What good is the warmth of summer, withou t the cold of winter to give it sweetness. ~J ohn Steinbeck
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A Little Help Here Many Wading Birds in State Now Considered Species of Concern By Samantha Collins of The Wetlands Institute
Snowy egret
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pend any time around a marsh, and you’ll come across a familiar sight: elegant, long-legged birds wandering among the grasses or hunting in the shallow water. These birds – herons and egrets – are some of the wetlands’ most iconic species. They belong to a group known as wading birds, which includes cranes, egrets, herons, storks, spoonbills, and ibises. Wading birds have physical and behavioral adaptions for living in wetland ecosystems, like extra-long legs to help keep feathers dry when wading through the water; toes that are thin and splayed to disperse their weight and prevent them from sinking in the mud; and bills designed for spearing fish or probing the mud for insects. Most wading birds nest in colonies, a strategy that gives each individual a better chance of escaping an intruding predator while tending to its nest. These nesting colonies are usually made up of different species of wading birds and are
Glossy ibis - photo courtesy of R. Guidetti
Seven Mile Times
Holiday 2020
often shared with other water-associated birds, like gulls and cormorants, as suitable nesting sites are increasingly in short supply. To help ensure reproductive success, these birds typically select nest sites in areas that are secluded from the mainland and its host of mammalian predators; within elevated areas to reduce the likelihood of nest flooding; and among vegetation that conceals adults and young while on the nest. New Jersey’s wading birds have experienced shifts in nesting abundance and distribution statewide, and many are now considered species of concern. Ongoing surveys indicate an overall decline in the number of nesting individuals and the number of active wading bird colonies statewide. Habitat loss associated with coastal development and increases in flooding within nesting areas are major concerns for these species. Sturgeon Island and Gull Island, located just north of The Wetlands Institute in the Seven Mile Island Innovation Lab,
are crucial nesting areas hosting more than 27% of all nesting wading birds in the state, based on statewide aerial surveys conducted in 2018. It is likely that the wading bird colony at the Stone Harbor Bird Sanctuary joined these colonies when they left the sanctuary and then Armacost Park. Nesting areas on these islands were created more than 70 years ago through the placement of dredged material on the marsh during operations to dredge the New Jersey Intracoastal Waterway. Wading bird species currently nesting on these islands include great egret, snowy egret, glossy ibis, black-crowned night heron, tricolored heron, and little blue heron. Historically, cattle egrets and yellow-crowned night herons were observed nesting in these colonies as well. Scientists at The Wetlands Institute are studying the nesting habits and success of wading birds on Gull and Sturgeon islands to understand nesting habitat preferences, causes and timing of nest
Great and snowy egrets feeding in a marsh pool.
loss, and changes in species abundance and distribution within and between seasons to better inform species conservation actions, as well as habitat management and enhancement plans. Studying these birds is no easy task but is necessary with limited information on nesting habits and success for these colonies. The dense vegetation at these sites limits detection of nesting birds from a distance, so trained staff must carefully survey and monitor pairs within the nesting area and limit the amount of time in the colony to reduce disturbance. Results from monitoring efforts during the 2019 and 2020 nesting seasons (April-August) show significant differences in nest success between nesting colonies, with the smaller nesting areas on Sturgeon Island experiencing lower nest success than the larger nesting areas on Gull Island. Nesting areas on Sturgeon Island tend to be closer to the water’s edge and at lower ground elevacontinued on page 70
Tricolored heron photo courtesy of R. Guidetti
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