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Nature Notes: Peregrine Falcon

Ed Robinson
December 5, 2023

How things have changed! When I was young, mankind was still of the mindset that the natural world existed mostly for our pleasure and exploitation, and we were hell bent upon control of everything around us. Our chemical industries were hard at work inventing new products to kill every possible irritating insect and we were either ignorant or uncaring about the damage caused to humans or the environment. Many readers of my generation will remember planes flying over neighborhoods to release sprays that were intended to eliminate pests like mosquitos. I recall long flights to New Zealand and Australia in the 1970s where stewardesses would walk down the aisles spraying insecticides over our heads before we could deplane into the terminals.

Marine biologist Rachel Carson is credited with starting a sea change in attitudes with her seminal book of 1962, Silent Spring, writing about the damage that chemicals such as DDT were causing to humans and the natural world. She began her research work in the 1950s when she learned of U.S. Department of Agriculture programs for aerial spraying of insecticides mixed with fuel oil to help control fire ants. She gathered convincing scientific evidence that accumulations of DDT were causing birds to lay fragile eggs that could not survive the nesting process. Carson must have been influenced as well by a bout of breast cancer in 1960 that forced her to undergo a mastectomy and radiation therapy.

small gray and tan raptor bird looks at camera

Peregrine Falcon (iStock photo by JAH)

We now know that Carson and other scientists were correct. Altered public opinion forced the banning of DDT and a new regulatory approach to chemicals used in the environment. But the damage had already been severe for any number of bird species, one of them the spectacular Peregrine Falcon. Of nearly 20 recognized sub-species worldwide, the Eastern Peregrine (Falco peregrinus anatum) was eliminated from our region. Fortunately, there is good news as these superb fliers have made a strong recovery with more than a little help from humans.

The birds were never present in our region in large numbers, but many more Peregrines were observed passing through coastal areas during spring and autumn migration periods. In the definitive Birds of Maine by Peter Vickery, the author notes historical sightings of around 10 breeding pairs in Maine each summer, mostly found on high cliffs along the coast. In those days, the birds were not often spotted nesting in urban areas as occurs today, since falcons like most other raptors are sensitive to human disturbance during the breeding and nesting season. By the 1960s there were no nesting reports of Peregrine Falcons in Maine and the birds did not return until the late 1980s.

This is a fierce looking but beautiful bird by any standard, with slate gray back and wings, light colored chest and neck with thin bands of dark brown. Dark eyes are set off by a yellow eye ring, while black talons contrast with yellow feet. The hooked beak has a notch that allows the Peregrine to shear the spine of a captured bird before tearing off hunks of flesh. The body ranges up to 24 inches long in the much larger female with a wingspan up to 48 inches and a weight of nearly four pounds. Even at that size, it is amazing to understand this bird can rocket down upon a target at speeds over 200 miles per hour, knocking its prey senseless in the air.

The name peregrine derives from the Latin word for “foreign,” but over time has been taken to mean “pilgrim” or “wanderer.” That certainly applies to this bird since they have the widest global range of any raptor. They may be found from sea level to over 12,000 feet in elevation, from the far northern tundra of North America and Asia to South America, Australia, and South Africa. While some Peregrines undertake annual migrations of 15,000 miles, a few of our nesting birds remain on Maine’s cliff faces through harsh winters. I was thrilled to see the birds in distant Patagonia, Costa Rica, and recently on Virginia’s Chincoteague Island.

The Peregrine used to be considered a denizen of wild places, particularly remote mountain ledges far from human habitation. In recent decades, as their population has recovered thanks to aggressive captive breeding programs, Peregrine Falcons have found they can live well in urban areas. It is now common to find the birds nesting on skyscrapers in major cities, with rock pigeons easy pickings around urban parks. Strategically mounted cameras adjacent to nest sites have helped build public awareness and support for continued efforts to protect these birds.

In the late 1960s several groups raised funds to begin captive breeding of Peregrines for later release into the wild. Notable among them were The Peregrine Fund, the Santa Cruz Predatory Bird Research Group, and the University of Minnesota Raptor Center. The birds were placed on the federal Endangered Species list in 1973 and while they were delisted in 1999, they are still listed as endangered in Maine. Thanks to the breeding programs, nearly 150 Peregrines were released in Maine between 1984 and 1997. Peregrine Falcons observed here today are generally descendants of those released birds or members of the Tundra subspecies moving through the region.

Maine’s Department of Inland Fisheries and Wildlife (IF&W) continues an active monitoring program for Peregrines and is nearing completion of an updated conservation plan set for release in 2024. During the years 2019-2021 observers visited every Maine site that had been known to host breeding Peregrine Falcons, a significant challenge given that many sites are quite remote. The 2022 study of the most active sites revealed 32 pairs of birds and a yield of 53 chicks. The recent 2023 results showed 30 Peregrine pairs, with 17 successful nests and a yield of 37 chicks, below 2022 but in line with earlier years in the study. It is interesting to note that 11 of the successful nests were at urban sites like Bath Iron Works and the Casco Bay Bridge in Portland.

Scientists visit nesting sites from the middle of March into the autumn, when juvenile Falcons may still be visible near their birth locations even if adults have moved on. They found birds as far north as Mt. Kineo on Moosehead Lake, west to Grafton Notch, at a quarry in Belfast, at the Ram Island Ledge Lighthouse, at Skowhegan’s Sappi Mill and at the Precipice in Acadia National Park. The Precipice was used to capture and place leg bands on three birds for longer term observation. Unfortunately, one of those juveniles was later fatally struck by an automobile in Pennsylvania.

While the Peregrine Falcon is in better shape today than it was 60 years ago, the birds still need considerable assistance to continue their recovery in the face of ongoing development, pollution, and loss of habitat. Agencies like IF&W take a variety of steps to lend a hand, including signage near nest sites, seasonal trail closings, and cooperation with rock climbing groups to limit disturbance during breeding season. Nest boxes have been used with success at some locations to offer the birds protection from severe weather or predation, and to assist scientists with observation and banding efforts. Active communications efforts are made to educate the public using various forms of social media. In one case, IF&W was called to rescue a young bird that ended up in an Ellsworth toy store, with a successful release.

It is difficult for scientists to provide firm population numbers for the far-flung Peregrine Falcon but Cornell’s Birds of the World reports a best current estimate of 2,000-3,000 pairs across North America. With the protection of the Migratory Bird Act and ongoing public education efforts, Peregrines probably have better prospects here than in some countries where raptors are still considered pests to be eliminated whenever possible.

Rachel Carson suffered a fate that was quite common among breast cancer patients in the 1960s when the tumor spread throughout her body despite medical treatments. She lived until April 1964, long enough to see a ground swell of support for her arguments and to win numerous awards and prizes despite ferocious opposition from the chemical industry and their supporters. In her last wishes, Carson asked that half of her ashes be spread along the shore of Squirrel Island, near the Sheepscot River in Maine. It would be nice to think of Carson these days looking down at Maine’s coastline to enjoy the sight of the magnificent Peregrine Falcons soaring high before stooping to their prey far below.

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