Though other birds of prey have been successfully reintroduced in U.S. cities, some local biologists and birdwatchers have doubts about the project, charging that the area is not remote enough from human activity and that the Hudson River, where the eagles will soon fish, is still dangerously polluted. They wonder whether the eagles will adapt to urban life as well as other raptors, including red-tailed hawks (Buteo jamaicensis) and peregrine falcons (Falco peregrinus), and will soon be seen soaring over midtowns skyscrapers on their seven-foot wingspans. (For more on how the eaglets are faring, see "From Wisconsin to the West Side.")
Alexander Brash, the chief of the Urban Park Rangers, admits that there is no record of bald eagles nesting in Manhattan in more than 300 years. Though the states bald eagle population has been steadily increasing since the late 1970s, the birds havent shown a fondness for urban real estate, preferring to nest in forested areas along the Hudson and Delaware Rivers. According to the New York State Department of Environmental Conservation, the nearest pair of nesting eagles is about 70 miles up the Hudson from New York City. Brash believes, however, that the eagles have a good chance of settling in Inwood Hill because the Hudson is cleaner than its been in years, and the park has tall stands of timber fully capable of holding nests. He hopes to release four young eagles in the same location each year for at least five years. "We think its an ideal species to bring back, a flagship for the citys efforts to restore the ecology of our parks," he says.
Devastation and Recovery
When Europeans first arrived in the 17th century, hundreds of thousands of bald eagles wandered the skies of North America. Then their numbers declined drastically as they became victims of hunting, and loss of prey and habitat, and, starting in the late 1940s, use of the pesticide DDT--which thinned the eagles eggshells and prevented hatching. By 1963 there were just 417 breeding pairs in the lower 48 states. After DDT was banned in 1972 and the Endangered Species Act was passed the following year, bald eagle recovery programs were launched across the nation by state and federal wildlife agencies, conservation organizations, and universities. These efforts led to a dramatic recovery of the population. Today, more than 6,000 bald eagle pairs nest in the lower 48 states, though bald eagles have seldom been seen nesting in cities.
The most promising precedent so far for reintroducing birds of prey to cities is that of the peregrine falcon, a swift, crow-size species that was also nearly driven to extinction by DDT. Starting in the early 1970s, captive-bred peregrines were released in cities such as Chicago, Atlanta and Baltimore, and they quickly adapted to urban life. According to Steve Sherrod, executive director of the Sutton Avian Research Center in Oklahoma, who has been involved for decades with reintroductions of peregrine falcons and bald eagles, skyscraper window ledges closely resemble the mountain cliffs where peregrines would normally nest, and pigeons--abundant in urban areas--are their favorite food. Though peregrines face unique hazards in a city, such as crashing into glass windows and falling down chimneys, they also benefit from having fewer predators. New York City now hosts one of the largest concentrations of peregrine falcons in the world, with pairs nesting on the Brooklyn Bridge and in the tower of Riverside Church.
Inspired by the successes with peregrines, several organizations are now reintroducing other birds of prey to urban areas. For example, barn owls (Tyto alba) were recently released on the grounds of the Pittsburgh Zoo and Aquarium. Since 1984, the Raptor Center at the University of Minnesota has been reintroducing ospreys (Pandion haliaetus) to the Twin Cities area. New Yorks Urban Park Rangers also released 24 eastern screech owls (Otus asio) in Central Park between 1998 and 2002, and two fledglings hatched this spring, offspring of the reintroduced birds.
The Urban Advantage?
If a raptor can tolerate the noise and bustle, cities offer abundant prey, a lower risk of being shot by hunters, reduced exposure to pesticides and a warmer climate than more rural areas. As a result, at least a dozen species of birds of prey now make their homes in urban areas. A pair of red-tailed hawks nest on a Milwaukee fire escape, and coopers hawks (Accipiter cooperii) hunt in Tucson golf courses and cemeteries.
The Earth Conservation Corps attempted the first-ever urban bald eagle reintroduction, releasing four eagles each June from 1995 through 1998 in the U.S. National Arboretum on the west bank of the Anacostia River in northeast Washington, D.C. They succeeded, with the help of a team of local inner-city kids, in bringing eagles back to the city after a 50-year absence. Currently a pair is nesting near the original reintroduction site, and the female is believed to be one of the birds the organization released several years ago. Now the corps is contributing its expertise to the Inwood release. "I think we showed the adaptability of the birds," says Bob Nixon, the organizations executive director.
Steve Sherrod says that a good eagle release site "doesnt necessarily have to be remote from human activity." He points out, for example, that eagles are happily nesting in a tree in the middle of an active gravel pit in Oklahoma. It can be challenging to find a suitable habitat for bald eagles in a city, but the advantage of an urban reintroduction, he says, is that more people can enjoy the birds and be educated by their presence.
Jennifer Uscher, a freelance science writer in New York, specializes in writing about birds.