EAGLE COUNTY — Peregrine falcons may well be the rarest raptor in Eagle County. Eagle County probably has a couple of nesting sites that are inhabited by peregrine falcons. The location of the photos accompanying this story will not be revealed to protect these birds.
At one time peregrine falcons were on the endangered species list! The use of DDT as a pesticide caused a rapid decline of many raptors from 1950 to 1970 due to the thinning of the eggshell. Those eggshells broke during incubation and dramatically reduced the population. Pesticide bans, impressive projects focused on recovery, captive breeding, the Peregrine Fund and other efforts allowed the species to recover enough to be removed from the endangered species list in 1999.
The peregrine, Falco peregrinus, is a remarkable bird. It is found on every continent except Antarctica. The birds that nest on the tundra of North America winter in South America — that means they travel 15,500 miles each year, the longest migration of any North American species. In fact, the species name “peregrine” means wanderer.
For as many as a 1,000 years, some cultures have trained falcons to hunt and the peregrine has been prized for their ability by falconers. This is because this bird feeds on other birds, which gave it another name, the duck hawk. It is a very fast flier at up to 35 mph when it is cruising and 70 mph when pursuing prey in a level chase. But their most impressive speed occurs in a hunting stoop. That is a dive from as much as 2,500 feet. National Geographic measured one bird in a dive at around 240 mph when it captured a pigeon.
Peregrine nest sites are usually in cliffs, which make them more difficult to find than osprey and bald eagles that have huge nests in trees in open areas along rivers. Peregrines will nest in elevations as high as 12,000 feet. There are also many nests on skyscrapers and bridges in cities across the U.S. Basically, any location where there is a reliable supply of birds will do. They have been documented taking large birds like sandhill cranes, fast birds like swifts, and small birds like hummingbirds. In some areas, bats are common prey. They also may feed on rodents, snakes, lizards and will steal food from other raptors.
These birds have a wingspan of 3.3 to 3.6 feet. In flight, falcons are easily identified because they tend to fly with their wings slightly bent back. Adult birds are a slate gray and have black and white areas. The breast is white and the underside of the wings is barred. One of the best identifying characteristics is often described as “cheek-wedges.” This black area has the appearance of a black helmet over the head. Often the first clue there is a peregrine in the area is a distinctive “reek, reek reek” call.
Peregrine nests are somewhat unique and are called a scrape. That is because they don’t build anything. They simply find a secluded, protected area on a cliff and scrape out the sand and gravel on a ledge to create a nest site around 9 inches in diameter and a couple of inches deep. They have been known to use the abandoned nests of other birds and even nest on the ground where there are steep slopes.
The birds are believed to mate for life. Records indicate they may live more than 15 years. The female will lay from two to five creamy brown, blotched eggs. After 30 to 35 days, the chicks will hatch out. They will only weigh a couple of ounces, have eyes closed, white down and are basically helpless. Only the females incubate the eggs, but both birds obtain the food to feed the young.
Observing one of these birds is a real treat, but one you will probably have to work hard to experience.
Rick Spitzer is the author of “Colorado Mountain Passes,” published by Westcliffe Publishers and available at The Bookworm of Edwards, Amazon and many stores across the state. The book provides photos and text about the history, lore, wildlife and scenery around the passes of Colorado.