Bald Eagle
Hudson River, New York
In 2001 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 had established itself, and consisted of 6 breeding pairs. Non-breeding and wintering eagles increased this number seasonally.
From 1890-1997, no breeding pairs of bald eagles were sighted in the Hudson River Valley. 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 the entire state of New York. In 1976 only one breeding pair remained. That year the NYSDEC began an aggressive reintroduction program, and the state population began increasing steadily. 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. From 1998-2001, Institute personnel 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 were captured, primarily for the collection of blood samples, which were 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 allowed state officials to identify potential threats to this recovering population.