The Institute for Wildlife Studies completed a three-year project with the New York State Department of Environmental Conservation (NYSDEC) concerning the ecology of both wintering and breeding bald eagles along the Hudson River. The project was conducted along approximately 150 miles of the Hudson River, from just north of New York City northward to Glens Falls. This area includes a wide variety of habitats, ranging from industrial areas to undeveloped island parks. Within this mix a small, resident eagle population has established itself, and currently consists of 6 breeding pairs. Both non-breeding and wintering eagles increase this number seasonally.
For over 100 years the Hudson River Valley has been without a breeding bald eagle population. Once common, the birds were slowly pushed out by increasing development until 1890, when the last breeding pair was sighted. Over the next 80 years, eagle numbers steadily declined throughout New York State until 1976, when only one breeding pair remained. That year the NYSDEC began an aggressive reintroduction program, and the population has been steadily increasing ever since. However, it wasn’t until 1992 that a breeding pair was sighted along the Hudson River.
In 1998, the NYSDEC contracted the Institute to investigate the ecology of wintering and breeding eagles within the Hudson River Valley. Since 1998, Institute personnel have spent hundreds of hours observing eagles along the river to better understand eagle nesting success, habitat selection, diet, and interactions with humans. A total of 42 eagles have been captured, primarily for the collection of blood samples, which are tested for various contaminants known to be present in the Hudson River. Several of the captured eagles were equipped with satellite transmitters or conventional radio transmitters to track their movements along the river. Along with observational data, this information will allow state officials to identify potential threats to this recovering population.