in northern Florida. It is possible that some of the kites that were never detected as 1-year-olds in 1995 and 1996 were in this part of the state or elsewhere to the north and west. Roosts (Objective 3 and 11) Locations and Sizes – 1995.—As a result of radio tracking, 13 small roosts numbering 3–12 kites, including 1 or 2 radio-tagged juveniles, were detected in or near nesting neighborhoods. The sizes and exact locations of some of these roosts varied from one observation to the next, as was noted previously (Meyer 1998). The roost sites consisted of mixed swamp forest, riparian hammock, hydric pine fringes of swamp forest, or insular mesic oak hammocks within wetland/upland mosaics.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

Three larger roosts first observed in 1988 and 1989 and apparently central to large concentrations of nests (i.e., perhaps several neighborhoods of 2–5 nests each) were active during the 1995 breeding season (Fig. 6). They were located in Everglades National Park (Taylor Slough, southeast of Hole-in-theDoughnut), the Bear Island Unit in northwestern Big Cypress National Preserve (near the north boundary and Okaloacoochee Slough), and Corkscrew Swamp Sanctuary. The Taylor Slough site, near where 40 kites were found roosting during the 1989 breeding season, had 39 roosting kites on the morning of 3 August 1995, including 2 radio-tagged juveniles (#s 277 and 295) from nests within 10 km. The area consisted of cypress heads in freshwater marsh. The Bear Island roost had 37 kites on the morning of 26 July, including 1 radio-tagged juvenile (#158) from a Bear Island nest. The site was mixed swamp forest (cypress and deciduous) with small, embedded ponds. A roost of 30–35 kites was found near this site in 1989 (Meyer and Collopy 1995). On the morning of 29 July the Corkscrew Swamp site had 90–100 roosting kites in exactly the same location that had been used annually since the roost was discovered in 1988 (Meyer and Collopy 1995). The site consisted of mixed swamp forest. As in the past, the kites mainly used large cypress snags clustered around a few small ponds near the edge of a large freshwater marsh. Counts for these 3 roosts probably represent the approximate high for the season, since all 3 observations were made within 1 week of the peak at the large roost near Lake Okeechobee. We flew over the roost to photograph and count perched kites on 19 mornings from 17 June to 14 September 1995 (Fig. 7). Visual counts during the flights increased from about 50 kites on 17 June to a high of 1,650–1,700 on 26 July, then decreased to 23 kites on 14 September. Concurrent photographic counts during 6 flights were usually within 10% of the visual counts but, unlike in 1992, sometimes less than the visual counts. In general, the 1995 night roosts of the 6 surviving central Florida radiotagged kites contained fewer birds and varied more in location over time than the roosts of the 8 surviving south Florida radio-tagged kites. Locations and Sizes – 1996.—Previously observed roosts at Lake Okeechobee, Corkscrew Swamp Sanctuary, and Everglades National Park were again active in 1996. Lake Okeechobee had 1,350 kites at its peak in late July; Corkscrew had 110, and Everglades had 30 at the same time. Corkscrew Swamp Sanctuary staff counted 187 at that site 1 week earlier, suggesting that this roost may have peaked earlier than usual this year. Lake Okeechobee also peaked earlier than usual. The total number at Lake Okeechobee was lower than that counted in any year since systematic counts were begun in 1987.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. 6. Study area in southern Florida. Dashed ellipses indicate general locations of nests and associated small communal roosts (BC = Big Cypress Swamp, E = Everglades). Stars indicate locations of large communal roosts (FC = Lake Okeechobee [near Fisheating Creek], C = Corkscrew Swamp, CR = CREW).

Fig. 7. Aerial counts (visual and photographic) of roosting swallow-tailed kites at Lake Okeechobee, 17 Juneâ&#x20AC;&#x201C;14 September 1995.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

Six additional pre-migration roosts were found. The largest, on public land (Southwest Florida Regional Airport) adjacent to the area being acquired under the CREW (Corkscrew Regional Ecosystem Watershed) initiative, contained about 180 kites when found in late July. It was occupied by some of our radio-tagged kites from nests on CREW lands. This site was consistently occupied by decreasing numbers of kites for the remainder of the season. Three roosts east of the Devil’s Garden area in Hendry County were first observed in late July. Two were consistently used through August, while attendance at the other was more variable. The combined total at the 3 Devil’s Garden roosts was about 75–90 kites (the 2 largest roosts, totaling 60–75, were counted on the same morning). Two roosts totaling ≥36 kites were regularly used in the Southern Blocks of Collier County. These 2 sites began as breeding-season neighborhood roosts and remained active through most of August. In addition to the 9 observed sites, additional roosts, each consisting of <30 kites, were suspected based on radio locations of tagged kites: northeastern Big Cypress National Preserve (northern Addition Land, north of I-75; southern Addition Land, south of I-75); the southeastern portion of the Seminole Indian Reservation (southern Hendry and northern Collier counties); just north of Highlands Hammock State Park (western Highlands and eastern Hardee counties); eastern Highlands County, west of Archbold Biological Station (contained radio-tagged birds from the Bar-D Ranch study area); the southwestern portion of Avon Park Air Force Range or adjacent private land (Highlands County); and the southeastern portion of Avon Park Air Force Range, near the Kissimmee River (Highlands or Okeechobee County). The large Lake Okeechobee roost began to form during the second week of June. We flew over the roost to photograph and count perched kites on 11 mornings from late June to late August 1996. Visual counts during the flights increased from about 200 kites to a high of about 1,350 on 24 July, then decreased to 775 kites on 7 August and 50 on 23 August. Concurrent photographic counts during 4 flights were within 10% of the visual counts. The roost peaked earlier and the number of kites present at the peak was about 20% less than in 1992 (Meyer 1998) and 1995. The peak in 1996 was nearly 40% smaller than that observed during 1993 and 1994, however, when about 2,200 kites were present (Meyer, unpublished data). It is possible that the same factors responsible for the apparent lower density of nesting kites in southern Florida in 1996 (e.g., high winter surface water levels, as in 1995) continued to cause some kites to range more widely or to establish temporary activity ranges (or breeding territories) outside the region. Tree-cutting and some road construction along the levee adjacent to the roost also may have

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

been a factor in the smaller numbers and in the unusually rapid rate at which the roost declined. These activities appeared to alter the typical pattern of morning departures, as well; the kites moved away from the levee more rapidly than usual and gathered into flocks over the adjacent marshes rather than above the levee. Locations and Sizes – 1997.—We located 29 roosts in northern and central Florida ranging in size from 1 to ≥50 kites (mean = 17.6; s.d. = 15.1) by tracking radio-tagged young of the year. These sites were distributed among the following counties: Gulf (1), Wakulla (1), Jefferson (1), Columbia (2), Dixie (3), Gilchrist (1), Levy (4), Marion (5), Putnam (5), Sumter (3), Polk (2), and Hillsborough (1). Requests for sighting information from agency, academic, and organization personnel produced 1 particularly helpful report on 2 August 1997 of a roost of at least 250–300 swallow-tailed kites at Lake Woodruff National Wildlife Refuge. A few of our VHF-tagged juveniles moved eastward into this general area in August, perhaps attracted to habitually used roosting and foraging areas. We also learned of an aggregation of 50–60 that used an area on Ft. Stewart, Georgia, near the Ogeechee River for an extended period of time in August. This site is on the route used by the satellite-tagged adult from Osceola National Forest that traveled to the Savannah River (just north of the Ogeechee) and remained there for 5 weeks before rapidly moving southward on migration (see below). Useable fixes for satellite-tagged kites provided at least an additional 10 roost locations in the southeastern U.S. (based on local time from 2200–0700 hr), but because we did not observe these roosts visually, we do not know how many kites were present. Three of these general locations were used a total of 8 times by 2 different kites over periods of several weeks. One of the 10 locations, for an adult tagged in Louisiana, was along the Apalachicola River about 14 km south of Blountstown, in the general area where an aggregation of about 200 kites was reported several years ago (B. Millsap, FWC, personal communication). Roosts of satellite-tagged kites were very close to the following rivers: Savannah, Aucilla, Apalachicola, Alabama (Mobile Delta), Tombigbee, Pascagoula, Pearl, and Mississippi. One kite also roosted in the Lake Okeechobee roost for at least 1 night. The roost fixes, as well as most of the daytime locations, for the satellite-tagged kites were nearly all in areas noted for the presence of swallow-tailed kites. With the possible exception of the Mississippi River site, none of the tagged kites has revealed any previously unknown kite activity areas, indicating that our impression of distribution beyond Florida, though sketchy and based on very little data, is probably fairly accurate.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

The individual roosts that we located were found too late or were too small or inaccessible for us to repeatedly photograph morning departures and estimate age ratios. This must be done near the time when the roost reaches its peak in order to standardize the observations with respect to time of season. Adults depart on migration prior to juveniles, thus rapidly skewing the ratio at an unpredictable rate (see Meyer 1998). Knowledge of these sites, however, will permit such effort in subsequent years. In a relatively short time during the 1997 season, VHF and satellite transmitters have yielded a considerable number of roost sites that might be habitually used by swallow-tailed kites and, thus, important for the purpose of designing a long-term monitoring plan. Considerable work remains to observe as many of these sites as possible to determine the size of each roost and extent of site fidelity. Attendance.—Four of the 14 surviving radio-tagged juvenile kites used the large communal roost near Lake Okeechobee in 1995, but none roosted there continuously, as radio-tagged kites apparently did in 1992. Our observations were less frequent in 1992, however, and we easily could have missed brief absences. Occupancy at the large roost by the 4 radio-tagged juveniles, from their first to last detection of the season (ignoring intervening absences), averaged 24.8 days ± 6.4 SE (range = 9–37). Consistency of use (percentage of radio checks during which a kite was present at the roost, from its first detection of the season to its last) varied from 50 to 92%. In 1996 the radio-tagged juveniles moved among roost sites more than expected based on previous observations of marked kites. Each individual had a single site that it used most of the time, but nearly all the kites used up to 2 other known roosts at various times. Timing, Development, and Estimates of Productivity at Large Roosts.— The large pre-migration roost near Lake Okeechobee began to form during the second week of June 1995 (noted from the air before we began systematic counts). About 50 kites were present 39 days before the peak and 47 were present 42 days after the peak (Fig. 7). We observed the large roost from the ground on 14 mornings evenly spaced over the period 13 July–31 August 1995. Analyses of photographs taken on 9 mornings are presented in Table 12 and Fig. 8. The timing of the roost’s peak and the number of kites present were essentially the same as in 1992 (Meyer 1998). The peak was smaller than that observed during 1993 and 1994, however, when about 2,200 kites were present (Meyer, unpublished data).

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Table 12. Numbers of swallow-tailed kites and relative proportions of adults and juveniles in photographic analyses of roost departures at Lake Okeechobee, 13 Julyâ&#x20AC;&#x201C;31 August 1995.

Date 13 July 20 July 27 July 01 August 02 August 07 August 14 August 22 August 28 August

Number present

Number photographed

Number scored

Adult: juvenile

Percent juvenile

930 1,320 1,550 1,000 920 770 500 270 210

515 604 613 386 710 590 190 270 170

273 281 327 173 377 305 102 124 94

7.3:1 8.1:1 8.6:1 8.6:1 6.7:1 3.8:1 2.3:1 0.2:1 0.2:1

12.0 11.0 10.4 10.4 13.1 20.5 30.4 83.6 83.1

Fig. 8. Relative percentages of adult and juvenile swallow-tailed kites determined from photographs of morning departures at the Lake Okeechobee communal roost, 13 Julyâ&#x20AC;&#x201C;31 August 1995. Counts were made on the dates shown.

The ratio of juveniles to adults increased as the total number of roosting kites declined during August and early September 1995, indicating that adults end their seasonal use of the large roost, and probably begin their southward migration, sooner than young of the year. This is consistent with data from roost observations in 1992 (Meyer 1998). As in 1992, overall rates of change were relatively steady, except for the first week of August, when the number of kites dropped more precipitously than in 1992. This period, roughly the first week after the peak of the roost, also was unusual in that the ratio of juveniles to adults (Fig. 8) did not increase as rapidly as it did following the peak in 1992, when a disproportionately larger number of adults vacated the

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

roost. These 2 observations in 1995—the sharp decline and the apparent proportionality of juveniles and adults among the departing kites—supports the suggestion that the passage of Hurricane Erin on 2 August may have caused an usually large number of kites to vacate the Lake Okeechobee roost in a short period of time. It appears, furthermore, that juveniles and adults responded by leaving the area in equal proportions. The 1995 data for juvenile/adult ratios differ from those of 1992. The change in relative proportions of the age classes was less gradual in 1995 (Fig. 8), perhaps due to the effects of Hurricane Erin early in the declining phase of the roost. The storm may have caused an unusually large number of juveniles to leave early. After mid-August, however, large numbers of adults vacated the roost in a fairly short period, rapidly shifting the ratio in favor of juveniles (Table 12). By the third week of August, over 80% of the roosting kites were juveniles, a greater percentage than was present in September 1992. The 1995 data also differ in that only 13.1% of the kites were juveniles 1 week after the peak, versus 16.8% in 1992. Although this difference appears small, the predicted percentage of juveniles in the roost, when the population’s age classes are equally represented and individual pairs experience average productivity, is 13 to 17%, depending on whether an average of 1 (17%) or 2 (13%) nonbreeding adults occur for every breeding pair (Meyer 1998). Nesting success and productivity were average in 1995 (Table 6), suggesting that the low population productivity indicated by the roost data could have resulted from a higher than normal number of nonbreeding adults during 1995. This interpretation is consistent with the conclusion that fewer pairs in the study population produced eggs in 1995. An alternative explanation for the apparent difference in productivity data between 1992 and 1995 is that the age classes are not equally represented at large roosts at exactly the same time, in relation to the peak, from one year to the next. It may not be possible to infer trends in annual productivity from short-term (e.g., between 2 years) differences in juvenile/adult ratios of roosting kites. We will have to evaluate the method over a longer period in order to judge its accuracy. In 1996 we observed the large roost from the ground on 9 mornings from 28 June to 4 September and photographed departing kites. As in 1995, the juvenile/adult ratios differed from those of 1992 in that only 13.9% were juveniles 1 week after the peak, versus 16.8% in 1992. As in 1995, nesting success and productivity were average in 1996 (Table 6), suggesting that the low population productivity indicated by roost observations could have resulted from a higher than normal number of nonbreeding adults during 1996. This interpretation is consistent with the conclusion that fewer pairs in the study population attempted to nest in 1995 and 1996.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Post-fledging Mortality (Objective 2) In 1995 1 radio-tagged young (#318) was found dead in the nest on 21 June, about 9 days after it should have been capable of leaving the nest (its plumage was fully developed). The cause of death could not be determined. This bird had been captured following 4 days of relatively continuous rain and its weight at the time was 395 g. The mean weight for the 13 kites captured during the preceding 15-day period was 465.7 g ± 8.6 SE. Depressed condition, possibly due to low parental feeding rates during extended periods of bad weather, probably was at least a contributing factor in the death of #318. Two more radio-tagged juveniles died during the 1995 post-fledging period. One (#354) was found dead 50 m from its nest on 25 July; its condition and our radio-tracking data indicated that it was alive at least until 15 July, or about 3–8 days post-fledging. The second dead juvenile (#219) was recovered on 28 July less than 100 m from its nest; it fledged around 8 June and its radio signal indicated it was alive at least until 7 July. Cause of death could not be determined in either case, but the timing and the location of the carcass are consistent with cases during previous years in which recent fledglings were depredated or died of starvation near their nests soon after fledging. One of the dead juveniles (#354) came from the latest-fledging nest of our 1995 study sample (n = 44 nests). This kite and its sibling (#337), which survived, reached fledging age 12–15 days later than expected based on their estimated age when the nest was found. Thus, 3 of the 17 radio-tagged juveniles (18%) were confirmed dead by the end of the field season. Ten (29%) of the 35 juveniles radio tagged with VHF transmitters during 1996 died from late May to early August. One bird (#779) had developed unusually slowly, fledging 14 days after its sibling, and was twice observed on or near the ground soon after fledging. It weighed 270 g when found dead and had weighed 400 g when captured. Three birds in one area (#s 474, 667, and 706) appeared to have been killed by an avian predator. Juvenile #382 died near its nest soon after fledging and few remains were found; #655 was found dead but intact on its nest after fledging, with no evidence as to cause of death; #807 was found dead on a residential rooftop in Highlands County; #441 was found scavenged near the large CREW-area roost; and #577 was found dead with an abdominal wound, grasping a small limb with part of the radio harness around a small projection on the limb. The abdominal wound seemed to have occurred prior to when the bird perched, and the manner in which the harness was caught on the limb was unlikely to have prevented the bird’s flight from the perch (the projection was small and there was no abrasion to suggest a

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

struggle). With the possible exception of #577, the transmitter, antenna, and harness did not appear to be implicated in any of the birds’ deaths. In 1997, 5 (25%) of the 20 radio-tagged young died after fledging and prior to fall migration. Two of the deaths apparently were the result of an avian predator, probably an owl, and occurred soon after fledging when the kites were still roosting at night in their nest. This assumption is based on the presence of fresh feathers (i.e., clean and unscavenged) in and below the nest and the presence of the other remains along with the radio transmitter over 500 m away in a swamp forest. The kites apparently were captured in their nest and carried to the site where the soiled remains and transmitter were found. A nocturnal predator, such as an owl, is most likely because the kites had already fledged and were only using the nest as a night roost. Barred owls are common and nest in the area. Causes of the other 3 deaths, which occurred from 2 to 4 weeks after fledging, could not be determined. The carcasses were found from several hundred meters to about 1.5 km from the juveniles’ nests. Thus, 25% of our 1997 VHF radio-tagged sample of 20 young of the year died in the 3-month period between fledging and fall migration. In the last 6 years of study in which a total of 92 juveniles were radio tagged, 18–26% of the marked birds died per year during the post-fledging, pre-migration period (K. Meyer, unpublished data). Survival (Objective 2) Relocations of Radio-tagged Kites as 1-year-olds.—In 1996 we made over 400 attempts from the ground to relocate the 14 radio-tagged juveniles assumed to be alive at the close of the 1995 breeding season (17 young were radio tagged in 1995). These searches began near the birds’ natal territories but were expanded to include all locations in central and southern Florida where we were searching for and monitoring active nests. We began aerial searches in April and flew 16 times from then until late August, a total of 52.6 hours (about 8 hours were ferry time from the contractor’s base to the study area). Three of the 6 radio-tagged central Florida birds and none of the 8 southern Florida birds from 1995 were relocated during the 1996 breeding season. Of the 52.6 hours, 8.5 were contributed by the National Park Service, the Florida Fish and Wildlife Conservation Commission, and ARCI. Three of the 14 1995 birds were relocated in 1996. Bird #171, fledged from Highlands Hammock State Park, was found in Manatee County on 25 April and near the park on 3 occasions during May, but was never found again. Kite #262, fledged from Avon Park Air Force Range, was found on the range on 25 June,

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

about 9 km from its natal site. Bird #249, fledged from the Kicco Wildlife Management Area, was found on 25 April 15–25 km west of Vero Beach, or about 95 km from its natal site, but by late June it had moved south to the northeast corner of Big Cypress National Preserve, 190 km from its natal site. Detections of these 3 yearling kites were more sporadic and less frequent after June, suggesting wide-ranging movements of these nonbreeding birds. On 2 August, #171 was in the Lake Okeechobee roost, the first time it had been located since May. From 8 July to 2 September, #249 was found in roosts in Big Cypress National Preserve and Devil’s Garden. During July, #262 roosted and foraged near the Kissimmee River, south of Avon Park Air Force Range; it was last detected on 15 August 1996 at the Lake Okeechobee roost. Wide-ranging aerial searches in 1997 over most of the state from Liberty to Monroe counties (173 hours and >11,000 km of transects) detected 5 kites tagged with VHF transmitters in southern Florida in previous years. Of these 5 kites, 4 (all yearlings) were tracked sufficiently to determine that they were not breeding and, for the most part, were spending little or no time near their natal sites. Two of the 5 kites were found in southern Florida, and they remained there until the beginning of August. The other 3 kites from southern Florida nests first appeared in northern Florida in 1997. We maintained contact with 2 of these 3 birds until the first week of August, prior to which they gradually moved southward. None of the 5 kites tagged in previous years was relocated after the first week of August despite surveillance on every subsequent flight in northern, central, and southern Florida and frequent (i.e., 2–4 times per week) radio checks of the known large roosts at Lake Okeechobee, Corkscrew Swamp, and the CREW lands. In 1996, we relocated 3 kites tagged as nestlings in 1995 and tracked them for about 1.5–2.0 months. We lost contact with all 3 between 29 July and 7 August (1 was last detected in the Lake Okeechobee roost on 2 August). The large roosts in southern Florida had peaked during the last week of July in each of at least the last 7 years. The 1996 and 1997 detections and movements of yearling or older kites tagged as nestlings indicated that they were not breeding. Instead, they made continuous, wide-ranging movements, probably covering much of Florida, parts of the Southeast, and even beyond. Some individuals loosely associated with their natal area while others clearly did not, which may have been a function of sex.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

Second Year.—We have found only 1 2-year-old radio-tagged kite. This was a bird tagged in southern Florida in 1995 and detected briefly in early June 1997 in northern Florida (its transmitter appeared to be failing at the expected time). Alternative Explanations.—In previous years, 1-year-old kites (identified by their short tails) usually were not seen until the end of March and early April. In 1996 the first yearling kite was seen on 23 March, near Kissimmee. Yearlings returning to Florida may arrive later than older kites. We counted the numbers of 1-year-old kites observed in flocks from 23 March to 31 May (Table 13). Yearlings accounted for 4.1% of the 507 kites that we were able to age. The range for 4 observers was 3.3–5.2%. The 2 methods for estimating the proportion of young that return after 1 year—relocations of radio-tagged yearlings and counts of yearlings in flocks—yielded similar estimates. Based on annual productivity estimates from 1988 to 1995, the percentage of young in the population after fledging and before post-fledging mortality should be 18–22%, depending on whether there are 1 or 2 nonbreeding adults per breeding pair (Meyer 1998). Counting yearlings indicated that about 20% of the young produced in 1995 returned in the spring of 1996 (a reduction from about 20% of the population prior to fall migration to 4%), while the relocations of radio-tagged kites indicated that 18% (3 of 17 radio-tagged birds) returned. Birds that do not return could be accounted for in several ways: radio failure (or loss due to a failed harness), radio-induced mortality (e.g., due to impaired flight); natural mortality; dispersal beyond radio range (elsewhere within the U.S. or remaining in Latin America following migration); and sampling error. The fact that the 2 estimates, including 1 that is unbiased with regard to the radio transmitters, are so similar suggests that radio-related causes are not a major factor. If dispersal is a major cause, we might expect Table 13. Numbers of yearling and >1-year-old swallow-tailed kites observed in flocks by 4 observers from 23 March to 31 May 1996.

Total

Observer

>1-year old

Yearling

1 2 3 4

91 136 118 142 487

3 7 5 5 20

# Unknown 22 4 6 2 34

Yearling/ >1-year old 0.033 0.052 0.042 0.035 0.041

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the counts to show a higher proportion of yearlings than the observations of radio-tagged birds, since yearlings from outside the region would immigrate into the area and replace those that disperse out (in contrast, we do not detect radio-tagged birds from other regions). We do not yet know enough to comment on the relative likelihood of the other 3 possible explanations (dispersal, sampling error, mortality). Age of First Breeding (Objective 2) Observations of the 1995 yearlings in 1996 were our first opportunity to determine if 1-year-old kites still have a short tail, as do young of the year prior to their first fall migration. The 1995 yearlings had tails that were longer than those of birds that have recently fledged (young of the year), but their tails were still short enough to distinguish them from the long-tailed kites that breed. The same was true of the 4 1996 yearlings observed in 1997. None of the 3 1995 kites and none of the 4 1996 kites showed signs of nesting during the time that they were observed as yearlings, and all of the breeding kites at the 268 nests monitored through 1996 had long tails. We conclude that most swallow-tailed kites do not breed at 1 year of age. Behavior as Sub-adults (Objective 2) Because the 7 1-year-olds that we detected ranged so widely and did not remain in any single place for long, we were unable to make detailed observations of their behavior. We are confident, however, that none of these birds nested. The other distinguishing behavior was the fact that they covered such large areas with no apparent adhesion to a defined activity range. In 1997, the first year in which we tracked radio-tagged kites from the air in northern Florida, 2 of the 4 yearlings and the single 2-year-old that we detected were found in northern Florida in early June after apparently being absent during our flights in the north and south in May. We never detected the 2-year-old again, but the 2 yearlings gradually moved southward through peninsular Florida until we last located them in August. It is possible that at least some yearlingsâ&#x20AC;&#x201D;perhaps 1 sexâ&#x20AC;&#x201D;travel widely with no attachment to specific sites, after arriving back in the U.S. following their first spring migration. Our results suggest that they may move long distances northward early in the season, then gradually move southward through Florida. Migration (Objectives 6, 7, and 8) Routes and Timing of Migration.â&#x20AC;&#x201D;The PTTs switched to their 2-day duty cycle in late July 1996, as programmed, and the first location received was for adult #16082 in Cuba. We subsequently received useable location

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

data for 6 of the 7 kites tracked by satellite. The exception was #5394, the last kite we radio tagged. The small amount of information received from this radio suggested that it was transmitting from the ground or even below the surface of shallow water somewhere within 3 km of the juvenile’s nest, perhaps because the kite had died or shed the PTT. The number of useable locations (i.e., sufficiently accurate) varied among the 6 kites but totaled 69 (Table 14). Although the last useable locations for #16082 and #16083 were in late August, both continued to move and to be detected (with poor accuracy, which precluded inclusion in the analysis) until late September. As the PTTs shifted to longer duty cycles in September (from 2-day to 7 day) and again in November (from 7-day to 30-day), the number of useable locations continually decreased (see Satellite Radio Tagging and Tracking in Methods). For some of the PTTs (e.g., #16082 and #16083) this eventually resulted in complete loss of contact. No locations were obtained for any of the 6 kites after late November, soon after the PTTs shifted to a 30-day duty cycle. They were programmed to change to a 4-day cycle in mid-February, if battery levels permitted, to provide some information on northward migration. The batteries apparently were exhausted by then because we never received more data. The 4 adults and 2 juveniles provided 26 useable locations in Mexico and Central America (Fig. 9). They lingered or moved very slowly for several days soon after crossing the water. One of the 2 kites detected in Cuba spent at least 7 days there before flying to the Yucatan Peninsula. All the birds passed slowly through a narrow corridor along the east coast of southern Quintana Roo, Mexico, and Belize, using barrier islands and, in 2 cases, even heading back to the north for brief periods. They moved quickly through Honduras, Nicaragua, and Costa Rica, but slowed down again in Panama.

Table 14. The number of useable locations for each satellite radio-tagged kite and dates of the first and last detections (69 total locations). PTT #

Kite

16081 16082 16083 16084 16085 16086

Adult A-3 Adult M-24 Adult SM Adult C-2A Juvenile SMJ Juvenile C-2J

# Locations 13 8 8 15 11 14

First location

Last location

30 July 1996 28 July 1996 17 September 1996 1 August 1996 1 August 1996 7 August 1996

21 November 1996 27 August 1996 30 August 1996 28 October 1996 25 September 1996 23 November 1996

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. 9. Migration locations (n = 26) for 2 juvenile and 4 adult swallow-tailed kites tracked by satellite from their nesting areas in Florida (indicated by star), 28 Julyâ&#x20AC;&#x201C;18 September 1996.

No concentrations of migrating swallow-tailed kites, even in small numbers, were ever reported anywhere along this route. People have remarked that very few are seen during the spring and fall in the Florida Keys and Cuba, and migration observers near Vera Cruz, Mexico, have seen fewer than 100 per year, compared with 47,000 Mississippi kites (Ictinia mississippiensis) (E. Ruelas, Pronatura, Veracruz, Mexico, personal communication). One possible explanation is that the small U.S. population of swallow-tailed kites migrates early and in small groups, thus reducing the chances of detection. Useable satellite locations in South America for 3 adults and 1 juvenile are shown in Fig. 10. Two other kites, #16082 and #16085, did not provide useable locations beyond late August, when they were still in Central America.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

All 4 kites that reached South America turned south when they reached the Andes in western Colombia, staying within the Pacific coastal plain through the Choco region and crossing the Andes near Pasto, Colombia. The mountains are narrower there than at any other point in their entire length, and there is an obvious pass near the city (personal observation). The open-circle fix (#16083) in southwestern Colombia is in this pass. Colombian ornithologists are not aware of any concentrated flights of migrant raptors in this area, but they conceded that such flights might occur but go unnoticed.

Fig. 10. Satellite and VHF transmitter locations for 3 adult and 2 juvenile swallow-tailed kites on their 1996 southbound migration and on their winter range in South America.

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Adult #16083 was not detected after crossing the Andes on 17 September 1996. The 2 adults and 1 juvenile that we tracked east of the Andes followed a narrow, direct route southeastward (Fig. 10). All 3 kites had very similar paths, despite the fact that they passed successive points from 14 to 24 days apart. They apparently were not influenced by each otherâ&#x20AC;&#x2122;s movements or by the same local weather systems as they moved southeastward. Both adults gradually slowed down. Overall, #16084 averaged 85 km per day and #16081 averaged 81 km per day. Movements of #16084, the bird for which we have the most locations, illustrate changes in the rate of travel as adults progressed southward (Figs. 11

Fig. 11. Satellite-derived locations (circles) in Central America with dates for swallow-tailed kite adult #16084 during southbound migration in 1996. Star indicates nest area in the Big Cypress Swamp, Florida.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

and 12). The first useable fix was on 1 August, when the kite was already in northern Belize. Within 5 days, it was in southern Nicaragua, then Panama, and it probably crossed into Colombia a few days later. On 19 August #16084 was on the eastern slope of the Andes, just north of the border between Colombia and Ecuador. It next moved south, then traveled steadily southeastward near the southern border of Brazil. The rate of travel for #16084 ranged from at least 204 km per day in Belize and Honduras to 24 km per day in Brazil.

Fig. 12. Satellite-derived locations (circles) in South America with dates for swallow-tailed kite adult #16084 during southbound migration in 1996.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

The single satellite-tracked juvenile in Fig. 10 is #16086, the offspring of kite #16084. On 21 October, juvenile #16086 came within 25 km of an area used by its parent 13 days before; on 3 November, #16086 came within 70 km of where its parent had been 6 days before (Fig. 4). Kite #16086 left Florida over a month after #16084, but made up most of that time by traveling faster. It averaged 149 km per day from Cuba to Brazil, versus 85 km per day for its parent. Even though juveniles seemed to take a long time to begin their first over-water flight from Florida, they apparently are capable of rapid movements comparable to those of adults. Wintering Destinations.â&#x20AC;&#x201D;Our objective was to determine the most likely wintering areas for Floridaâ&#x20AC;&#x2122;s swallow-tailed kites based on the distribution of the satellite-derived locations once the radio-tagged kites appeared to settle in on their winter range in late 1996. Then, a trip to 1 or, perhaps, 2 specific areas would be planned to examine habitat conditions and search for our radiotagged juveniles carrying conventional VHF radio-transmitters. We expected both the migration corridor and the ultimate destinations to be more widely distributed than they actually were. We also expected the kites to reach their winter range sooner than they did, well before the PTTs would shift to their 30-day duty cycle, effectively turning them off for the winter. Travel plans were made accordingly. The 3 kites for which we continued to receive useable signals did not stop moving southeastward until mid-November, after Arnett and Washburn began their fieldwork near Cuiaba in the state of Mato Grosso, Brazil. We searched visually just to the north and northwest of the Pantanal (Fig. 10) for aggregations of kites and scanned for VHF radio-signals from juveniles tagged in Florida during 1995 and 1996. The radio-tagged kites all were either approaching or had just passed through this area when our fieldwork began on 7 November. From there, ground and aerial searches proceeded southeastward, around the eastern side of the Pantanal, through the states of Mato Grosso, Mato Grosso do Sul, and Parana, into southernmost Brazil. At the end of their trip, Arnett and Washburn extended the search area northwestward into the state of Rondonia, where 1 satellite-tagged kite remained, continuing to move very slowly southeastward into early December. What few satellite locations we had for the kites near the southern terminus of their migration suggested that they were using the slightly elevated landscape adjacent to broad areas of lowland forest and very extensive freshwater marshes, so we confined our search effort to these more upland areas. In all, our ground and aerial searches covered a narrow crescentshaped area about 1,800 km long and 400 km wide curving southeast to southward from Pimenta Bueno, Rondonia, to Curiuva, Parana. About 12% of

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

this 1,800-x-400-km area was searched during 5 aerial tracking sessions from 11 to 26 November. Ground effort combined visual searches from roads with scanning telemetry searches from roadsides and available elevated sites for VHF signals from kites tagged in Florida and Louisiana. When young of the year began migrating from our Florida study population in August and September, at least 26 of the 35 radio-tagged kites were alive. A separate study, conducted in southern Louisiana by Jennifer Coulson, radio tagged 9 young of the year in 1996, an unknown number of which survived to migrate southward. Our telemetry surveys, therefore, scanned for a total of 35 frequencies, 26 from Florida and 9 from Louisiana (as noted in Methods, satellite transmitters cannot be located or tracked with any type of portable receiving equipment equivalent to what is used with VHF transmitters). Given the very large size of the search area, the small number of radiotagged kites, the relatively small area searched from the air (12% of winter range), and the constraints on radio tracking (e.g., limited signal range from the ground, very high flying costs of US$250–US$350 per hour, radio interference, failures of aerial navigation equipment), the probability of detecting VHF signals was small. Any information for VHF-tagged juveniles, however, would augment our limited data from the satellite transmitters and contribute to our understanding of swallow-tailed kite wintering range and behavior. Locations of VHF-tagged Kites.—Arnett and Washburn located 4 VHFtagged juveniles, 3 from our Florida study population (#s 414, 516, and 691) and 1 (#492) from Jennifer Coulson’s study area near the Pearl River in southern Louisiana. Locations of VHF-tagged kites are shown with small closed circles in Fig. 10. The Louisiana kite was found just north of the Parana River in Mato Grosso Do Sul, within 20 km of a point occupied by satellite-tracked juvenile #16086 (from a nest in the northern part of Big Cypress National Preserve, Collier County) 3 days before. Kite #414 was found about 180 km west of there, within 35 km of a point where satellite-tracked adult #16084 was detected 22 days before. The other 2 VHF-tagged juveniles were found about 45–90 km north of Cuiaba, Mato Grosso, within about 80 km of each other and near the presumed route (around the eastern perimeter of the Pantanal) of the 4 kites (#s 16084, 16086, 414, and 492) that were found farther south. Fieldwork in Brazil coincided with the early part of the nesting cycle of the southern subspecies. Arnett and Washburn observed territorial and courtship behaviors typical of nesting kites observed in Florida and located 2 active nests. One of the VHF-tagged juveniles (#691) was associating with a group of 5 other kites that included the pair at one of these nests; it was the only yearling in the group.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Wintering Habitats.â&#x20AC;&#x201D;Swallow-tailed kites were not uniformly observed in the 1,400-x-350-km search area. In fact, no kites were observed in vast portions of the area. The greatest concentrations were in southern Mato Grosso Do Sul, southwestern Mato Grosso, and southeastern Rondonia. Radio-tagged kites occupied both of these areas, but the large size of many of the flocks suggested that they contained individuals from the northern (i.e., U.S.) and southern subspecies. We tentatively estimated that the area in Brazil occupied by the U.S. population of swallow-tailed kites during the boreal winter measures about 1,400 x 350 km, or 490,000 km2 (Fig. 10). The conservation focus in this region is dominated by international interest in the Pantanal, a vast freshwater marsh system near the Bolivian border that is more than 500 km from north to south. The greatest threats to the ecological health of the Pantanal stem from large-scale agricultural development and the related pollution occurring in more elevated terrain mainly to the east and south. It is this more upland landscape surrounding the Pantanal that was occupied by the radio-tagged swallow-tailed kites. Specific natural habitats used by the kites consisted mostly of cerrado, a xeric community dominated by scattered small trees and shrubs, and the associated gallery forest, which consists of taller trees along riparian courses (Sick 1993). The kites also used fazendas, or ranches and farms with relatively low-intensity uses, within landscapes that were historically cerrado and gallery forest. The numbers of kites seen in association with these lowintensity agricultural sites suggests that this land use is compatible with the conservation of swallow-tailed kites. It is apparent, however, that the far more intensive types of agricultural development that are rapidly expanding throughout the region (Cochrane et al. 1985, Alho et al. 1988, Por 1995) will not allow swallow-tailed kites to persist, whether as wintering birds (the northern subspecies) or as breeders (the southern subspecies). The most dramatic example of this was in the state of Parana. The only band returned to the U.S. Geological Surveyâ&#x20AC;&#x2122;s Bird Banding Laboratory for a swallow-tailed kite was from a bird banded in the Florida Keys in 1965 and shot later that year near Curiuva, southeast of Londrina. Aerial and ground searches in Parana failed to detect any swallow-tailed kites, radio-tagged or otherwise, and none of the satellite-tracked kites wintered that far southeast. The reason was obvious: intensive agriculture had replaced virtually all the native vegetation, despite a federal statute that 20% of the latter must be conserved. Local residents indicated that most of the conversion to agriculture had occurred in the last 40 years.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Communal Roosts.â&#x20AC;&#x201D;Two of the VHF-tagged juveniles led to the discovery of 2 large communal roosts. On the morning of 22 November 1996, kite #414 was found in a roost of at least 1,400 swallow-tailed kites, and on 1 December, #516 occupied a roost of about 300. In each case, these kites were the only radio-tagged birds in the roost. It is possible that many of the kites in these roosts were of the southern subspecies, but such large roosts have never been observed in Florida while kites were nesting and young were still dependent. The 2 nests found in Brazil still had nestlings when the large roosts were discovered, 3 months before swallow-tailed kites were due back in Florida for the next breeding season. Critical Areas and Potential Threats.â&#x20AC;&#x201D;Virtually none of the land in the wintering range or anywhere along the migration corridor was in public ownership. The specific areas within the winter range that were most intensively used by swallow-tailed kites were large (several thousand hectares), well-established ranches that had been in single-family ownership for many years. The ranches where most of the kites concentrated had relatively large patches of native forest and savannah remaining and consisted of a relatively diverse array of plant communities compared with the adjacent agricultural lands dedicated to row crops, mainly soybeans. The ranchers we contacted were interested in learning about the kites, the importance of these sites, and the likelihood that this indicated high biodiversity and conservation value for their land. Without exception, we were welcomed and encouraged in our work and were often assisted logistically. Large parcels of land with relatively high proportions of diverse native forest habitats have high value for migrant and resident swallow-tailed kites in this region. Large family ranches that were productive without being overly intensive were serving this need. Communal roost sites, furthermore, have especially high importance based on habitual use by large numbers of kites. The 2 largest roosts we found, used by well over 2,000 kites, were on large family-owned ranches. Unfortunately, the policies of 2 prominent federal agencies conflict by promoting intensive agricultural uses while discouraging the clearing of native plant communities. The federal natural resource and environmental regulatory agency (IBAMA), enforced a policy whereby farms and ranches must maintain native forest on at least 20% of the land, plus a minimum-width corridor of riparian habitat. In the case of Fazenda Campana, site of the >1,400-kite communal roost, this represented 29% of the total area of the

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

ranch. Because the owners of this ranch, Antonio and Arthur Barbosa de Souza, had carefully managed their land for many years for both agricultural and wildlife values, they already met these requirements. Landowners who were not in compliance had 30 years to produce the required amount of forest. Clearly, this is good environmental and conservation policy on a scale that will assure tangible benefits. We learned from legislative and organization officials that the Brazilian government will strictly enforce the law. On the other hand, however, the federal agricultural ministry has a longerstanding policy of taxing agricultural lands in negative proportion to productivity. Thus, landowners whose yields decline are subject to greater taxes, exacerbating an already threatening financial situation and forcing them to convert remaining native habitats to productive farm land. The landowners obviously feel they are victims of this conflict with no apparent resolution. One response is to manage for livestock more intensively on unforested areas that presently retain enough natural vegetation to provide both wildlife habitat and forage for livestock. Unfortunately, this solution does not favor wildlife. One can imagine resolutions to this conflict, including realignment of government policy; enhanced management of native rangelands that maintains both wildlife and livestock forage values; and expanded, revenue-producing uses of wild areas within ranches and other agricultural areas, such as carefully designed ecotourism opportunities, that could offset the costs of restricted agricultural productivity. Presentations The following papers, based on work described in this report, were presented at professional meetings from 1995 to 1998. Depressed Success of American Swallow-tailed Kites (Elanoides forficatus) Nesting in Introduced Australian Pines (Casuarina spp.). K. D. Meyer, D. J. Duvall, and J. E. Arnett. Presented November 1995 at the annual meeting of the Raptor Research Foundation. Estimating Annual Productivity at a Large Premigration Communal Roost of American Swallow-tailed Kites (Elanoides forficatus). K. D. Meyer. Presented October 1995 at International Partners in Flight conference.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Age-class Distinctions and Delayed Reproduction of American Swallow-tailed Kites in Florida. Kenneth D. Meyer and J. E. Arnett. Presented August 1996 at the joint meeting of the American Ornithologistsâ&#x20AC;&#x2122; Union and the Raptor Research Foundation. Fall Movements of Swallow-tailed Kites Determined from Satellite Telemetry. K. D. Meyer. Presented October 1996 at the joint meeting of the Association of Field Ornithologists and the Georgia Ornithological Society. Migration Routes and Winter Range of the Swallow-tailed Kite (Elanoides forficatus) Based on Satellite and VHF Telemetry. K. D. Meyer, J. E. Arnett, and A. W. Washburn. Presented October 1997 at the annual meeting of the Raptor Research Foundation. The Trans-equatorial Migration of the Swallow-tailed Kite (Elanoides forficatus forficatus) Based on Satellite and VHF Telemetry: Route, Habitat Affinities, and Implications for Conservation. K. D. Meyer, A. W. Washburn, and J. E. Arnett. Presented April 1998 at the North American Ornithological Congress.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

IMPLICATIONS FOR CONSERVATION AND MANAGEMENT 1. We made important progress in developing methods for studying demography, dispersal, and migration biology of swallow-tailed kites. This includes techniques for nest-searching, trapping and marking, VHF radio tracking, and applying satellite tracking to answer questions about year-round movements, habitat use, and threats. 2. This was our first opportunity to compare basic features of swallow-tailed kite biology over the length of the Florida peninsula. Nesting success, juvenile survival (post-fledging and first-year), and the extent and character of juvenile dispersal were similar from north to south despite differences in the vegetation landscape and nesting phenology from north to south. 3. Nesting effort and success throughout Florida apparently were related to weather. Unusually low or high surface water conditions in the spring appear to influence nesting effort and success. Post-fledging survival (up to the time of migration) has been consistent at about 75% across years and throughout Florida. First-year survival, however, may be poor based on our inability to re-locate more than 20% of VHF radio-tagged kites at 1 and 2 years old, despite very thorough search coverage. We obtained similar results with an alternative survey method, unrelated to radio telemetry, consisting of counts of the relative numbers of 1 year-old and older kites (based on plumage differences). Alternative explanations for the low return rate include longrange dispersal within the U.S. and the possibility that some subadults remain in Latin America until they are ready to breed when they return to the U.S. Population models of long-lived birds usually indicate that trends are particularly sensitive to adult survival. If, however, juvenile survival is this low, as it appears to be for Florida’s kites, it could be an important factor in reducing recruitment and limiting the population. Age of first reproduction is another important variable when modeling population trends. In addition to examining survival, we determined that most swallow-tailed kites probably do not attempt to breed before at least 3 years of age. As our samples for estimating demographic parameters increase, so does our ability to identify limiting factors and predict trends for Florida’s population of swallow-tailed kites.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

4. The radio-tracked juveniles exhibited 1 of 2 general strategies for post-fledging/pre-migration dispersal. Some remained within 3â&#x20AC;&#x201C;10 km of their natal area until the onset of migration, while others left their natal areas beginning at about 2 weeks after fledging and occupied areas well beyond 120 km. There was some suggestion that these strategies may have been related to sex, with females showing more of a tendency to range more widely, but our data did not reveal a strong relationship in this regard. It was clear, however, that post-fledging movements were greater in years or in specific breeding areas where conditions were less than optimal for nesting, as indicated by below-average breeding effort and perhaps nesting success. Although our opportunities to study dispersal behavior among 1- and 2-year-old kites were limited by small samples, the pattern was very similar to that observed for young of the year: close adherence to the natal area or wide-ranging movements of hundreds of kilometers. The latter behavior seemed to prevail for kites >1 year old. For all subadults, however, there always was some period of association with their natal area, at least for part of the breeding season. This reinforces previous conclusions about the importance of habitually used nesting neighborhoods by groups of swallowtailed kites and the need to consider the speciesâ&#x20AC;&#x2122; pervasive social behavior in planning for their management and conservation. Coastal-plain river systems clearly serve as magnets for nesting, roosting, and dispersing swallow-tailed kites in the southeastern U.S. (Meyer 1995, Meyer and Collopy 1995). Habitually used nesting concentrations in the Florida peninsula are associated with a wider variety of landscapes, but they are equally persistent and some support substantially higher densities of nesting kites (Meyer and Collopy 1995). Given the range of movements of kites that are not tied to specific nesting areas (either as subadults or late in the nesting season), managing for dispersal habitat is not feasible or advisable. Extended nesting areas and habitually used roost sites, however, deserve attention. 5. The larger the pre-migration communal roost, the more likely it will be consistently used from year to year. Roosts provide an uncommonly good opportunity for tracking population trends. These topics are addressed more thoroughly elsewhere (Meyer 1998). The known large roosts should be monitored, and additional ones should be searched for as resources permit. VHF radio-tracking is especially useful for discovering communal roosts.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

6. The present study was the first attempt to investigate the biology and conservation needs of Florida’s swallow-tailed kites beyond the state, where this breeding population spends at least half its year. We identified areas of potential risks along the migration pathway, particularly related to crossing water from Florida to the Yucatan Peninsula and crossing the Andes in northwestern South America. Some portions of the migration corridor are very narrow, such as in eastern Central America, and habitat degradation may be of particular importance in these areas. Cuba, the Yucatan Peninsula (Mexico), and Belize stand out as possibly critical stopover areas where the integrity of the natural landscape and human interference could play an important role in kite conservation. The most significant aspect of our migration study, however, was discovering the spatially concentrated winter range of the Florida (and probably U.S.) population of swallow-tailed kites on a small number of unprotected, privately owned cattle ranches in south-central South America. The sites supporting the densest concentrations of wintering kites should be the focus of immediate management attention. Regions and specific areas critical to migrating swallow-tailed kites probably are equally important to other species of migratory birds (Hagan et al. 1992, Rappole 1995). This adds to the justification for conservation action in these areas and increases the value of whatever protection can be accomplished. The migration study should be continued to illuminate additional critical sites and passage points, sources of mortality, management needs, and conservation opportunities. 7. The swallow-tailed kite’s predominant year-round dependence on privately owned lands is a central issue to the species’ conservation. We should be aggressive and creative in finding management alternatives to acquisition of critical habitat, including conservation easements, cooperative management agreements, and landowner incentives. 8. Rangewide threats to Florida’s population of swallow-tailed kites are difficult to identify and manage. The best long-term strategy for conservation is to continue investigating limiting factors and emerging threats, to determine where intervention can assert the most influence, and to plan management action accordingly.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

LITERATURE CITED Alho, C. J. R., T. E. Lacher Jr., and U. C. Goncalves. 1988. Environmental degradation in the Pantanal ecosystem. BioScience 38:164–171. Cely, J. 1979. Status of the swallow-tailed kite and factors affecting its distribution. Pages 144–150 in D. M. Forsythe and W. B. Ezell Jr., editors. Proceedings of the first South Carolina endangered species symposium. South Carolina Wildlife and Marine Resources Department, Columbia, South Carolina, USA. Cochrane, T. T., L. G. Sanchez, L. G. de Azevedo, J. A. Porras, and C. L. Garver. 1985. Land in tropical America: guide to climate, landscape, and soils for agronomists in Amazonia, the Andean Piedmont, Central Brazil, and Orinoco. Centro Internacional de Agricultura Tropical, Cali, Colombia, and Empresa Brasileira de esquisa Agropecuaria, Centro de Pesquisa Agropecuaria dos Cerrados, Planaltina, D. F. Brasil. Hagan, J. M., III, and D. W. Johnston, editors. 1992. Ecology and conservation of Neotropical migrant landbirds. Smithsonian Institution Press, Washington, D.C., USA. Hunter, W. C., L. Peoples, and J. Collazo. 2001. Partners in Flight bird conservation plan for the South Atlantic coastal plain. American Bird Conservancy, The Plains, Virginia, USA. Meyer, K. D. 1995. Swallow-tailed kite (Elanoides forficatus). In A. Poole and F. Gill, editors. Birds of North America, No. 138. Academy of Natural Sciences, Philadelphia, Pennsylvania, USA, and American Ornithologists' Union, Washington, D.C., USA. _____. 1998. Communal roosts of the American swallow-tailed kite in Florida: habitat associations, critical sites, and a technique for monitoring population status. Final report. Florida Game and Fresh Water Fish Commission, Tallahassee, Florida, USA. _____, and M. Collopy. 1995. Status, distribution, and habitat requirements of the American swallow-tailed kite (Elanoides forficatus) in Florida. Final report. Florida Game and Fresh Water Fish Commission, Tallahassee, Florida, USA.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

_____ and _____. 1996. American swallow-tailed kite. Pages 188–196 in J. Rodgers, editor. Rare and endangered biota of Florida. Volume 5: Birds. University Press of Florida, Gainesville, Florida, USA. Millsap, B. 1987. Summer concentrations of American swallow-tailed kites at Lake Okeechobee, Florida, with comments on post-breeding movements. Florida Field Naturalist 15:85–92. _____, J. Gore, D. Runde, and S. Cerulean. 1989. Setting priorities for the conservation of fish and wildlife species in Florida. Florida Game and Fresh Water Fish Commission, Tallahassee, Florida, USA. Por, F. D. 1995. The Pantanal of Mato Grosso (Brazil). Kluwer Academic Publishers, Dordreht, The Netherlands. Rappole, J. H. 1995. The ecology of migrant birds. Smithsonian Institution Press, Washington, D.C., USA. Robertson, W., Jr. 1988. American swallow-tailed kite. Pages 109–131 in R. S. Palmer, editor. Handbook of North American birds. Volume 4. Yale University Press, New Haven, Connecticut, USA. Sick, H. 1993. Birds in Brazil. Editoria Universidade de Brasilia, Brazil.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

Appendix A. Post-fledging/pre-migration movements of juvenile (young of the year) swallow-tailed kites tracked in Florida by VHF radio telemetry in 1996. Each map’s legend provides the kite’s identification number, the range of dates for the locations, and dates of occupancy in communal roosts (where available). The following symbols and information are common to all of the maps. Star – Nest site.

Dot – Telemetry-determined location.

Solid line – Known route of travel.

Dashed line – Connects successive radio locations when the intervening

route was unknown. R – Associated dot or star indicates a communal roost occupied by the radio-tagged kite. Dates – Indicate successive movement and provide a time reference. Not all location dates are included. Range of dates for a single dot – The kite was at that location every time it was detected; it does not mean that the bird necessarily stayed at that location for the entire time. Circle – General area of about 15-km diameter in which a kite was repeatedly detected on the dates noted. Arrow – Indicates direction of movement.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. A-1. Nest locations of 1996 radio-tagged kites that died within a few weeks of fledging and within several kilometers of their nests. They were monitored during the following periods, ending with the date on which the bird was confirmed dead: #382, 16 May–10 June; #474, 22 May–6 June; #577, 28 May–18 June; #655, 13–19 June; #667 and #706, 29 May–19 June; #779, 8–23 June; and #807, 9 June–30 July.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. A-2. Radio-tagged swallow-tailed kite juveniles #396 and #414 remained within the circled area from 20 May to 12 August 1996. Kite #414 was found in Brazil November 1996, in Florida June 1997, and in Brazil December 1997; #414 roosted with 12 other kites within the circle on 20 July 1996.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. A-3. Movements of radio-tagged swallow-tailed kite juveniles #427 and #441 from 22 May to 12 August 1996. These kites roosted (R) at the CREW site on 28 July and from 7 to 12 August. Kite #414 was found dead on 12 August 1996.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. A-4. Movements of radio-tagged swallow-tailed kite juveniles #459 and #488 from 22 May to 7 August 1996. These kites roosted (R) at the CREW site on 28 and 29 July and 6 August 1996. Kite #488 also was found in that roost on 15 August.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. A-5. The following radio-tagged swallow-tailed kite juveniles remained within the circled area during the specified periods: #503 from 22 May to 8 August, #516 from 26 May to 18 August, and #547 from 24 May to 12 August 1996. Kite #547 roosted within the circle with 23 other kites on 18 July 1996 and with 12 other kites on 26 and 27 July and 1 August 1996. Kite #503 roosted within the circle with 11 other kites on 20 July 1996. Kite #547 was found dead in mid-August 1997.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. A-6. Radio-tagged swallow-tailed kite juvenile #557 remained in the circled area from 25 May to 7 July 1996.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. A-7. Radio-tagged swallow-tailed kite juvenile #596 remained in the circled area from 26 May to 8 July 1996.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. A-8. Movements of radio-tagged swallow-tailed kite juvenile #623 from 26 May to 12 August 1996.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. A-9. Movements of radio-tagged swallow-tailed kite juvenile #636 from 28 May to 23 August 1996. The northern roost, in the Devilâ&#x20AC;&#x2122;s Garden area, was used by #636 on 2, 9, 12, and 20 August 1996; the southern roost, in northern Big Cypress National Preserve, was used on 8, 10, 12, and 18 July 1996.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. A-10. Movements of radio-tagged swallow-tailed kite juvenile #687 from 20 May to 19 August 1996. Kite #687 roosted (R) at the large Corkscrew Swamp roost from 6 to 19 August 1996.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. A-11. Movements of radio-tagged swallow-tailed kite juvenile #691 from 29 May to 12 August 1996. We found this bird in Brazil in November 1996.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. A-12. Movements of radio-tagged swallow-tailed kite juvenile #713 from 30 May to 28 August 1996. Kite #713 used the indicated roost site (R) on at least 9 nights from 1 to 26 August 1996.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. A-13. Movements of radio-tagged swallow-tailed kite juvenile #727 from 31 May to 26 July 1996.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. A-14. Movements of radio-tagged swallow-tailed kite juvenile #733 from 31 May to 13 August 1996. Kite #733 roosted (R) at the large Lake Okeechobee roost on at least 6 nights from 22 July to 13 August 1996.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. A-15. Movements of radio-tagged swallow-tailed kite juvenile #744 from 2 June to 9 September 1996.

Kite #744 occupied the Lake Okeechobee roost site (R) 26, 27, and 28 August 1996. The roost to the south

(R) was used on 2, 5, 9, 12, 16, and 20 August 1996.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. A-16. Movements of radio-tagged swallow-tailed kite juvenile #753 from 6 June to 28 August 1996.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. A-17. Movements of radio-tagged swallow-tailed kite juvenile #760 from 6 June to 5 August 1996. Kite #760 roosted at Lake Okeechobee on 2 August 1996.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. A-18. Movements of radio-tagged swallow-tailed kite juvenile #770 from 7 June to 2 September 1996.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. A-19. Radio-tagged swallow-tailed kite juvenile #790 remained in the circled area from 7 June to 22 July 1996.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. A-20. Radio-tagged swallow-tailed kite juvenile #801 remained in the circled area from 8 June to 31 July 1996.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. A-21. Movements of radio-tagged swallow-tailed kite juvenile #805 from 8 June to 13 September

1996. Kite #805 roosted at Lake Okeechobee on 15, 18, 23, and 27 August 1996.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. A-22. Movements of radio-tagged swallow-tailed kite juvenile #824 from 11 June to 8 August 1996. Kite #824 roosted in Everglades National Park with 15 other kites on 11 August 1996.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. A-23. Movements of radio-tagged swallow-tailed kite juvenile #831 from 14 June to 20 August 1996. Kite #831 roosted at Lake Okeechobee (R) on 13, 14, 15, 18, 20, and 26 August 1996 and at the more southerly roost (R) on 9 August 1996.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATION—Meyer

Appendix B. Post-fledging/pre-migration movements of juvenile (young of the year) swallow-tailed kites tracked in Florida by VHF radio telemetry in 1997. Each map’s legend provides the kite’s identification number, the range of dates for the locations, and dates of occupancy in communal roosts (where available). The following symbols and information are common to all of the maps. Star – Nest site.

Dot – Telemetry-determined location.

Solid line – Known route of travel.

Dashed line – Connects successive radio locations when the intervening

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. B-1. Movements of radio-tagged swallow-tailed kite juvenile #901 from 29 May to 19 August 1997. Roost site (R), which was used at least on 22 July, 10 August, and 11 August with as many as 20 other kites, was on Little Lake George.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. B-2. Movements of radio-tagged swallow-tailed kite juvenile #871 from 7 June to 4 September 1997.

Roost site (R) was near the Wekiwa River in Rock Springs Run State Preserve. Kite #871 roosted there

with other kites on 16, 17, 23, and 24 July 1997.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. B-3. Movements of radio-tagged swallow-tailed kite juvenile #857 from 4 June to 25 August 1997. Roost site (R), which was used repeatedly, was near #857â&#x20AC;&#x2122;s nest in Big Gum Swamp, Osceola National Forest.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. B-4. Movements of radio-tagged swallow-tailed kite juvenile #850 from 23 May to 19 August 1997.

Roost sites (R) were on the Seven Sisters Islands and Stokes Island on 26 July and 2, 3, and 9 August 1997.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. B-5. Movements of radio-tagged swallow-tailed kite juvenile #835 from 9 June to 27 August 1997. Roost site (R) was occupied simultaneously by kite #805 and 11 other kites on 21 July 1997.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. B-6. Movements of radio-tagged swallow-tailed kite juvenile #805 from 9 June to 25 August 1997. Roost site (R) was occupied simultaneously by kite #835 and 11 other kites on 21 July 1997.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. B-7. Movements of radio-tagged swallow-tailed kite juvenile #706 from 16 June to 28 August 1997.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. B-8. Movements of radio-tagged swallow-tailed kite juvenile #473 from 27 June to 27 August 1997.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. B-9. Radio-tagged swallow-tailed kite juvenile #316 remained in the circled area from 22 June to 8 August 1997.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. B-10. Movements of radio-tagged swallow-tailed kite juvenile #100 from 23 May to 19 August 1997. Roost site (R) was in the Green Swamp Wildlife Management Area, near the Withlacoochee River. Kite #100 roosted there with 20 other kites, including #759, on 15 July 1997.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. B-11. Movements of radio-tagged swallow-tailed kite juvenile #759 from 23 May to 19 August 1997.

This kite used 2 roost site, both near R, in the Green Swamp Wildlife Management Area, near the

Withlacoochee River. Kite #759 roosted there with 20 other kites, including #100, on 15 July 1997; and on

12, 14, 17, and 18 August with about 30 other kites.

SWALLOW-TAILED KITE DEMOGRAPHY, DISPERSAL, MIGRATIONâ&#x20AC;&#x201D;Meyer

Fig. B-12. Movements of radio-tagged swallow-tailed kite juvenile #750 from 2 June to 14 July 1997.

FLORIDA FISH AND WILDLIFE CONSERVATION COMMISSION FINAL REPORT

Fig. B-13. Nest locations of 1997 radio-tagged juvenile kites that died within a few weeks and several kilometers of their nests. They were monitored during the following periods, ending with the date on which the bird was confirmed dead: #924, 5 June–12 July; #779, 19–30 June; #877 and #886, 5–14 June; and #353, 26 June–6 August.

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