From the April 2012 Conservationist
Photo: Barbara Saunders
On the Edge
The perils and rewards of banding peregrine falcons
By Barbara Allen Loucks
I wasn't expecting the blow to the back of my head. The adult female peregrine falcon took advantage of my back being turned and hit me hard in my helmet with her feet. I was entering the doorway going inside the top of the Kodak Tower in downtown Rochester, and had to stop for an instant, momentarily dizzy. We had just finished putting her young back in the nest box after banding, and she was demonstrating her displeasure at our intrusion.
The author climbing to reach a nest on a
Hudson River bridge. (Photo: Joe Bridges)
Peregrine falcons are notoriously aggressive around their eyries (or nest sites) during the breeding season, and the longtime resident female here had a reputation for being particularly unfriendly at our annual visits. As "wing man" for my colleague Mike Allen, I protected his shoulders and back with a broom and served as a target while he grabbed the young out of the nest box. We both wore eye protection. As an added precaution, another person stood behind me, trying to defend me from the swiftly diving adult female which would suddenly disappear and reappear, "kakking" loudly at times. We worked quickly to bring the young inside the building, and returned them to the waiting adults about a half hour later. Fortunately, adult males rarely attack, so we didn't have to ward him off as well.
Not too long ago, there wasn't a single peregrine pair nesting in New York State. The thinning of eggshells caused by DDT residues in their largely avian prey had eliminated this amazing raptor as a breeding bird from the entire east coast by the early 1960s. But through the release of captive-bred birds from The Peregrine Fund, active restoration programs were successful in reestablishing breeding populations (see "Back from the Brink" in the April 2005 Conservationist). In fact, in 2010, of 76 territorial peregrine pairs in New York, 54 successfully raised 144 young-the largest population in the eastern U.S.! Biologists banded 75 of these young. Since the species started nesting in the state again in 1983, hundreds of peregrine falcon chicks have been banded.
Placing a nest box at a bridge over
the Hudson River (Photo: NYS DOT)
I am fortunate to be part of a small group of DEC biologists who bands peregrines from NYC to Buffalo. The banding enables us to gather information-such as mortality (how, when and where they die), movements, dispersal and longevity-about the population. The vast majority of young peregrines are banded in the southeastern part of the state, particularly the New York City area. Christopher Nadareski of the New York City Department of Environmental Protection is a key cooperator with DEC. Sometimes, we get lucky and an adult female will refuse to leave the nest box. When this happens, we take the opportunity to capture and band her as well.
For safety and other reasons, we focus our banding efforts on the more easily reached peregrine nests on urban bridges and buildings, rather than nests located on cliff sites which are difficult to access. The perfect time to band the young is when they are about three weeks old. Their legs are then large enough to determine if the smaller male band (size 6) or larger female band (size 7a) is appropriate. Also, the birds are half-feathered and can't fly, which makes them less likely to try to evade capture.
An adult peregrine with a recently
hatched chick in a nest box on a
New York City bridge (Photo: Chris
Unlike most hawks and eagles, peregrines do not build large stick nests, but instead lay their brown eggs in shallow depressions (called scrapes) that the birds form in whatever substrate is available. On a cliff it could be dirt and small pebbles. On a bridge girder or building ledge, it could have rough debris or be quite bare. At the urban sites, biologists often place nest boxes that generally consist of a shallow tray about three feet square, a roof, three sides, and several inches of pea-sized gravel. These artificial nests help increase productivity by protecting the eggs from damage, such as rolling off the ledge.
On some bridges, temporary lane closures are necessary to allow biologists to climb above or below roadways to reach nests. At the Verrazano-Narrows Bridge in NYC, biologists and MTA Bridges and Tunnels employees (outfitted with safety harnesses, helmets and goggles) climb a series of ladders inside one of the two bridge towers, exiting at a point 693 feet above the water. It's exhilarating and unnerving at the same time, and you are rewarded with a commanding view of Staten Island, Brooklyn, New York Harbor and the Atlantic Ocean that few people are privileged to see.
At some sites, we need special equipment to reach the nest. For instance, in Albany, peregrines nest underneath one of the bridges over the Hudson River, so DEC biologist Nancy Heaslip works with the New York State Department of Transportation to use their snooper (a special truck with a bucket that goes over the side of the bridge) to reach the young peregrines. Across the state, DEC biologist Connie Adams once took advantage of the Darling Construction Company's offer to use their cherry picker to access a nest underneath the North Grand Island Bridge on the Niagara River. The picker was already on a barge being used for bridge cleaning.
Biologists banding a peregrine
chick in Rochester (Photo: Carol
During banding, every effort is made to minimize stress on the falcons (both young and adults), including trying to limit the time it takes to band them to a half hour or less. In most instances, the one to five young can be banded right at the nest box; occasionally, however, they have to be momentarily removed to a nearby location. Biologists check the health of all young, including inspecting their eyes, ears, throats, feathers and general condition. We attach two metal leg bands: a silver-colored U.S. Fish and Wildlife Service band is placed on the right leg, and a two-toned band with alphanumeric codes is placed on the left leg. Recent color bands used on NY-raised peregrines (and others in the northeast) are black and green or black and red. In addition, any unhatched eggs are collected for later analysis, and any desiccated prey remains are quickly checked and collected. If the box needs repairs after the nesting season, that is also noted. Interestingly, one NY study (C. Nadareski, pers. comm.) documented that the remains of more than 120 different species of birds, as well as an occasional bat, have been collected from the various nest sites over the years.
The workers who assist biologists during the banding process often feel a special connection to the project and gain a deeper understanding of the value of their efforts to help protect this species. During maintenance and renovation work, workers avoid unnecessary disturbance of nesting birds. Some facilities have installed webcams so that everyone can be involved. These sites are very popular and generally can be viewed from early spring through midsummer. Viewers can follow the nesting process from egg laying through the young birds leaving (fledging) the nest. Many people contact DEC to say how much they appreciate these armchair opportunities to observe peregrine falcons across the state. (See a listing of webcam sites.)
(Photo: Barbara Saunders)
Through our banding program, we've discovered that peregrine falcons hatched in NY have traveled to and successfully raised young in various places scattered between Massachusetts and Wisconsin, and from Ontario to Washington, D.C. as well. Released birds have nested as far west as Nebraska, and been seen as far south as Texas. One female peregrine from NYC was found dead in Atlantic City-it was 13+ years old.
In the years I've been banding peregrines, I've seen their population make great strides. They are graceful and powerful birds, and I never tire of watching them. It's amazing to see a peregrine tuck in its wings, go into a steep dive-peregrines can reach speeds of more than 200 mph-and then snatch a bird in midair. It's something you never forget.
Each time we visit a site, I get a thrill by what we're doing and am excited at what we see. But I always keep in mind to stay alert; after all, I am the unwanted guest in their home.
Barbara Allen Loucks is DEC's endangered raptor specialist.