Potential Avian Predators of Piping Plover (Charadrius melodus): A Study at Fire Island, NY


The Piping Plover (Charadrius melodus) is a federally-threatened shorebird that relies on nesting habitat along the Atlantic Coast, including in New York. A variety of management strategies to protect nesting plovers at Fire Island, NY, target mammalian predation, but the impact of avian predation remains largely unknown. During the summer of 2022, at Robert Moses State Park (RMSP) and the National Park Service (NPS) Lighthouse, I recorded abundance and behavior of raptors, gulls, corvids, blackbirds, and shorebirds of other species (i.e., Ruddy Turnstone, Arenaria interpres, and American Oystercatcher, Haematopus palliatus) that are known or suspected to take (predate upon) Piping Plover adults, chicks, or eggs. This work was as part of the Virginia Tech Shorebird Program’s annual monitoring of plovers on Fire Island. Before the chicks can fly at around 25 days of age and are considered fledged, they are especially vulnerable to predation. During routine monitoring activities, I made instantaneous counts of potential avian predators while in plover nesting areas from early June to mid-August and recorded their habitat (e.g., intertidal, wrack line, dry sand), behavior (e.g., loafing, foraging), and flock size. Gulls were the most abundant potential avian predator and were observed daily (Great Black-backed Gull, Larus marinus = 122.1 birds/day; Herring Gull, L. argentatus = 58.0 birds/day; and Lesser Black-backed Gull, L. fuscus = 35.5 birds/day), though VTSP researchers and I detected little evidence of gulls taking plovers in 2022. Peregrine Falcons (Falco peregrinus) were seen infrequently (0.3 birds/day), but were observed hunting nesting shorebirds, including confirmed takes of plovers. Based on my observations, I constructed a map of avian predator density across the area monitored in relation to locations of Piping Plover nests and broods for the months surveyed. Overall, the density of potential avian predators increased throughout July and August, likely as these species finished breeding and dispersed. To investigate the impact of avian predator abundance on chick survival before fledging, I modeled the probability of chick disappearance prior to fledge using avian predator abundance and hatch date as explanatory variables. I predicted that avian predators with more evidence of predation on plovers would have a larger negative effect on chick survival. This model should also aid our understanding of whether certain types of avian predators have a larger effect on chick mortality than others. In this study, I characterized the avian predator community present at Robert Moses SP and the NPS Lighthouse and begin to clarify the impact of these avian predators on chick survival. Understanding the species, numbers, and distribution of avian predators present can inform future management decisions.



Ecology, Piping Plover (Charadrius melodus), Fire Island, NY, Avian Predators, Shorebirds, Peregrine Falcon (Falco peregrinus), Ornithology, Threatened and Endangered Species, Population growth, Barrier island, Mortality, Spatiotemporal distribution, Conservation and management, Fledging success, Trophic interactions, Productivity