Cameras at the Boswell Energy Center near Cohasset and the Hibbard Renewable Energy Center in Duluth provide a closer look at the life of peregrine falcons, the fastest raptors on the planet. Minnesota Power installed the nesting boxes and cameras more than 200 feet up on stacks at the two power plants as part of a partnership with the Raptor Resource Project in Decorah, Iowa.
In a typical year, migrating peregrines return to the nesting boxes in March, the eggs are laid in mid-April and the chicks hatch in late May. The falcons are identified, banded and entered into a database which makes it possible to track the birds’ activities over their lifetimes, adding to what we know about this once-endangered species. Fifty-nine peregrines have hatched at Boswell since 1993 and 48 have been banded. At Hibbard, 10 chicks have hatched and been banded since 2008.
Power plants play a part in comeback
Use of the pesticide DDT nearly spelled the end of the peregrine falcon in Minnesota. But thanks to restoration efforts, the birds again nest in the state. In 1991, Minnesota Power installed a nesting platform 260 feet up a 400-foot stack at the Boswell Energy Center near Cohasset, and in 1993 it was home for the first two falcon chicks born in Itasca County since the mid-1960s. In 2008, the first peregrine chick was born at the Hibbard Energy Center in Duluth where another nesting box had been installed.
In the 1960s, use of the pesticide DDT nearly wiped out the entire population. In the early 1970s, DDT was banned and the American peregrine was declared an endangered species. Falconers, who are experts at handling, training and flying various birds of prey, have helped scientists re-establish the species in the United States.
Peregrines inhabit some of the earth's wildest and least accessible terrain. They are among the most widely distributed of birds, with nests on every continent except Antarctica. Peregrines are a migratory species whose winter vacation spots range from Little Rock, Arkansas to the tip of Argentina. They'll sometimes winter at a power plant if there's enough open water and an adequate food supply, such as pigeons, nearby.
Migrating peregrines usually return to Minnesota in March. The males return from the South first to reoccupy their nests. Females usually arrive from one to three weeks later, although some pairs spend the winter together and reach their nests at the same time. Peregrines mate for life. When one partner dies, the survivor finds a new mate.
To build nests and raise their families, peregrines seek cliffs, rock walls, tall buildings -- and more commonly in the Midwest, the tall stacks of power plants. They crave access to water, open country and open skies. Peregrines defend the sky all around their nests and will vigorously attack any threatening bird coming within a radius of about 500 feet. Some of their hunting territories measure up to twenty square miles. Nesting places are usually found at least two miles apart, except under conditions where prey is extremely abundant.
Falcons feed on pigeons, starlings, blackbirds, ducks, flickers, jays and doves. Falcons pursue their prey in the air and their long, sharp-cut wings are shaped for speed. The fastest raptor on earth, peregrines can dive at speeds of over 287 miles per hour. In level flight, they can achieve speeds of about 60 miles per hour.
Males and females exhibit the same elegant markings, but it’s possible to distinguish the sexes by size. Adult females, at weights of 1.9 pounds and more, look bigger and sturdier than the males, which can weigh less than 1.25 pounds. Peregrines are about the size and weight of a large crow.
Peregrines usually begin breeding at about 2 years of age. Females will lay a clutch of three or four eggs, though sometimes five are laid (and very rarely, six). The eggs hatch over 32 to 35 days. Chicks emerge from the shells covered with a short coat of white down and their eyes are open. Their leg muscles are weak, but their voices work very well and they cry out for food.
When the nestlings are tiny, their parents prepare “baby food” for them by plucking prey and shredding it with their beaks. As the youngsters grow up, the parents are more inclined to let them look out for themselves, but they do not leave them entirely on their own. Though the parents no longer serve them baby food, they continue to provide food for their young for up to two months after they leave the nest.
Peregrines usually make their first flight when they are about five or six weeks old, with males taking the leap before females. After the young falcons’ first flight, they are referred to as fledglings. It may take them a year or more to master the flying skills of their parents.
The first year of life is treacherous for young falcons; about 6 of every 10 peregrines hatched will die in their first year of life. Although they have a high mortality rate, peregrines have been known to live as long as 15 years.
The movement to save the peregrine falcon has a happy ending. The birds were removed from the Endangered Species List on August 20, 1999.