Peregrine Falcons: Fierce predators rescued from the abyss

What predatory bird can guide a screaming 200 MPH freefall dive to intercept a flying duck, killing it with a blow from a fist of talons? Tornado winds howl at 200MPH. Even flying horizontally, this bird can accelerate to 70MPH. No animal is faster. It must therefore be a falcon, in today’s case, the Peregrine Falcon. This species inhabits all continents but Antarctica. The Peregrine likes cliff ledges for nesting, such as the high basalt walls at the Birds of Prey Refuge along the Snake River near Boise. In such places, listen for its call, which is very similar to this Prairie Falcon:

Kevin Colver recording: Songbirds of the Southwest Canyon Country

Fifty years ago, the Peregrine Falcon was in a different dive, a plunge to extinction. The culprit was DDT. It wasn’t poisoning the birds, but it insidiously interfered with birds’ calcium metabolism, leaving thin-shelled eggs that broke under brooding parents. DDT is persistent. Worse, DDT bioaccumulates in fats of species high on the food chain, birds like falcons, eagles, and pelicans. Robins provided the first persuasive evidence of DDT bioaccumulation.

On December 28, 1973, President Nixon signed the Endangered Species Act into law. The peregrine falcon was immediately listed. DDT use in the United States was banned. Worried wildlife researchers undertook a bold program to rescue intact eggs from cliff-face nests. The captive nestlings were raised up and taught to hunt. Over the years, 1600 peregrines were released into the wild. The peregrine’s population plunge was halted, then reversed. In 1999, it was formally delisted. By 2003, 3000 pairs bred in Canada, the U.S. and Mexico. Peregrines have never been common, but today, you are four times more likely to see a Peregrine Falcon in Utah than 30 years earlier. You can see similar rebounds in Red-tailed Hawks, Brown Pelicans and other predatory birds by going to the website of the National Audubon Christmas bird counts. This is an environmental success story worth celebrating.

This is Linda Kervin for Bridgerland Audubon Society.

Credits:

Photo: Courtesy & Copyright Kent R. Keller and

Courtesy images.fws.gov

Text: Jim Cane, Bridgerland Audubon Society

Bird Recordings Courtesy and Copyright Dr. Kevin Colver,https://wildstore.wildsanctuary.com/collections/special-collections & WildSanctuary, Soundscapes, http://www.wildsanctuary.com

Additional Reading:

Peregrine Falcon (Falco peregrinus), U.S. Fish & Wildlife Service, May 2006, http://library.fws.gov/ES/peregrine06.pdf

Christmas Bird Count, National Audubon Society, http://birds.audubon.org/christmas-bird-count

The Birder’s Handbook: a field guide to the natural history of North American birds : including all species that regularly breed north of Mexico [Book] by Paul R. Ehrlich, David S. Dobkin, Darryl Wheye
http://www.amazon.com/Birders-Handbook-Natural-History-American/dp/0671659898

Feathers: The Evolution of a Natural Miracle, Thor Hanson, Illustrated. 336 pages. Basic Books.
http://www.amazon.com/Feathers-Evolution-Natural-Thor-Hanson/dp/0465028780/

Salt Lake City Peregrine Falcon Cameras, Wildlife.utah.gov, http://wildlife.utah.gov/dwr/learn-more/peregrine-cam.html