The decline of the Great White Heron in Florida by Avian Research & Conservation Institute

FINAL REPORT

FWC Grant No.:

07156

NWGP Project No.:

NG07-016

Project title:

The decline of the Great White Heron in Florida: Explanations and recommendations for recovery of this small and highly vulnerable population

Project director:

Kenneth D. Meyer, Ph.D.

Project biologists:

Peter Mahoney, B.S. Andrea Bowling, M.S. Marvin Friel, B.S. Gina Kent, M.S.

Affiliation:

Avian Research and Conservation Institute 411 N.E. 7 Street, Gainesville, Florida 32601 USA 352-514-5606, meyer@arcinst.org

Period covered:

1 July 2007 to 31 August 2010

Date submitted:

27 April 2011 (final revision)

THE DECLICNE OF THE GREAT WHITE HERON IN FLORIDA: EXPLANATIONS AND RECOMMENDATIONS FOR RECOVERY OF THIS SMALL AND HIGHLY VULNERABLE POPULATION

Date of final report: 27 April 2011 Agreement number: 07156

KENNETH D. MEYER AND GINA M. KENT Avian Research and Conservation Institute, 411 N.E. 7 Street, Gainesville, Florida 32601

THE DECLICNE OF THE GREAT WHITE HERON IN FLORIDA: EXPLANATIONS AND RECOMMENDATIONS FOR RECOVERY OF THIS SMALL AND HIGHLY VULNERABLE POPULATION

KENNETH D. MEYER AND GINA M. KENT Avian Research and Conservation Institute, 411 N.E. 7 Street, Gainesville, Florida 32601 ABSTRACT: The Great White Heron (Ardea herodius occidentalis) has a very small global distribution, the largest breeding populations have been restricted to Florida Bay and the Florida Keys. They have experienced a substantial decline during an extended period of time. The most common assumption is that fish availability has declined on the open-water mudflats and shorelines of Florida Bay and the upper Keys, tied in turn to large-scale losses of turtle grass beds. Our goal was to help explain the decline in Florida (the total US population) and to identify management and conservation actions. We examined foraging energetic, limitations of foraging habitat, dispersal and survival of juveniles, and seasonal movements and survival of adults. Foraging performance was examined with an extensive location dataset from 5 adults tracked by satellite/GPS transmitters and >3,000 direct visual observations in both Great White Heron NWR and Florida Bay. Foraging efficiency was higher in GWHNWR based on predation effort and size class of captured prey. Nesting success in GWHNWR exceeded that of Florida Bay by clear margins in both years. Young fledged per successful nest differed little in one year and was similar in the other. However, young fledged per nest was 44% higher in GWHNWR for both years combined. Tagged herons foraged with regard to tide rather than diurnal cycles, highlighting the importance of water depth in foraging decisions and performance. There was a very high degree of finely-scaled site fidelity. Core areas and the specific, repeatedly-used foraging microsites were remarkably well defined and heavily used. Average home range area was 51 square kilometers during the combined breeding and post-breeding periods with substantial overlap in the 5 ranges. Nonetheless, for 539 visually-observed foraging locations, 70% of observed herons had only 1 conspecific in close proximity and 94% had <5. While 60% of the available area consisted of continuous seagrass beds, 92% of the heron GPS locations were in this habitat type. This habitat analysis may be our most important result because it illuminates the importance not just of seagrass but of intact, expansive beds of this plant community to Great White Herons, in and out of the nesting season. The fact that patchy, discontinuous stands of seagrass do not attract herons suggests it is not the physical structure of this community that appeals to foraging Great White Herons but the more fundamentally important value of healthy, expansive seagrass beds for producing the fish on which this large bird depends. This is supported by the lower reproductive performance we documented for upper Florida Bay, where seagrass beds are more degraded. We are confident that our aerial tracking ensured a relatively high detection probability for any live birds remaining in south Florida through 2 years post-fledging. However, we obtained an unreasonably low estimate of first year survival. Natal philopatry appeared well defined during the 1 to 2 months post-fledging. Thereafter, however, there was a sudden loss of contact with nearly all of the tagged juveniles. The

iii

exceptions were 3 juveniles found during their third and fourth months post-fledging at 98, 130, and 210 kilometers north of their natal areas (and never again). Given this result, our unreasonably low estimate of apparent survival, this speciesâ&#x20AC;&#x2122; delayed sexual maturation, and anecdotal evidence of wide-ranging Great White Herons observed throughout the southeastern United States, we believe first-year birds may temporarily disperse over a broad area before returning to the south Florida breeding range at 2 to 4 years of age. The VHF transmitters we used should operate for 1-2 more years. We hope to find funding for at least one telemetry survey in south Florida during February (and March, if possible) 2011 to search for any surviving 2- and 3-year old Great White Herons that may be returning for the first time as potential breeding birds.

ACKNOWLEDGMENTS The authors thank: Peter Mahoney, Andrea Bowling, and Marvin Friel for their careful, persistent, and dedicated fieldwork under difficult conditions; Tom Wilmers, Refuge Biologist, U.S. Fish and Wildlife Service, Florida Keys National Wildlife Refuges, for information and guidance in planning this project; Tom Wilmers and Anne Morekill, Refuge Manager, U.S. Fish and Wildlife Service, Florida Keys National Wildlife Refuges, for logistical support in the lower Keys; Sonny Bass, National Park Service Biologist, Everglades National Park, for information and logistical support; Dean Demarest and Stefani Melvin, U.S. Fish and Wildlife Service Region 4 Division of Migratory Birds, and Chuck Hunter, Region 4 Chief Refuge Scientist, for securing funds for satellite/GPS telemetry; Ellie Schiller and the Felburn Foundation for additional matching support; and Stuart Cumberbatch and Michael Evans, Florida Fish and Wildlife Conservation Commission, for administering the project agreement.

INTRODUCTION Conservation Need The Great White Heron (Ardea herodius occidentalis) has a very small global distribution, limited to extreme southern Florida, coastal areas of southwestern Cuba, Puerto Rico, the Yucatan Peninsula, and coastal islands of Venezuela (Robertson and Woolfenden 1992, Stevenson and Anderson 1004, Powell 1996). The largest breeding populations have been restricted to Florida Bay and the Florida Keys. There has been much speculation and debate on the taxonomic status of the Great White Heron (Stevenson and Anderson 1994, Powell 1996), which has persisted since the American Ornithologists’ Union (AOU, 1973) assigned the subspecific rank of A. h. occidentalis. Recent genetic analysis suggests otherwise. McGuire (2001) compared microsatellite loci among Great White Herons in the Florida Keys, sympatric birds that appeared to be Great Blue Herons, and peninsular Great Blue Herons. She determined that differences between the sympatric white and blue birds were small compared with differences between the Keys population (white and blue taken together) and peninsular Great Blue Herons. McGuire (2001) concluded that the Florida Keys breeding population (white and blue combined) is distinct from other Great Blue Heron populations (e.g., peninsular Florida). Gene flow between the Keys population and peninsular Great Blue Herons probably is limited by behavioral mechanisms and ecological barriers, justifying further taxonomic investigation. McGuire (2001) argued that recruitment from Great Blue Heron populations “does not appear to be an important factor in maintaining the Great White Heron population… [thus] conservation will require understanding and managing this population as an isolate”. In Florida, where Great White Herons breed exclusively in coastal and estuarine habitats,

mainly on isolated islands, the population was thought to number at least 800 pairs in the early 1980s (Robertson and Woolfenden 1992, Stevenson and Anderson 1994). This estimate was made at the end of a 25-year period, starting in the early 1960s, when various non-systematic counts suggested a relatively stable population of at least 2,000-2,300 individuals (Powell et al. 1989), similar to Robertson and Woolfenden’s (1992) estimate of 800 pairs. This information appears to be reflected in the Great White Heron’s rank in Florida’s Comprehensive Wildlife Conservation Strategy (Florida Fish and Wildlife Conservation Commission 2005): a Species of Greatest Conservation Need with moderate status and a stable population trend (Table 6, page 63). The most recent assessments, however, paint a very different picture of the population’s status and trend. Hunter et al. (2006) identified the Great White Heron as the highest priority wading bird for management attention in the Southeast. In fact, it qualified for “Critical Recovery”, the highest action level in the Plan at both the Regional and Continental levels, due to its small population size and highly localized occurrence. For conservation purposes, the Great White Heron was treated in this U.S. Fish and Wildlife Service (USFWS) Plan as a distinct species, apart from the Great Blue Heron. The Critical Recovery designation resulted in part from recent population changes as measured by small-scale surveys (i.e., systematic but less extensive than the historic counts) in Florida Bay (Everglades National Park; S. Bass, unpublished data) and the lower Florida Keys (Florida Keys National Wildlife Refuges; T. Wilmers, unpublished data). The lower Keys component, about 25% of the Florida population, was substantially reduced in number by recent hurricanes, but limited nesting data indicate that reproductive rates generally have been good for this sub-population (Hunter et al. 2006). The larger sub-population, in Florida Bay and the lower Everglades, is exhibiting poor productivity

(Hunter et al. 2006), but the reasons are unknown. Additional evidence of poor demographic performance and decline comes from the systematic aerial wading bird surveys that have been conducted in the Everglades and Florida Bay as a cooperative, interagency effort since the 1980s (Cook and Call 2006). In the mid1990s, numbers of Great White Herons fell below 2,000 individuals and, since then, they have continued to decline (Cook and Call 2006, Figure 3, page 35). No annual count has exceeded 500 since the year 2000. This poor showing for Great White Herons is in sharp contrast with numbers of Great Egrets (Ardea alba), Great Blue Herons (Ardea herodius), and Wood Storks (Mycteria americana), which have all shown steady increases in the last 10 years; and, with the exception of the Reddish Egret (Egretta rufescens), all other species of long-legged wading birds surveyed in the study area, which appear to be experiencing slightly increasing or at least steady population levels. There is a clear consensus among managers and biologists who monitor wading bird populations in south Florida: Great White Herons stand out as a species that is experiencing a steady, substantial decline during an extended period for which other wading-bird populations are showing steady increasing trends. This recent evidence justifies revised rankings of low status and declining trend for the Comprehensive Wildlife Conservation Strategy (Florida Fish and Wildlife Conservation Commission 2005; Table 6, page 34). The cause of the Great White Heronâ&#x20AC;&#x2122;s recent decline in productivity and numbers has not been addressed. The most common assumption seems to be that food availability has declined at least in some portions of the shallow, open-water mudflats and along shorelines where the herons feed around Florida Bay and in the upper Keys. This has been tied to large-scale losses of turtle grass (Thallassia testudinum) beds in the interior of the Bay (Robblee et al. 1991), and the

resulting declines of the fish they support. Fish are the main prey of Great White Herons, particularly toadfish (Batrachoididae), Red Porgy (Pagrus spp), pipefish (Syngnathidae), and needlefish (Strongylura spp) (Stevenson and Anderson 1994). Panhandling (eating handouts from fishermen, boaters, and homeowners) is common (Powell 1983, Stevenson and Anderson 1994). In fact, Powell (1983) found that nesting success and productivity of panhandling Great White Herons exceeded that of individuals that relied on natural food supplies. There are clear correlations between high-tide levels in Florida Bay and the presence of foraging Great White Herons. Flats typically used for feeding during the coolest months, when water levels are lowest, are vacated during the summer, when water levels rise due to the expansion of the warmer water (Powell 1987). Presumably, these natural seasonal changes in prey availability are accommodated by behavioral adaptations in the herons that have evolved over time. In addition, Powell and Bjork (1990) documented movements of juveniles into interior wetland habitats of the central and southern Florida peninsula. They reported low foraging success of these young birds with resulting high mortality (90% died in these foraging areas during their first 6 months). Changes in these critical habitats could be influencing recruitment to the breeding population. The main focus of attention, however, has been on the breeding range. Most of the Great White Heronâ&#x20AC;&#x2122;s nesting areas are within the boundaries of one or two very large public conservation areas: Everglades National Park; or Florida Keys National Wildlife Refuges. Thus, nesting substrate is protected. We should be concerned, however, about hydrologic changes in the Bay resulting from decades of water management in the Everglades. It is unclear whether the population is in overall decline, or if different segments are experiencing different rates of positive and negative growth, perhaps interrelated in source/sink dynamics. How big a factor are recent hurricanes? Is the variance in reproduction and population growth for the Great White

Heron across its south-Florida range a result of altered habitat quality (Powell and Powell 1986)? In what ways does the status of the Great White Heron reflect the stresses being experienced by other species or communities due to the same perturbations? How will climate change and associated sea-level rise affect the resources on which this small population depends? What are our options for repairing or mitigating these insults in ways that will promote restoration of the Great White Heron population and the health of this sub-tropical ecosystem? Scope of the Project The goal of this study was to help explain the marked, steady decline of Great White Herons in Florida, which comprise the total continental U.S. population of this species; and to identify management and conservation actions that will reverse this trend. We describe and compare the foraging ecology and seasonal movements of Great White Herons breeding in Florida Bay and the lower Florida Keys over a 3-year period (July 2007 â&#x20AC;&#x201C; August 2010). This project was one component of a larger collaboration with the USFWS and the National Park Service that included a repeat of historic surveys in Florida Bay and the lower Florida Keys. Avian Research and Conservation Institute (ARCI) was responsible for the foraging-ecology and seasonal-movement objectives of the larger project, which are reported here. Our original proposal to the Florida Fish and Wildlife Conservation Commission (FFWCC) for the foraging and movements component included 4 objectives. However, because available funds only allowed FFWCC to cover 75% of the proposed budget, we dropped plans to address seasonal movements of adults (and a limited attempt to estimate survival). Once the project was underway, USFWS offered funding to trap adult Great White Herons and deploy 5 satellite transmitters with GPS capability. This allowed us to reinstate the fourth objective â&#x20AC;&#x201C; adult seasonal movements and survival â&#x20AC;&#x201C; to the extent possible with the limited sample size and

remaining time in the project schedule. More importantly, however, it also allowed us to address Objective 1 (Foraging energetic of breeding adults) more effectively than had been possible by following unmarked adults on forays from breeding colonies (we had not anticipated the challenges of keeping up with the outbound herons in the shallow, intervening waters). Thus, the objectives we addressed were as follows.

OBJECTIVES 1. Foraging Energetics of Breeding Adults a) Determine the spatial relationships between foraging and nesting sites. b) Quantify foraging efficiency. c) Monitor nests success and productivity; relate to foraging efficiency. 2. Is Foraging Habitat Limiting for Breeding Adults? a) Map and measure feeding territories. b) Quantify competitive and aggressive interactions of foraging herons. c) Measure the degree of habitat saturation. 3. Dispersal and Survival of Juveniles a) Describe post-fledging dispersal and measure winter ranges. b) Determine site fidelity to winter ranges. c) Estimate first-year survival (overall and by natal area). d) Determine extent of philopatry to natal areas. 4. Seasonal movements and survival of adults (Added with supplemental funds from the U.S. Fish and Wildlife Service) a) Determine post-breeding dispersal; measure summer and winter activity ranges within 1 year.

b) Estimate adult survival.

METHODS Foraging Energetics of Breeding Adults Determine the Spatial Relationships Between Foraging and Nesting Sites Adult Great White Herons were captured and fitted with 22-g (<3% of body weight) solar-powered, GPS-equipped satellite transmitters (>3-year life, Microwave Telemetry, Inc.) attached by a Teflon-ribbon harness of a proven design. The GPS component was programmed to record locations (accurate within 15 meters) at 09:00, 14:00, 16:00, 18:00, 20:00, and 22:00 hours every day when satellite coverage was optimal. Activity ranges and foraging distances were mapped to estimate foraging-range sizes using the adaptive kernel method (probabilistic, depicting core areas) using ArcGIS and ArcView with the Animal Movement extension (ESRI, Inc.) Quantify Foraging Efficiency - Foraging Great White Herons were found and observed from systematic transects (tide and weather conditions permitting) with small boats to collect foraging observational data in each study area (Florida Bay and GWHNWR). Using 8- and 10power binoculars and 15- to 40-power spotting scopes, we determined success rates for prey captures, visually estimated size classes of prey per capture, and estimated the time (in minutes, expressed as percentage of total observation time) Great White Herons spent foraging (locations over water) versus loafing or tending nests (locations over land) using the data from satellite/GPS transmitters. This analysis also determined total and relative time spent foraging during daylight and night hours. Monitor Nests Success and Productivity; Relate to Foraging Efficiency - We

systematically searched breeding colonies in Florida Bay and the lower Keys during the 2007 and 2008 breeding seasons to locate and monitor Great White Heron nests, limiting visits to 1 hour on small islands to avoid prolonged disturbance. For larger islands, which necessitated an extended stay, we maintained a steady pace to ensure that no single area was overly disturbed. The main threat was depredation of wading-bird eggs and small nestlings by avian predators, especially American Crows (Corvus brachyrynchos), which were particularly numerous at nesting colonies in Florida Bay and appeared to await the near-passage of boaters or other disturbances that might flush incubating or brooding adult waders from their nests. When a nest structure was located, we assessed activity (i.e. presence/absence of excrement and fresh vegetation) and nest stage, clutch size, number of chicks, age of chicks, tree type, nest height, and adult and nestling color morph. We flagged the nest site and recorded location data using a Garmin 12XL GPS receiver. We revisited nests until success could be determined (i.e., when at least 1 chick had fledged at >8 weeks). Visits to each nest were limited to 2 minutes. We used the R statistical software package to calculate the mean number of fledged young (MFY) for each colony based on the sub-set of successful nests and on all nests with known outcomes. Regional values for MFY, based on the sub-set of successful nests and on all nests with known outcomes, were determined in the same way. Mean clutch size was estimated from nests with known clutch size. Foraging surveys were completed in both regions by designating repeatable transects from which foraging Great White Herons could be counted. When Great White Herons were encountered during foraging surveys, we gathered data on location, foraging depth and substrate, and tide and weather info for each bird.

Is Foraging Habitat Limiting for Breeding Adults? We analyzed use of aquatic habitats for 5 adult Great White Herons tracked by satellite. All locations over land within 20 meters from aquatic edges were removed from the tracking files to focus on presumed foraging locations. We used a benthic South Florida GIS layer from the marine website (www.ocean.floridamarine.org) created by FFWCCâ&#x20AC;&#x2122;s Florida Wildlife Research Institute (FWRI), NOAA, and Miami Dade County. This layer is in the NAD 1983, Albers projection at 1 to 48,000-scale. This benthic layer file had 11 different habitat classifications (7 of which were in the study area, see Table 7) The heron GPS location data was overlain on the benthic layer in ArcGIS (ESRI, Inc) where the corresponding benthic habitat classifications were assigned. We defined and measured the available foraging area as the interior of a minimum convex polygon (MCP) produced from the distribution of all foraging locations, then generated a set of random locations equal to the number of foraging locations. We then compared the frequency of habitat use by the satellite-tracked Great White Herons to the habitats at random locations. Additional habitat information was obtained during the foraging surveys, when habitat types and approximate water depths were recorded for each heron observation. Map and Measure Feeding Territories (Defended Foraging Area - We gathered GPS location data (accurate within 15 meters) from the satellite-tracked Great White Herons, plotted all locations in ArcView (ESRI, Inc.), and used the Spatial Analyst extension (Hooge and Eichenlaub1997), to calculate the MCP and fixed kernel activity ranges for each individual. We applied a fixed-kernel analysis with unit variance and a raster resolution of 70 to create volume contours in 9 increments (10-90%). Determine the Extent of Competitive and Aggressive Interactions Between Foraging

Herons - During our feeding observations, we noted inter- and intra-specific interactions among foraging Great White Herons and Great Blue Herons. These surveys were stratified through time during the peak of nestling stage, when feeding demands are greatest for adults. All competitive interactions among Great White Herons, including threats, displacements, successful and unsuccessful pirating of food, were recorded and compared between study areas. Quantify the Degree of Habitat Saturation - After delineating the foraging areas (home ranges) of the satellite-tracked Great White Herons in ArcView GIS (ESRI, Inc), we over laid the feeding locations observed for unmarked Great White Herons during our boat surveys. To estimate the degree of habitat saturation, we calculated the number of unmarked birds found within core areas of 70, 80, and 90% of the GPS locations derived from the satellite-tracked herons. The spatial distributions of the feeding territories within an area (using the geometric centers of the fixed-kernel range depictions) were then ranked by degree of saturation. Dispersal and Survival of Juveniles Describe Post-fledging Dispersal and Measure Winter Ranges - In 2008 and 2009, we captured nestlings at 6 to 8 weeks of age and fitted them with VHF transmitters (3 to 4-year life, less than 3% of body weight, American Widlife Enterprises, Inc.) using a Teflon-ribbon harness of a proven design. Morphometrics and a small blood sample for DNA sexing were taken for all chicks and, in 2009, alpha-numeric colored leg bands were placed on all radio-tagged birds and any other nestlings older than 3 weeks that could be captured (blue with white characters in Florida Bay, red with white in GWHNWR). The radio-tagged sample was roughly split between the two study areas. Following dispersal, heron fledglings were located from the air by flying systematic search transects throughout the Florida Keys and Everglades National Park. Additional flights (to

the extent possible given budget constraints) covered broad areas of suitable habitat in central peninsular Florida. We used 2 ATS, Inc., programmable VHF scanning receivers coupled to a single pair of 3-element yagi antennas (Telonics, Inc.) mounted facing outward (left and right) on the wing struts of a Cessna 172 high-winged airplane. We programmed each scanning receiver with the VHF frequency at which each tagged heron was last detected plus an additional frequency 2 kilohertz lower and scanned continuously with both receivers (2 seconds per stored frequency), checking frequently to be certain that the receivers were not running in synchrony (i.e., we were not listening simultaneously for the same individuals in any given area). Transects were flown at 300 to 600 meters above ground level at about 160 to 170 kilometers per hour. Locations were plotted on a map and distances from natal areas were measured in ArcGIS. Determine Site Fidelity to Winter Ranges - To the extent that first-year survival resulted in sufficient locations, we planned to perform site-fidelity tests (ArcView, with Spatial Analyst extension) on the winter home ranges of VHF-tracked juveniles. As a result of few juveniles encountered and very few locations collected, the available data did not permit meaningful analyses. Estimate First-year Survival (overall and by study area) - We treated each yearâ&#x20AC;&#x2122;s set of radio-tagged juveniles as an even-aged cohort to estimate first year survival based on the number of individuals determined to still be alive (based on systematic aerial searches through the year) at one year old. Determine Extent of Philopatry to Natal Areas â&#x20AC;&#x201C; This description was based on the proportion of surviving 1-year old radio-tagged herons that returned to and established activity ranges that included their natal site. Seasonal Movements and Survival of Adults

Describe post-breeding dispersal and measure summer and winter ranges - We obtained supplemental funding from the U. S. Fish and Wildlife Service to capture 5 adult Great White Herons in the lower Florida Keys (Florida Keys National Wildlife Refuges) and fit them with 22-g (<3% of body weight) solar-powered satellite transmitters with GPS-recording capability (5-year life, Microwave Telemetry, Inc., Columbia, MD). The adult herons were captured on nests with a circular noose carpet, a light wire mesh with nylon monofilament slipknow nooses placed on the nest after flushing the attending heron and replacing the clutch with dummy eggs. The natural eggs were stored temporarily in an insulated cooler to maintain their temperature during the trapping and tagging process. The transmitters were attached with a Teflon-ribbon harness of a proven design and standard measurements were taken. We also collected a small blood sample (<0.2 cc) for subsequent sex determination. The GPS component of the transmitter unit was programmed to determine and store, for subsequent retrieval via satellite, 6 to 8 locations per 24 hours with an accuracy of 10 to 15 meters. Available funding will pay for at least 2 years of data processing and delivery by CLS America, Inc. (formerly Service Argos, Inc.). Estimate annual adult survival - We estimated apparent survival from this small sample during the 2009/2010 nesting season and the post-breeding period.

RESULTS Foraging Energetics of Breeding Adults Five adult Great White Herons were captured at their nests within the GWHNWR from December 2009 to January 2010 and fitted with GPS satellite transmitters. The nests were on 4 islands within 20.7 km of each other (2 on Little Pine Key Mangrove; and 1 each on Hardup

Key, North Horseshoe Mangrove, and Upper Harbor Key, Fig. 1). All but 1 bird (#36312) were females (Table 1). All of the active nests at which the 5 herons were captured were abandoned soon after the adults (1 per nest) were trapped and radio tagged. After capture, we did not return to the nests for 3 days to 1 week to minimize additional disturbance. Upon additional visits, all eggs were completely in tact within the abandon nests for up to 1 month after capture. Heron #41246 moved directly to Annette Key (5.3 km) the day after being tagged and remained there for the duration of the study (Fig. 2). Another heron, #68231, moved south from Hardup Key to Bahia Honda State Park (9.76km), where it spent most of the remainder of the study except for several northward forays of 1 to 5 days before returning to Bahia Honda State Park (Fig. 3). The other 3 Great White Herons apparently re-nested soon after being tagged. Heron #36312, the only male, moved to a small unnamed island 1.1 km west of its capture location (and original nest) and, within a week, began building a new nest. He made repeated trips to and from this island and roosted there at night until 16 April 2010. On 25 April 2010, we received the last fix for this bird on the northeast shore of Mayo Key, 7.4 km from his re-nest site (Fig. 4). The other 2 tagged female herons re-nested within 0.02 km of their original nest site on the same island. Heron #93445 made first visits to the new nesting site on Little Pine Key Mangrove within 24 days of capture and probably began incubating around 9 January 2010 (Fig. 5). Heron #68229 visited its new nest area on Upper Harbor Key within 8 days of capture (Fig. 6). Determine the Spatial Relationships Between Foraging and Nesting Sites- We tracked the 3 adult herons that re-nested from their nest areas to foraging locations (1 male, 2 females)

and monitored the foraging movements of the 2 adult females that did not re-nest. We tracked all 5 birds for an average of 149 days each, obtaining an average of 4.5 daily locations per bird (Table 2 and Figs. 2-7). The GPS data revealed that each individual Great White Heron repeatedly returned to and remained within very specific foraging locations. As a result, distances between consecutive locations were often 0 meters. We calculated each heronâ&#x20AC;&#x2122;s cumulative movements since tagging with and without the 0-meter distances (Table 2). The mean number of presumed locations was 671 per bird (range: 432 to 925). Mean travel distance between locations with 0-meter moves included was 0.69 km (range 0.19 to 1.34 km). The mean maximum distance traveled was 9.09 km (range 3.6 to 13.30). With the 0-meter moves (4 to 16% of the 5 birdsâ&#x20AC;&#x2122; total locations), the mean distance between locations was 0.82 km (range: 0.21 to 1.56 km, Table 2). For this analysis, we used only those locations on water and within the range of dates for which the 3 re-nesting herons remained in their nest areas (Table 2). These birds were within the nest area an average of 118 days and produced an average of 141 locations. The male and one female had very similar mean travel distances between locations, 1.66 and 1.67 km, respectively (Table 2). The other nesting female however had a much larger mean travel distance at 10.10 km. Thus, distances between successive locations of the 3 nesting Great White Herons were different (ANOVA, F = 398.25, p < 0.001). We also examined foraging distances from nests using the far larger location samples derived the boat-survey observations of foraging Great White Herons (Figs. 8 and 9, Table 3). Unlike the satellite/GPS locations, these data were produced in both the lower Keys and Florida Bay study areas. In this case, we considered the numbers of foraging herons within 3 radii (4, 8, and 12 km) of known nesting colonies ranging in size from 3 to 88 Great White Heron nests.

The mean distance between foraging locations and nearest nesting colonies in Florida Bay was 3.65 kilometers. In GWHNWR, the mean distance was 7.13 kilometers. The number of birds differed within the 8 km radii from nesting colonies (ANOVA, F = 11.54, p = 0.008), showing more herons closer to the colonies in Florida Bay than GWHNWR (Table 3). Quantify Foraging Efficiency - We were able to collect reliable foraging-watch data for 38 Great White Herons, of which 26 (19 in Florida Bay and 7 in GWHNWR) were seen capturing prey. These successful feeding bouts are the basis of the data summarized here and in Table 4. Average observation time was 43 minutes per bird, during which the herons captured 1 to 7 fish as a result of 1 to 15 strikes. Overall, foraging efficiency appeared greater in GWHNWR with 0.159 strikes/minute versus 0.072 strikes/minute in Florida Bay (ANOVA, F = 6.51, p = 0.017); although not significantly different there were 0.689 catches/strike in GWHNWR versus 0.521 (ANOVA, F = 1.46, p = 0.239); and 0.094 catches/minute versus 0.036 catches/minute in Florida Bay (ANOVA, F = 6.49, p = 0.017). Furthermore, the size class (1-5+, where 5+ is the largest) of fish captured most frequently in GWHNWR was class 4, compared with class 1 in Florida Bay (Table 4). The 3,361 cumulative GPS locations for the 5 satellite-tracked Great White Herons allowed us to examine the temporal distribution of behaviors. We separated day (n = 2,787) from night (n = 574) locations, then over laid them on water and land habitats to determine the percentage of time spent foraging versus loafing/nesting during day and night. There was almost an equal distribution of time spent foraging or loafing/nesting during day and night hours (foraging: 42.52% day, 41.11% night; loafing: 57.48 day%, 58.89% night; two-tailed Fisherâ&#x20AC;&#x2122;s exact test p = 0.547 ). Monitor Nests Success and Productivity; Relate to Foraging Efficiency.- In 2008, 8

colonies in Great White Heron National Wildlife Refuge (GWHNWR, n = 137 nests, Fig. 9) and 5 in western Florida Bay (n = 102 nests, Fig. 8) were visited every 1 to 2 weeks to find and monitor active nests of Great White Herons (Table 5). Of the 239 nests found, we determined fates for 209 (87%). Undetermined outcomes resulted from our inability to assess nestling/fledgling survival with confidence (i.e., they may have fledged early, between our visits, and could not be detected in the area to confirm success). We completed nest monitoring at the end of March, when nearly all monitored nests had either fledged or failed. Of the 8 colonies in GWHNWR, Coon Key and Howe Key Mangrove had the most nests in both years (103 and 84, repectively, in 2008 and 2009), while each of the other colonies had <14 nests in both years, an average of 5.2 nests per colony (Table 5). Howe Key Mangrove had the highest nest success, 80.5%, among all colonies monitored in both study areas. In Florida Bay, there were fewer colonies (5) and nests (Table 5). Clive Key had the most nests, 127 out of 248 (51%), and Buoy Key had the highest nest success at 66.7%. In 2009, all colonies in GWHNWR (n = 112 nests) and Florida Bay (n = 146) were monitored except for 1 colony in GWHNWR (Happy Jack, Table 5). Of the 258 nest structures found, 215 were active (i.e., contained eggs or young) and were subsequently monitored until fate could be determined. In GWHNWR, fates were determined for 76 of the 112 nests. Overall 75% of the monitored nests with known fates in GWHNWR were successful, having fledged at least one young. In western Florida Bay, 2 keys had fewer than 10 nests while the other 3 had at least 20 nests in 2009 (Table 5). Nest fates were determined for 98 of the 146 nests found in Florida Bay, 47% of which were successful. Clive Key had the greatest number of nests in western Florida Bay (n = 87). However, of the 50 nests with known fates on Clive Key, only 32% fledged

young. This was the lowest success rate of all the keys on which we monitored Great White Heron nests, regardless of location. In our first season, 2008, the mean number of fledged young (MFY) per successful nest was 1.72 in GWHNWR and 1.51 in Florida Bay (Table 6). Nest success based on nests in which eggs or young were observed and for which fate was determined was higher, 75%, in GWHNWR versus 56.7% in Florida Bay (Fisherâ&#x20AC;&#x2122;s exact test p = 0.008, Table 5). In 2009, the mean number of fledged young per successful nest in the GWHNWR was 1.85 chicks, and 1.86 chicks in western Florida Bay, thus very similar across regions (Table 6). Nest success based on the number of known nests fates was 76.3% (GWHNWR) and 47.9% (Florida Bay, Table 5, Fisherâ&#x20AC;&#x2122;s exact test, p < 0.001). Is Foraging Habitat Limiting for Breeding Adults? Of the 3,361 GPS locations obtained from the 5 tagged Great White Herons, 1,421 were over water and, presumably, represented foraging locations. The area of water within the MCP created by the locations for all 5 herons was 390,902 square kilometer (Fig. 10). For the purpose of this analysis, we considered this the available foraging area for the tagged herons. There were 7 of the 11 habitat classes delineated within the available area. Continuous seagrass accounted for 60% of the available foraging area and 62% of the randomly-selected locations within the available area (Table 7). Moderate to dense continuous seagrass beds, was the habitat class selected most frequently by the foraging Great White Herons (92% of locations; Table 7). Foraging Great White Herons were found in only 3 other habitats, and then only minimally: patchy seagrass, hardbottom with seagrass, and bare substrate (Table 7). Of 1,202 observations from foraging survey routes, 740 were great white herons and 462 were great blue herons (Table 8). Feeding areas consisted of 5 major habitat categories. In

addition, secondary categories were described by the combination of two categories (grass, mangrove, mud, rock, sand). Both Great White and Great Blue Herons were most frequently observed in grasses, consistent with the analysis of foraging locations for the 5 Great White Herons tracked by satellite (Tables 7 and 8). We categorized water depth based on the height of the water on the leg of the heron (in tenths of leg length). For the subset of herons for which we were able to confirm water depth, most were in depths of 0.2 to 0.6 leg lengths (Table 8). There was no significant difference between water depths for foraging Great Blue and Great White Herons (paired t-test, t = 1.81, p = 0.5). Map and Measure Feeding Territories (Defended Foraging Areas) - We gathered GPS foraging data on 5 herons tracked by satellite within the GWHNWR in 2010. These locations were mapped to create minimum convex polygons (MCP) of activity area as well as kernel home ranges (Figs. 11 to 16). There is apparent overlap in MCP and core areas of herons #68229 and #93445 (Fig. 11). The mean MCP area for the 5 Great White Herons with GPS satellite transmitters was 51.3 square kilometers (range: 4.91 to 96.30 square kilometers, Table 10). The largest and smallest activity ranges were from non breeding birds. The only male (presumably nesting) had the second smallest home range, 39.78 square kilometers. Kernel activity ranges from the 5 satellite tagged birds were calculated from an average of 672 locations per bird (range 433 to 926, Table 9). Kernel activity ranges for 90% of GPS locations ranged from 0.32 to 55.66 square kilometers (mean: 17.89 square kilometers, Table 10). At 80%, the mean activity range was 10.39 square kilometers (range: 0.21 to 33.49) and at 70%, the mean area was 6.79 square kilometers (range 0.14 to 21.68 square kilometers, Table

10). In addition to the GPS data, we used foraging-survey location data for visually-detected Great White Herons in relation to nesting colonies (Figs. 8-9). We established 4 foraging survey routes throughout GWHNWR and 1 route in western Florida Bay (Table 11). Each route was surveyed 1 to 3 times per season. Route replicates were limited due to weather, tides, and safety concerns. Both Great White Herons and Great Blue Herons were noted on the survey routes. Of the 1,202 herons counted during the boat surveys, 61.6% were white (Table 11). In the GWHNWR, the most herons were seen on the East Central route and the least on the West Central route (Table 11). The single route surveyed in Florida Bay produced more foraging Great White Herons than any route in GWHNWR study area, with 260 observations over 5 replicates (Table 11). Determine the Extent of Competitive and Aggressive Interactions Between Foraging Herons - Conspecific interactions were recorded during the timed foraging observations conducted in 2008. We gathered data on 38 foraging Great White Herons throughout the study area and noted 20 encounters between conspecifics (3 defensive and 17 aggressive, Table 4). For every foraging Great White Heron observed, there was an average of 1.37 other Great White Herons (up to 9) and 0.53 Great Blue Herons (up to 9) within10 to 300 meters (mean 123, Table 4). The most common conspecific interactions were defense of a foraging area, during which focal herons prevented other herons from landing within 10 to 150 meters, displacing the feeding herons and forcing them to fly to new locations. Quantify Degree of Habitat Saturation - From the foraging routes, we identified 539 locations of Great White Herons and Great Blue Herons feeding within the study area (Tables 4

and 11; Figs. 8 and 9). There were 375 locations with only 1 foraging heron, and 504 locations had fewer than 5 foraging herons. There were 35 locations that had 6 to 55 herons foraging in the vicinity. Two of the satellite-tracked adult herons, both females, had overlapping kernel activity ranges (#68229 and #93445) (Figs 11, 14, and 16). Heron #93445 had the largest activity range, which almost completely contained that of #68229 (Fig. 11). Only a fraction of #68229â&#x20AC;&#x2122;s 60 to 90% volume was outside of the 90% volume for #93445. The core area of the 10% volume for #68229 was within the 40-60% volume of #93445â&#x20AC;&#x2122;s activity range. Dispersal and Survival of Juveniles Describe Post-fledging Dispersal and Measure Winter Range - From January through March of 2008, we collected biometrics, blood, and feather samples from 26 GWHE nestlings (Table 12). Twenty-one nestlings (GWHNWR: n = 11; Florida Bay: n = 10) were fitted with VHF transmitters. In 2009, we handled 43 GWHE nestlings (Table 12). Twenty-one nestlings (GWHNWR: n = 9; Florida Bay: n = 12) were fitted with VHF transmitters. The remaining 22 nestling were measured and banded only. All chicks handled in both years were fitted with a USFWS band on the left leg just above the foot; and an alpha-numeric, darvic color band placed on the right tarsometatarsus. Birds banded in western Florida Bay (n = 26) received a blue band with 2 white characters stacked, and birds tagged in GWHNWR (n = 17) received a red band with white characters. Of the 21 nestlings radio tagged early in 2008, 11 (GWHNWR: n = 5; Florida Bay: n = 6) were found alive on April 9, 2008. All but one of these birds were near their natal colonies. Most notable was a young male, #166.423, from a nest on Horseshoe Key Mangrove NW in eastern GWHNWR, which had moved northeastward about 45 kilometers to central Florida Bay

(ENP). Fifteen of the 21 nestlings radio tagged in 2009 (GWHNWR n = 10, Florida Bay n = 5) were found alive from the air at the end of March 2009. Eleven of these 15 (GWHNWR n=5; Florida Bay n=6) were detected alive at the end of April 2009 and still within the combined Florida Bay–Lower Keys study area. Too few tagged Great White Herons survived or remained under surveillance long enough (see below) to allow us to estimate winter-range areas. Determine Site Fidelity to Winter Ranges – Only one radio-tagged immature Great White Heron, #166.423 tagged in early 2008, was tracked during either winter (i.e., 2008/2009 or 2009/2010). Last located in mid-Florida Bay on 7 May 2008, this young heron was found on the north shore of Bahia Honda Key on 10 February 2009. We did not locate this bird on the intervening flights and do not know when it took up winter residence on Bahia Honda, but it was consistently located thereafter within the same relatively small area (i.e., < 2 square kilometers) through 22 October 2009. This transmitter and some remains of the bird were recovered in the first week of January 2010. Estimate First-year Survival (Overall and by Study Area) – By the end of April 2009, we were able to detect only one of the 2008 cohort of radio-tagged juveniles, male #166.423. This immature heron was consistently found along the shore of Bahia Honda (just west of the western end of Seven Mile Bridge) during the spring of 2009. This is the same bird, described above, for which we detected the longest movement during the post-fledging period (within 2 months of fledging). Thus, our last detection of any VHF-tagged Great White Herons marked as nestlings in early 2008 and 2009 was on 22 October 2009. This was #166.423, referred to above.

Subsequent flights throughout the Florida Keys, Ten Thousand Islands, Everglades, and Big Cypress swamp through January 2010 did not produce any further detections. Determine Extent of Philopatry to Natal Areas â&#x20AC;&#x201C; For the first 1 to 2 months postfledging, few of the radio-tagged juvenile Great White Herons were detected beyond 5 kilometers from their natal key in either GWHNWR or Florida Bay. Too few radio tagged Great White Herons survived or remained under surveillance long enough to allow us to comment with certainty on natal philopatry beyond 2 months post-fledging. However, 3 of the relatively few (n = 12) tagged herons that we continued to find during their third and fourth months post-fledging were detected at 98, 130, and 210 kilometers from their nests (respectively, GWHNWR to northern Ten Thousand Islands, GWHNWR to northern Big Cypress Swamp, and Florida Bay to St. Johns Marsh). Seasonal movements and survival of adults This topic was dropped from the original proposal when FWC offered partial funding and was replaced to the extent that the objectives could be addressed with available funds from USFWS and the remaining time in the FWC agreement. Determine post-breeding dispersal; measure summer and winter activity ranges within 1 year â&#x20AC;&#x201C; Opportunities to estimate post-breeding dispersal from the nesting key were limited to the 3 satellite-tracked Great White Herons that attempted to re-nest. The 2 females, which both re-nested on the same island as their original attempt, had maximum post-breeding movements of 10.8 and 13.3 kilometers, respectively. In the latter case, female #93445 moved repeatedly between this outermost location and her nesting site even though nesting responsibilities probably had ceased. The longest move of the other female, #68229, consisted of a loop of short duration, returning to the vicinity of the nesting key. Thus, neither of these femalesâ&#x20AC;&#x2122; moves,

although relatively long compared to their flights during nesting activity, appear to have been a well-defined dispersal movement. The 1 male, tracked for only about half as long as either of the females, moved a distance of 7.4 kilometers to a specific location at which he remained for 6 days before his signal was lost, most likely due to death. Estimate adult survival â&#x20AC;&#x201C; Because we tracked only 5 adults for 5 to 6 months posttagging, we lack sufficient data for a valid survival estimate. One of the 5 adults, the only male in the sample, died 3 months after being tagged following a sudden move 7.4 kilometers from the island on which it had re-nested after abandoning its original nest following capture and tagging. Given the insufficient time for the second nest to have fledged young, this heron probably left its territory after either nest failure or being forced out by a competing male.

DISCUSSION Foraging Energetics of Breeding Adults Our results for foraging performance were based on: 1) an intensive location dataset from 5 adults tracked by satellite transmitters with on-board GPS capability, providing abundant data on fine spatial and temporal scales in GWHNWR; and 2) a large number (>3,000) direct visual observations in both GWHNWR and Florida Bay. Foraging efficiency appeared to be higher in GWHNWR than in Florida Bay by all 3 criteria: strikes per minute (by ~20 times), catches per strike (by 33%), and catches per minute (by 300%. In addition, the most frequent size class of fish captured was 4 in GWHNWR versus 1 in Florida Bay (on a scale of 1 to 5). This indicates a clear difference between the potential of the two areas to support fish-eating birds, especially during the breeding cycle.

In fact, nesting success in GWHNWR exceeded that of Florida Bay by clear margins in both years. Young fledged per successful nest differed little in one year and was similar in the other. However, young fledged per nesting attempt (i.e., taking failed nests into account) differed substantially between areas, at 44% higher in GWHNWR for both years combined. We are not sure how to interpret the fact that successful Florida Bay nests produced as many young as those in GWHNWR (i.e., number of young fledged per successful nest was similar between the areas). This suggests that whatever caused failures in the Florida Bay nests usually resulted in the loss of all eggs or young in each affected nest. Tentatively, this would make predation appear to be a more likely source of nest failure in Florida Bay than food stress, which probably would have resulted in depressed mean fledged young per successful nest. We did note the much higher prevalence of crows on and near nesting islands in Florida Bay. Crow depredation of unattended eggs was most likely the greatest proximate cause of disturbancerelated nest failures on Florida Bay during this study, whereas it was relatively rare in the GWHNWR study area. The relatively equal number of day and night locations during presumed foraging behavior (i.e, over water) is consistent with the anecdotal reports that this species forages with regard to tide rather than diurnal cycles. The same was true for presumed loafing and nesting behaviors (i.e., over land). This highlights the importance of water depth in foraging decisions and performance, an issue of growing concern in light of climate change. One of the most informative results derived from the spatially-precise GPS tracking was the high degree of site fidelity, on a very fine scale, exhibited by each bird. The core areas and the specific, repeatedly-used foraging microsites of the 5 tracked Great White Herons were remarkably well defined and heavily used. This fidelity helps to explain the high frequency of

agonistic encounters among foraging individuals and the high degree of aggression that often characterizes these interactions. Is Foraging Habitat Limiting for Breeding Adults? The average home range size for the 5 birds tracked by satellite in GWHNWR was 51 square kilometers during the combined breeding and post-breeding periods. This is relatively large given the available foraging substrate in the lower Florida Keys and, indeed, there was substantial overlap in the home ranges of these 5 adults (Fig. 11 for MCPs; and Figs.12-16 for individual range maps based on kernel densities). Nonetheless, based on the visual observations of foraging birds, a Great White Heron had an average of 1.37 other Great White Herons within 10 to 300 meters (it was 0.53 for Great Blue Herons). This reflects the relatively low abundance and population density for Great White Herons. For a subset of 539 visually-observed foraging locations sampled specifically to estimate proximity to conspecifics, 70% of observed Great White Herons had only 1 other heron in close proximity and 94% had <5. The spatial relationships of Great White Herons in the lower Florida Keys are brought into sharper light when these results are considered with reference to habitat selection. While 60% of the available area consisted of continuous seagrass beds, 92% of the heron GPS locations were in this habitat type. While hardbottom seagrass beds were not selected for relative to their availability, it appears the close spatial association of hardbottom beds may increase the attractiveness of continuous seagrass beds. This habitat analysis may be our most important result because it illuminates the importance not just of seagrass but of intact, expansive beds of this plant community to Great White Herons, in and out of the nesting season. The fact that isolated small patches or

discontinuous stands of seagrass do not attract herons suggests it is not the physical structure of this community that appeals to foraging Great White Herons but the more fundamentally important value of healthy, expansive seagrass beds for producing the fish on which this large bird depends. Dispersal and Survival of Juveniles In general, for all the radio-tagged Great White Herons (both the 2008 and 2009 cohorts, total n=42), detectability varied substantially depending on the marked birdâ&#x20AC;&#x2122;s position relative to vegetation. The signals of those under the mangrove canopy of islands usually could not be heard unless the observerâ&#x20AC;&#x2122;s boat or even aircraft was within 2-5 kilometers and, often not until within less than 2 or 3 kilometers. However, if a bird was on a tidal flat, we could detect its signal from the air at distances of 60 kilometers or more. Thus, we are confident that our aerial tracking methods over the duration of the study ensured a relatively high detection probability for any live birds remaining in south Florida through 1 (for the 2009 cohort) to 2 (for the 2008 birds) years post-fledging. In any case, studies of first-year survival in birds, and especially those with an interest in eventual recruitment to the breeding population, require very large samples and sufficient resources for very intensive tracking efforts. While the single bird we tracked into its second year was helpful in this regard, our data did not support valid estimates of winter home range and site fidelity, as we had hoped, because of the very low detectability of the tagged herons beyond 2 months post-fledging. Although we believe first-year survival is relatively low for Great White Herons, as it is for many bird species, detectability of our radio-tagged sample of 42 juvenile probably was poor within the geographic area that we could feasibly search. Under these circumstances, an estimate

of apparent first-year survival based on only 1 individual alive at 1 year old is of little value. Instead, it is worth considering the pattern of detections during the several months post-fledging. Natal philopatry appeared well defined during the 1 to 2 months post-fledging. Thereafter, however, there was a sudden loss of contact with nearly all of the tagged juveniles. Even the single male that we subsequently found on Bahia Honda, where he remained until his death 8 to 10 months later, went undetected for 5 months despite repeated, systematic aerial searches in south and central Florida. Most telling, however, were the 3 juvenile Great White Herons found during their third and fourth months post-fledging at 98, 130, and 210 kilometers north of their natal areas (and never again). Given this result, our unreasonably low estimate of apparent survival, this speciesâ&#x20AC;&#x2122; delayed sexual maturation, anecdotal evidence of wide-ranging Great White Herons observed throughout the southeastern United States, and the birdâ&#x20AC;&#x2122;s occurrence in the Caribbean, we believe first-year birds may temporarily disperse over a broad area before returning to the south Florida breeding range at 2 to 4 years of age. The VHF transmitters used in this study are expected to operate for 3 to 4 years. We are seeking limited funding to support at least one telemetry survey in south Florida during February (and March, if possible) 2011 to search for any surviving 2- and 3-year old Great White Herons that may be returning for the first time as potential breeding birds. Seasonal movements and survival of adults Funding for satellite/GPS tracking for 5 birds allowed us to investigate, at least tentatively, range sizes, foraging distances, post-breeding movements and range fidelity, and habitat use of adult Great White Herons. Trapping was successful within a reasonable time period and no adults were injured in the process. However, trapping at the nests of these 5

breeding birds resulted in abandonment (all during the egg stage) by both members of each pair. Three of the 5 re-nested, but 1, the only male, failed mid-stage and apparently died 9 days later (the carcass was not recovered and there was no suspected cause). The satellite/GPS dataset used for this report had an end date of 1 July 2010. However, as of 1 January 2011, all 4 satellite-tracked female Great White Herons were still providing movement data, and all 4 have continued to use mainly the same areas described here, an average of a year after being tagged. That is, there is little difference in location or extent of the home ranges during the breeding season and all other times of year. We expect that the 4 satellite/GPS units will continue to operate for another 3 to 4 years, providing a wealth of precise location data for this small but valuable sample of Great White Herons.

MANAGEMENT IMPLICATIONS Expansive seagrass beds are vitally important to Great White Herons in the lower Florida Keys. The concentrated distribution of the present heron population, centered around the largest remaining beds, suggests that this fragile habitat may be limiting. Protection of the quality and extent of the remaining large seagrass beds, and restoration and of expansion of the damaged remaining beds, should be high priorities for habitat management in the Florida Keys NWRs. Human disturbance on islands containing nesting colonies that include Great White Herons probably has direct impacts on nesting effort, success, and productivity. This applies to all colonially-nesting birds in Florida Keys and the rest of the state. Enforcement of existing regulations meant to control disturbance is essential. Where access is unlimited,

restrictions should be considered, at least seasonally, wherever Great White Heron nesting occurs. Sea-level rise resulting from climate change undoubtedly will affect all waterbirds on the Florida coast, and perhaps most severely in the Florida Keys, where effects are already apparent. Great White Herons will be particularly vulnerable because of their small and declining population, their use of low-lying islands for nesting, the limited extent of suitable foraging habitat, and their reliance on shallow flats during limited portions of the tide cycle for access to prey. Apparently it is difficult to predict the finely-scaled responses of the soft substrates of the foraging flats and mangrove forests to sea-level rise and, thus, to assess potential impacts on species such as Great White Herons.

LITERATURE CITED Cook, M. I., and E. M. Call. 2006. South Florida Wading Bird Report. Volume 12, October 2006. South Florida Water Management District, Everglades Division. West Palm Beach, Florida, USA. Florida Fish and Wildlife Conservation Commission. 2005. Floridaâ&#x20AC;&#x2122;s Wildlife Legacy Initiative. Floridaâ&#x20AC;&#x2122;s Comprehensive Wildlife Conservation Strategy. Tallahassee, Florida, USA. Hooge, P. N., and B. Eichenlaub. 1997. Animal movement extension to Arcview. version. 1.1. Alaska Biological Science Center, U.S. Geological Survey, Anchorage, Alaska, USA. Hunter, W. C., W. Golder, S. Melvin, and J. Wheeler. 2006. Southeast United States Regional Waterbird Conservation Plan. U.S. Fish and Wildlife Service, Atlanta, GA, USA. http://www.fws.gov/birds/waterbirds/SoutheastUS/seplanfinal906.pdf McGuire, H. L. 2001. Evaluating the taxonomic status of the Great White Heron using morphological, behavioral, and genetic evidence. Ph.D. dissertation, Louisiana State University, Baton Rouge, Louisiana, USA. Powell, G. V. N. 1983. Food availability and reproduction by Great White Herons: a food addition study. Colonial Waterbirds 6:139-147.

_____. 1987. Habitat use by wading birds in a subtropical estuary: implications of hydrography. Auk 104:740-749. _____. 1996. Great White Heron â&#x20AC;&#x201C; Species of Special Concern. Endangered biota of Florida, Volume 5, Birds. University of Florida Press, Gainesville, Florida, USA. _____, and A. H. Powell. 1987. Reproduction by Great White Herons in florida Bay as an indicator of habitat quality. Biological Conservation 36:101-113. _____, R. Bjork, J. Ogden, R. Paul, A. Powell, and W. Robertson, Jr. 1989. Population trends in some Florida Bay wading birds. Wilson Bulletin 101:436-457. _____, and R. Bjork. 1990. Studies of wading birds in Florida Bay: a biological assessment of the ecosystem. National Audubon Society comprehensive report to the E. O. Dunn Foundation, National Audubon Society, Tavernier, Florida, USA. Robblee, M. B., T. Barber, P. Carlson, M. Durako, J. Fourqurean, L. Muehlstein, D. Poerter, L. Yarbro, R. Zieman, and J. Zieman. 1991. Mass mortality of the tropical seagrass in Florida Bay. Marine Ecology Prog. Ser. 71:297-299. Stevenson, H. M., and B. H. Anderson. 1994. The birdlife of Florida. University of Florida, Gainesville, Florida, USA.

Table 1. Nest-site capture locations and re-nesting locations of 5 adult Great White Herons fitted with satellite/ GPS transmitters in the Florida Keys during the 2009/2010 breeding season. Capture date

Colony name/island

Nest latitude

Nest longitude

Sex

Satellite ID#

Color band code

12/3/2009

Little Pine Key Mangrove

24.75516

-81.34174

Female

93445

24.75502

1/19/2010

Upper Harbor Key

24.81269

-81.44202

Female

68229

24.81254

1/22/2010

Little Pine Key Mangrove

24.75549

-81.34112

Female

41246

1/24/2010

North Horseshoe Mangrove Key

24.78199

-81.29332

Male

36312

1/29/2010

Hardup Key

24.75734

-81.24702

Female

68231

New nest latitude

24.77791 na

New nest longitude

Nest status

Date

-81.34183

2 chicks 5-6 weeks old

3/19/2010

-81.44204

3 eggs

3/19/2010

2 chicks 3-4 weeks old

3/19/2010

-81.30372 na

Table 2. Distances 5 Great White Herons, tracked by satellite/GPS transmitters, traveled from nests sites (top table) and cumulatively (bottom table) in the Florida Keys in 2010. Distances include the both the breeding and post-breeding period. Distance from nest site to foraging locations (km)

# Locations PTT

Sex

36312

Male

68229

Female

93445

Female

# Track days

Total

By day

Mean

Variance

Min

Max

132

0.57

1.66

0.80

0.89

0.05

5.06

152

116

1.31

1.67

1.99

1.41

0.07

10.74

128

175

0.73

10.10

20.22

4.50

0.04

13.28

Mean

118.33

141.00

0.87

4.48

0.05

9.69

39.40

30.51

0.39

4.87

0.02

4.21

Dates 2/1/104/16/10 1/28/106/28/10 12/30/09 -5/6/10

# Locations PTT

Sex

36312

Male

68229

Female

93445

Female

41246

Female

68231

Female

Cumulative distance since tagged (km)

Distance without 0 (km)

# Track days

Total

By day

Mean

Variance

Min

Max

# 0s

Mean

Variance

432

4.75

0.73

1.23

1.11

0.00

7.40

107

4.04

0.97

1.40

1.18

164

818

4.99

0.68

1.53

1.24

0.00

10.77

117

6.99

0.79

1.70

1.30

184

925

5.03

1.34

10.33

3.21

0.00

13.30

127

7.28

1.56

11.65

3.41

156

542

3.47

0.19

0.06

0.25

0.00

3.60

15.49

0.21

0.06

0.25

152

639

4.20

0.49

2.26

1.50

0.00

11.68

8.30

0.55

2.53

1.59

Mean

149.40

671.20

4.49

0.69

9.09

92.60

8.42

0.82

31.21

179.39

0.59

0.38

3.64

33.31

3.81

0.45

Dates 1/25/104/25/10 1/19/107/1/10 12/30/09 - 7/1/10 1/22/106/26/10 1/29/106/30/10

Table 3. Number of Great White Herons and Great Blue Herons visually observed within 4-, 8-, and 12-km radii of nest colonies within GWHNWR and Florida Bay in 2008 and 2009.

Colony Name Great White Heron National Wildlife Refuge Marvin Key Friend Key Happy Jack Horseshoe Key Mangrove N Horseshoe Key Mangrove NW Coon Key Howe Key Mangrove Green Heron Mangrove Number of herons per region Florida Bay Jimmies North Pollock Key Buoy Key Clive Key Murray Key Number of herons per region Total herons within all radii

# nests

# of herons within radius size 4 km 8 km 12 km

6 7 1 9 16 64 82 3

10 9 16 45 45 19 151 35 285

29 75 60 86 89 126 336 147 615

63 114 115 117 137 207 373 386 693

14 2 46 88 45

0 0 72 173 266 338 623

0 0 238 349 420 508 1123

0 0 410 508 508 508 1201

Table 4. Foraging efficiency and aggressive encounters of Great White Herons observed in Florida Bay and GWHNWR in 2008.

Region FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay FL Bay GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR

Observation (min) 53 60 52 57 30 48 6 46 60 60 53 60 60 14 70 30 30 59 47 40 24 15 50 60 60 30 30 50 15 56 51 7 24 47

Strikes Total Catch 3 2 8 6 6 2 4 2 1 1 3 1 0 0 4 3 0 0 6 5 4 3 0 0 5 3 0 0 8 5 5 0 0 0 2 0 2 0 2 1 0 0 0 0 1 0 1 1 4 1 1 1 0 0 1 1 2 0 7 7 15 7 3 2 0 0 2 2

1 0 4 0 0 0 0 0 3 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 1 1 0 0

# of Prey caught by size category 2 3 4 5 5+ 0 1 1 0 0 1 1 0 0 0 1 0 0 1 0 0 0 0 1 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 2 0 0 3 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 2 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 2 2 1 0 5 0 0 1 0 0 0 0 0 0 0 0 0 2 0 0 0 0

Prey family Batrachoididae(1)/Unk(1) Sygnathidae(5)/Unk(1) Batrachoididae(1)/Unk(1) Mugilidae(1)/Sygnathidae(1) Belonidae Mugilidae Unk(3) Belonidae(5) Batrachoididae(3) Sygnathidae(1)/Unk(2) Batrachoididae(1)/Sygnathidae(1)/Gastropod(3)

Sygnathidae(1)

Ictaluridae Unk Unk Unk Sygnathidae(6)/Batrachoididae(1) Monacanthidae(2)/Sygnathidae(3)/Unk(2) Unk(2) Sygnathidae(1)/Unk(1)

# 0 0 2 2 3 2 1 1 1 4 1 0 3 1 1 2 0 7 2 1 1 1 1 1 0 1 0 5 0 1 2 1 1 1

Flight Distance (m) 0 0 >1000 20 400 >1000 150 >1000 >1000 210 300 0 >1000 >1000 100 20 0 340 >1000 100 200 >1000 >300 10 0 10 0 210 0 10 20 >1000 80 20

GWHNWR GWHNWR GWHNWR GWHNWR

40 32 50 60

0 0 0 4

0 0 0 3

0 0 0 0

0 0 0 2

0 0 0 1

0 0 0 0

Monacanthidae(2)/Unk(1)

2 0 0 2

300 0 0 500

Table 4. continued.

Time (min) 53 60 52 57 30 48 6 46 60 60 53 60 60 14 70 30 30 59 47 40 24 15 50 60 60 30 30 50 15

Encounter Aggressive Defensive 0 0 0 0 0 0 0 0 1 0 0 2 2 0 0 0 0 0 1 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 2 1 1 0 2 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0

# of Conspecifics GWHE GBHE 0 0 0 0 0 0 0 0 0 1 2 0 2 0 1 1 0 0 0 1 1 0 1 0 0 0 0 0 2 0 0 0 0 0 9 9 9 2 4 0 0 0 4 0 0 0 2 0 3 0 0 0 0 0 1 2 5 3

Meters between birds

Comments

150 150 200 50

Flew aggressively and pushed off GBHE 1 GWHE and 2 brown pelicans chassed, dropped fish, flushed by GWHE Prevented 2 GWHE from landing, chased a third 150m before settling

150 150 300

Prevented GBHE from landing Prevented GWHE from landing and chased off to the NE Displaced a foraging GWHE upon landing Caught and rejected a class 4 filefish (Tetraodontidae) Hunting active prey Flew away when others returned

10 10 100 200 250 200

50 50

Chased off a GWHE that got too close Chased off a GREG and a GWHE Flew off Displaced by another GWHE Adult, appeared to be hunting fast prey (i.e. mullet), flew to mainland Defended fish from brown pelicans, fish then stolen by a bald eagle

GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR

56 51 7 24 47 40 32 50 60 Total

0 1 0 0 0 2 0 0 1 17

0 0 0 0 0 0 0 0 0 3

0 1 0 1 0 2 1 0 1 Mean=1.37

0 0 0 0 0 1 0 0 0 0.53

Chased off 1 GWHE Flew to roost, 1 GWHE fly-by without any response from focal animal 150 10 150 123.16

Chased off GWHE and GBHE, spent more time defending foraging area 2nd bird Juvenile,no response when landing nearby

Table 5. Nest success of Great White Herons in Florida Bay and GWHNWR in the 2007/2008 and 2008/2009. Great White Heron National Wildlife Refuge

West Florida Bay, Everglades National Park

Colony Name 2007/2008 Coon Key Friend Key Green Heron Mangrove Happy Jack Horseshoe Key Mangrove N Horseshoe Key MangroveNW Howe Key Mangrove Marvin Key Region Total

Nest Total 54 5 2 2 10 7 49 8 137

Successful 39 2 1 1 2 4 33 2 84

Failed 8 3 0 0 4 2 8 3 28

Unk. 5 0 1 1 4 1 8 3 23

Colony Name 2008/2009 Coon Key Friend Key Green Heron Mangrove Horseshoe Key Mangrove N Horseshoe Key MangroveNW Howe Key Mangrove Marvin Key Region Total

Nest Total 26 3 3 6 14 58 2 112

Successful 11 2 2 2 8 33 0 58

Failed 6 0 0 1 2 8 1 18

Unk. 4 1 1 0 0 14 0 20

Colony Name Buoy Key Clive Key Jimmies North Murray Key Pollocks

Region Total Never Initiated 5 0 0 3 4 3 1 16

Colony Name Buoy Key Clive Key Jimmies North Murray Key Pollocks

Region Total

Nest Total 26 40 8 27 1

Successful 16 22 4 13 0

Failed 8 16 4 13 1

Unk. 2 2 0 1 0

102

Nest Total 25 87 9 24 1

Successful 12 16 3 14 1

Failed 10 34 3 5 0

Unk. 0 18 1 2 0

Never Initiated 3 19 2 3 0

146

Table 6. Mean fledged young (MFY) and standard deviation (SD) of Great White Herons per nest for each colony and each region during the 2007/2008 and 2008/2009 nesting seasons. See Table 5 for nest sample sizes per colony and region. Great White Heron National Wildlife Refuge MFY per Successful Nest (SD) Colony Name 2007/2008 Coon Key 1.74 (0.55) Friend Key 2.00 (0) Green Heron Mangrove 2.00 (0) Happy Jack 2.00 (0) Horseshoe Key Mangrove N 1.00 (0) Horseshoe Key Mangrove NW 2.00 (0.82) Howe Key Mangrove 1.63 (0.56) Marvin Key 2.00 (0)

MFY per Nest (SD) 1.53 (0.78) 0.80 (1.10) 2.00 (0) 2.00 (0) 0.33 (0.52) 1.33 (1.21) 1.29 (0.84) 0.80 (1.10)

Region Great White Heron National Wildlife Refuge W. Florida Bay, Everglades National Park

MFY per Successful Nest (SD) 1.72 (0.55) 1.51 (0.64)

MFY per Nest (SD) 1.31 (0.88) 0.85 (0.89)

Colony Name 2008/2009 Coon Key Friend Key Green Heron Mangrove Horseshoe Key Mangrove N Horseshoe Key Mangrove NW Howe Key Mangrove Marvin Key

MFY per Successful Nest (SD) 1.55 (0.52) 2.50 (0.71) 2.00 (1.41) 2.00 (0) 1.75 (0.71) 1.30 (0.47) N/A

MFY per Nest (SD) 0.65 (0.85) 1.67 (1.53) 1.33 (1.53) 0.67 (1.04) 1.00 (1.04) 0.74 (0.74) 0 (0)

Region Great White Heron National Wildlife Refuge W. Florida Bay, Everglades National Park

MFY per Successful Nest (SD) 1.50 (0.60) 1.50 (0.55)

MFY per Nest (SD) 0.77 (0.87) 0.47 (0.76)

West Florida Bay, Everglades National Park MFY per Successful MFY per Nest (SD) Nest (SD) Colony Name Buoy Key 1.5 (0.52) 1.00 (0.83) Clive Key 1.27 (0.46) 0.76 (0.71) Jimmies North 1.75 (0.96) 0.88 (1.13) Murray Key 1.90 (0.83) 0.88 (1.12) Pollock Keys 0 (0) 0 (0)

Mean Clutch Size (SD) 2.73 (1.00) n = 67 2.53 (1.13) n = 60

Colony Name Buoy Key Clive Key Jimmies North Murray Key Pollock Keys

Mean Clutch Size (SD) 2.95 (0.67) n = 95 2.85 (0.54) n = 108

MFY per Successful Nest (SD) 1.50 (0.52) 1.31 (0.48) 2.00 (0) 1.50 (0.52) 3 (N/A)

MFY per Nest (SD) 0.72 (0.84) 0.24 (0.55) 0.67 (1) 0.88 (0.85) 3 (N/A)

Table 7. Foraging habitats of Great White Herons tracked by satellite in the Florida Keys in 2010 compared with an equal number of random locations and the proportions of these habitats within the available area.

Habitats within total Great White Heron MCP Continuous Seagrass Patchy (Discontinuous) Seagrass Hardbottom with Seagrass Bare Substrate Hardbottom Inland Water Uninterpretable Land Total

Available Area sq km % 209226.14 0.605 37335.66 0.108 95158.59 0.275 1364.61 0.004 239.54 0.001 483.43 0.001 2192.91 0.006 44901.01 390901.89 Foraging/water locations Roosting/nesting/ land locations Total heron locations

Great White Heron # % 1307 0.920 82 0.058 25 0.018 7 0.005 0 0.000 0 0.000 0 0.000

Random # % 875 0.616 140 0.099 389 0.274 6 0.004 1 0.001 4 0.003 6 0.004

1421

1940

3361

Table 8. Habitat classifications and water depths for 1,202 foraging sites of Great White Herons and Great Blue Herons observed along survey routes in Florida Bay and GWHNWR in 2008 and 2009.

Total

Great White Heron Number Percentage 267 0.361 132 0.178 86 0.116 55 0.074 47 0.064 39 0.053 27 0.036 20 0.027 10 0.014 9 0.012 8 0.011 3 0.004 37 0.050 740

Great Blue Heron Number Percentage 201 0.435 125 0.271 13 0.028 28 0.061 42 0.091 22 0.048 2 0.004 0 0.000 0 0.000 4 0.009 2 0.004 0 0.000 23 0.050 462

Total 468 257 99 83 89 61 29 20 10 13 10 3 60 1202

Depth (10th of leg length) 0 1 2 3 4 5 6 7 8 9 10 Unknown Total

Great White Heron Number Percentage 7 0.012 29 0.049 95 0.160 111 0.187 84 0.142 82 0.138 88 0.148 23 0.039 47 0.079 13 0.022 14 0.024 147 740

Great Blue Heron Number Percentage 4 0.009 10 0.024 67 0.158 95 0.224 66 0.155 72 0.169 56 0.132 8 0.019 19 0.045 26 0.061 2 0.005 37 462

Total 11 39 162 206 150 154 144 31 66 39 16 184 1202

Substrate Grass Mud/Grass Mangrove Rock/Grass Grass/Sand Mud Rock Mangrove/Grass Rock/Mangrove Sand Sand/Mangrove Rock/Sand Unknown

Table 9. Activity-range areas (kernel densities by proportion of locations) based on satellite/GPS-derived locations of 5 Great White Herons in the Florida Keys during 2010. PTT# 36312 36312 36312 36312 36312 36312 36312 36312 36312

Volume 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10

Density 1.83E-08 6.27E-08 1.04E-07 1.43E-07 1.58E-07 2.05E-07 2.43E-07 3.02E-07 3.73E-07

H 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36

# Locations 433 433 433 433 433 433 433 433 433

Area (sq km) 7.37 4.71 3.47 2.46 2.02 1.25 0.79 0.44 0.17

41246 41246 41246 41246 41246 41246 41246 41246 41246

0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10

5.80E-07 1.48E-06 2.58E-06 3.19E-06 4.14E-06 5.12E-06 5.66E-06 6.31E-06 6.66E-06

0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35

543 543 543 543 543 543 543 543 543

0.32 0.21 0.14 0.11 0.08 0.05 0.03 0.01 0.01

68229 68229 68229 68229 68229 68229 68229 68229 68229

0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10

1.96E-08 3.71E-08 7.00E-08 1.07E-07 1.37E-07 2.23E-07 3.25E-07 4.10E-07 4.42E-07

0.33 0.33 0.33 0.33 0.33 0.33 0.33 0.33 0.33

819 819 819 819 819 819 819 819 819

9.45 5.58 3.55 2.40 1.75 1.06 0.57 0.27 0.17

68231 68231 68231 68231 68231 68231 68231 68231 68231

0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10

5.40E-09 2.13E-08 5.24E-08 8.88E-08 1.15E-07 1.66E-07 1.92E-07 2.45E-07 2.59E-07

0.34 0.34 0.34 0.34 0.34 0.34 0.34 0.34 0.34

640 640 640 640 640 640 640 640 640

16.66 7.97 5.12 3.43 2.66 1.55 1.10 0.39 0.23

93445 93445 93445 93445 93445 93445 93445 93445 93445

0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10

3.00E-09 7.50E-09 1.42E-08 1.81E-08 2.54E-08 3.00E-08 3.66E-08 5.13E-08 6.28E-08

0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32

926 926 926 926 926 926 926 926 926

55.66 33.49 21.68 17.30 11.30 8.25 5.77 2.76 0.91

Table 10. Activity-range areas based on kernel densities (by proportion of locations) and minimum convex polygon (MCP) areas based on satellite/GPS-derived locations for 5 Great White Herons in the Florida Keys in 2010. Area (sq km) of activity ranges by proportion of locations

MCP

PTT# 36312 41246 68229 68231 93445 Mean

0.90 7.37 0.32 9.45 16.66 55.66 17.89

0.80 4.71 0.21 5.58 7.97 33.49 10.39

0.70 3.47 0.14 3.55 5.12 21.68 6.79

0.60 2.46 0.11 2.40 3.43 17.30 5.14

0.50 2.02 0.08 1.75 2.66 11.30 3.56

0.40 1.25 0.05 1.06 1.55 8.25 2.43

0.30 0.79 0.03 0.57 1.10 5.77 1.65

0.20 0.44 0.01 0.27 0.39 2.76 0.77

0.10 0.17 0.01 0.17 0.23 0.91 0.30

Area (sq km) 39.78 4.91 47.19 96.30 68.33 47.04

Perimeter (km) 27.32 12.54 30.50 39.60 34.14 27.49

SD Min Max

21.90 0.32 55.66

13.22 0.21 33.49

8.52 0.14 21.68

6.91 0.11 17.30

4.43 0.08 11.30

3.30 0.05 8.25

2.34 0.03 5.77

1.12 0.01 2.76

0.35 0.01 0.91

37.66 4.91 96.30

11.24 12.54 39.60

Table 11. Numbers of Great White Herons and Great Blue Herons observed during foraging route surveys in 2008 and 2009 in Florida Bay and GWHNWR.

Route name East GWHNWR East Central GWHNWR West Central GWHNWR West GWHNWR West Florida Bay

Date 1/17/08

Survey 1 GBHE GWHE 1 15

Total 16

Date 3/12/08

Survey 2 GBHE GWHE 15 30

Total 45

Date 2/7/09

Survey 3 GBHE GWHE 9 43

Date

1/5/09

3/13/09

162

1/1/08

1/18/08

1/19/08

1/18/08

3/13/08

2/21/09

1/10/08

2/14/08

2/28/09

3/21/08

119

1/30/09

2/12/09

158

Total

GBHE 25

Total GWHE 88

All 113

209

295

118

204

248 462

260 740

508 1202

Date

3/19/09

3/17/09

Survey 5 GBHE GWHE

15 Total

Survey 4 GBHE GWHE

Total 52

Total

Table 12. Location, VHF frequency, and leg band IDs of Great White Heron nestlings marked at nests in Florida Bay and GWHNWR in 2008 and 2009. Color band Region

Colony Name

Date

Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR

Buoy Key Buoy Key Buoy Key Buoy Key Buoy Key Clive Key Jimmies Key Murray Key Murray Key Murray Key Murray Key Coon Key Coon Key Coon Key Coon Key Friend Key Friend Key Green Heron Mangrove Horseshoe Key Mangrove NW Howe Key Mangrove Howe Key Mangrove Howe Key Mangrove Howe Key Mangrove Howe Key Mangrove Howe Key Mangrove Howe Key Mangrove

1/22/2008 1/22/2008 1/22/2008 1/22/2008 1/22/2008 2/7/2008 2/23/2008 2/23/2008 2/23/2008 2/23/2008 3/20/2008 1/9/2008 1/9/2008 1/9/2008 1/21/2008 2/15/2008 2/15/2008 2/15/2008 1/20/2008 1/20/2008 1/20/2008 1/20/2008 2/3/2008 2/3/2008 2/3/2008 3/14/2008

USFWS Band 0928-04460 0928-04461 0928-04463 0928-04462 0928-04464 0928-04468 0928-04472 0928-04473 0928-04474 0928-04475 0928-04477 0928-04452 0928-04453 0928-04454 0928-04459 0928-04470 0928-04471 0928-04469 0928-04458 0928-04457 0928-04455 0928-04456 0928-04465 0928-04466 0928-04467 0928-04476

Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay Florida Bay GWHNWR GWHNWR GWHNWR

Buoy Key Buoy Key Buoy Key Jimmies Key North Murray Key, Northeast Murray Key, Northeast Murray Key, Northeast Murray Key, Northeast Murray Key, Northeast Murray Key, Northeast Murray Key, Northeast Murray Key, Northeast Murray Key, Southwest Murray Key, Southwest Murray Key, Southwest Pollock Key Main Pollock Key Main Coon Key Coon Key Friend Key

2/9/2009 2/9/2009 3/11/2009 2/25/2009 1/28/2009 1/29/2009 1/29/2009 2/24/2009 2/24/2009 3/11/2009 3/11/2009 3/25/2009 1/12/2009 1/12/2009 2/23/2009 2/25/2009 2/25/2009 3/17/2009 3/17/2009 2/2/2009

0928-04499 0928-04500 0928-08414 0928-08406 0928-04484 0928-04485 0928-04486 0928-08404 0928-08405 0928-08415 0928-08416 0928-08419 0928-04478 0928-04479 0928-08403 0928-08407 0928-08408 0928-08417 0928-08418 0928-04492

Sex

Color

Code

Male Female Male Unknown Female Male Male Male Female Male Unknown Female Unknown Female Male Unknown Female Male Male Male Unknown Male Male Male Unknown Female

N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A

VHF Frequency 166.662 166.558 166.648 none 166.469 166.632 166.483 166.393 166.707 166.587 166.573 166.528 none 166.618 166.377 none 166.543 166.678 166.423 166.499 none 166.408 166.513 166.348 none 166.453

Male Female Male Male Female Male Female Female Male Female Female Male Male Female Female Male Male Male unknown Female

blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue red red red

9 over 5 9 over 7 U over 8 9 over 6 8 over 5 8 over 7 8 over 8 U over 6 U over 5 X over 5 X over 6 Y over 8 9 over 8 8 over 6 U over 7 X over 7 X over 8 M over 4 N over 1 9 over 2

167.164 none 166.939 167.001 167.213 none 166.364 166.833 none none 166.894 166.925 166.603 166.692 166.955 166.908 none 166.880 none none

GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR GWHNWR

Friend Key Friend Key Friend Key Friend Key Green Heron Mangrove Horseshoe Key Mangrove N Horseshoe Key Mangrove N Horseshoe Key Mangrove NW Horseshoe Key Mangrove NW Horseshoe Key Mangrove NW Horseshoe Key Mangrove NW Horseshoe Key Mangrove NW Horseshoe Key Mangrove NW Horseshoe Key Mangrove NW Horseshoe Key Mangrove NW Howe Key Mangrove Howe Key Mangrove Howe Key Mangrove Howe Key Mangrove Howe Key Mangrove Howe Key Mangrove Howe Key Mangrove

2/2/2009 2/3/2009 2/3/2009 2/16/2009 3/3/2009 2/27/2009 2/27/2009 1/14/2009 1/14/2009 1/14/2009 1/19/2009 2/2/2009 2/2/2009 2/2/2009 2/16/2009 2/4/2009 2/4/2009 2/4/2009 2/18/2009 2/18/2009 3/3/2009 3/3/2009

0928-04493 0928-04494 0928-04495 0928-04491 0928-08413 0928-08409 0928-08410 0928-04480 0928-04481 0928-04482 0928-04483 0928-04488 0928-04489 0928-04487 0928-04490 0928-04496 0928-04497 0928-04498 0928-08401 0928-08402 0928-08411 0928-08412

Male Male Female Male Female Female Male Male Female Male Female Male Male Male Female Male Female Female Male Female Male Female

red red red red red red red red red red red red red red red red red red red red red red

9 over 3 Y over 1 Y over 2 9 over 1 A over 1 U over 3 U over 4 8 over 2 8 over 1 8 over 3 9 over 4 X over 2 X over 1 X over 3 X over 4 Y over 3 Y over 4 8 over 4 U over 1 U over 2 M over 3 M over 2

none 166.747 none 167.09 none none none none none 166.439 166.757 none 166.852 none 167.137 167.183 none none none none 166.838 none

Figure 1. Capture locations (green) and re-nest locations (pink) of 5 Great White Herons tagged with satellite/GPS transmitters in the Florida Keys, 2010.

Figure 2. Capture location (yellow dot on Little Pine Key Mangrove) and subsequent satellite/GPS locations and movement pathways for Great White Heron #41246 in the GWHNWR, from capture date to 1 July 2010.

Figure 3. Capture location (yellow dot on Hardup Key) and subsequent satellite/GPS locations and movement pathways for Great White Heron #68231 in the GWHNWR, from capture date to 1 July 2010.

Figure 4. Capture location (yellow dot obscured by movement locations on Horseshoe Keys) and subsequent satellite/GPS locations and movement pathways for Great White Heron #36312 in the GWHNWR from capture date to date of last report on 25 April, 2010.

Figure 5. Capture location (yellow dot obscured by movement locations on Little Pine Key Mangrove) and subsequent satellite/GPS locations and movement pathways for Great White Heron #93445 in the GWHNWR, from capture date to 1 July 2010.

Figure 6. Capture location (yellow dot obscured by movement locations on Upper Harbor Key) and subsequent satellite/GPS locations and movement pathways for Great White Heron #68229 in the GWHNWR, from capture date to 1 July 2010.

Figure 7. Movements of 5 Great White Herons tagged with satellite/GPS transmitters in GWHNWR in 2010.

Figure 8. Locations of nesting colonies (red) and all Great White Herons (tan) and Great Blue Herons (blue) observed along foraging route surveys in Florida Bay in 2008 and 2009.

Figure 9. Locations of nesting colonies (red) and all Great White Herons (tan) and Great Blue Herons (blue) observed along foraging route surveys in GWHNWR in 2008 and 2009.

Figure 10. Minimum convex polygon in black encompassing all satellite/GPS locations of 5 Great White Herons tagged in the GWHNWR in 2010. This distribution of foraging habitats was used for use-versusavailability analyses.

Figure 11. Distribution and overlap of minimum convex polygons of 5 Great White Herons tracked with satellite/GPS transmitters in GWHNWR in 2010.

Figure 12. Minimum convex polygon and kernel volumes describing the activity range of Great White Heron #36312 tracked with a satellite/GPS transmitter in GWHNWR in 2010.

Figure 13. Minimum convex polygon and kernel volumes describing the activity range of Great White Heron #41246 tracked with a satellite/GPS transmitter in GWHNWR in 2010.

Figure 14. Minimum convex polygon and kernel volumes describing the activity range of Great White Heron #68229 tracked with a satellite/GPS transmitter in GWHNWR in 2010.

Figure 15. Minimum convex polygon and kernel volumes describing the activity range of Great White Heron #68231 tracked with a satellite/GPS transmitter in GWHNWR in 2010.

Figure 16. Minimum convex polygon and kernel volumes describing the activity range of Great White Heron #93445 tracked with a satellite/GPS transmitter in GWHNWR in 2010.