Master of Environmental Studies Capstone Projects

Document Type

Thesis or dissertation

Date of this Version

2021

Abstract

The southern coast of New Jersey is home to several endangered bird species including the least tern (Sternula antillarum) and piping plover (Charadrius melodus). The populations of these two species of shorebirds are declining rapidly, essentially because of human activities. In recent decades, coastal development in southern New Jersey and an influx of human residents and visitors to the region have severely degraded this beach habitat. In addition to human disturbances on their nesting areas, predation from mammals and avian species are one of the most influential factors that determine the survival of these endangered ground nesting birds. The primary avian species of concern include gulls and corvids, notably the American crow (Corvus brachyrhynchos) and the fish crow (Corvus ossifragus) which are pervasive avian predators of shorebird eggs and chicks in this coastal area. Both corvids and gulls have been able to thrive in human developed areas due to their ability to exploit food, habitat, and other resources created by humans that benefit their survival. To deter the impact of corvid predation, one technique that requires more research is the use of scare tactics such as effigies. Studies have shown that crows have the ability to discern death of their own species and will avoid an area that they perceive to be dangerous (Swift & Marzluff 2015). The Nature Conservancy (TNC) of New Jersey developed a plan to research the effectiveness of crow effigies as a source of predation management. The hypothesis is that once crows are conditioned with bait to feed at a specific location, they will no longer approach the bait at that location once an effigy is introduced. If successful, effigies will be used to diminish corvid presence near nesting sites which will thus reduce predation on tern and plover eggs and chicks. Although this hypothesis was not able to be tested due to sustained interruptions from gulls and an absence of data because crows did not consistently visit bait plots, a combination of research from the literature review as well as firsthand observations are used to formulate recommendations for revisiting this study with more success in the future. Better understanding of corvid behavior and their responses to effigies will support conservation organizations as they attempt to mitigate threats and challenges posed by these natural avian predators.

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Date Posted: 15 December 2021