Department of Environmental Conservation

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Peregrine Falcon Program

two peregrine falcons perched
Photo by Mike Feller
Image of three falcon chicks standing on the ground
Eyasses (Falcon chicks)

History

Peregrine falcons are listed as an endangered species in New York State. They were eliminated as a nesting species in the state by the early 1960s, due mainly to pesticide (DDE) residues in their prey. The release of young captive bred birds from 1974-1988 helped lead to their return as a nesting species. Peregrines first returned to nest on two bridges in New York City in 1983. Two years later they were again nesting in the Adirondacks.

The population has grown steadily since that time:

  • By 2003 there were close to 50 pairs present statewide.
  • New York City may now have the largest urban population of peregrine falcons anywhere.
  • Peregrines nest on every Hudson River bridge south of Albany.
  • Peregrines currently nest on buildings or bridges in Albany, Syracuse, Rochester, Binghamton, and Buffalo.
  • There are about twenty pairs present in the Adirondacks on cliffs.
peregrine nest box on a bridge
Photo by Dave Gardner

Management

Many of these sites need annual management to protect the birds during the nesting season. For example, necessary bridge maintenance work must be conducted in a manner that does not prevent the falcons from nesting successfully. Falcons do not build stick nests like most hawks and the eggs can roll off bridge girders or get broken on window ledges. Wooden nest boxes filled with gravel are placed at many of the sites to increase productivity. These boxes need periodic replacement. Some Adirondack cliff climbing routes have to be closed for several months in the summer when they are too close to an active peregrine nest. This is both for the sake of the birds' nesting success and the safety of the climbers who may be dived on by the aggressive adults.

Due to all these human impacts, peregrine falcons will have to be protected for many years to come if we are to continue to enjoy their presence in New York.

Why Band Young Peregrine Falcons

Image of a man banding a young Peregrine falcon

Banding young peregrines provides important information on the birds' movements and is essential to understanding their habitat needs year-round. The nestlings are removed from the nest box or natural nest site for a short time and metal bands are placed on the birds legs. These bands are uniquely lettered and numbered so that if the falcons are observed later, or found injured or dead, they can be identified. When the birds are banded they are also checked for overall health and condition. Also, any unhatched eggs, egg shell fragments and prey remains are collected for examination. The unhatched eggs are checked for embryo development and analyzed for contaminants. The prey remains provide additional insight into peregrine falcon feeding habits.

Image of the black and red band with white lettering.

Because of the size difference of adult male and female falcons (females being larger) two different sizes of leg bands are needed. Banding is done when the nestlings are about three weeks old because they do not run out of the nest box or attempt to fly at this stage. In addition, at three weeks of age the young birds can be sexed by measuring the width of the legs.

Adult peregrine falcons, particularly the females, are quite aggressive during the banding operation. Individual birds vary in their level of aggressiveness, but many will fly very close to the bander and may even strike them with their feet! Biologists try to complete the banding process as quickly as possible to reduce stress on the birds.