EVANSVILLE − Few animals capture the imagination like peregrine falcons with their dramatic appearance and lightning speed.
Considered the fastest animal on earth, peregrine falcons dive on their prey at speeds up to 200 mph, capturing them in flight. Prey is snatched out of the air or knocked senseless.
“Aesthetically, they are a really handsome bird. Unlike a lot of birds, falcons are big enough that people can see them easily,” said John Castrale, a wildlife biologist.
A medium-sized hawk about the size of a crow, adult peregrines have a distinctive dark hood and moustache, with a cream-colored throat, blue barring and yellow soft parts. In flight, the wings and tail are long and pointed, and the head is relatively large.
Castrale knows a thing or two about peregrine falcons. He retired in 2014 from his longtime position as Indiana state ornithologist but remains active as a board member of the Midwest Peregrine Society.
Thirty years ago this year, Castrale oversaw the reintroduction of peregrine falcons in Indiana, including the 1994 release of 15 of the birds from a rooftop in Downtown Evansville. With names such as River Ace and Phoenix, the release drew a lot of fanfare. It was the last round of releases in the state’s reintroduction campaign, which began in 1991 and included releases in Indianapolis, Fort Wayne and South Bend. A total of 60 young falcons were released in Indiana.
While peregrines are well established in Indiana now, none are currently known to be nesting in Evansville, said Allysin Gillet, state ornithologist at the Indiana Department of Natural Resources.
The closest, she said, is at the AES power plant in Petersburg, Indiana. “We have around 14 territories with pairs – so around 28 nesting,” she said.
Most of those are concentrated along Lake Michigan, with one nest in Fort Wayne, two in Indianapolis, one in Petersburg and one in the Anderson/Muncie, Indiana, area. The reason for this, Gillet said, is that peregrines are partially migratory and often move south in winter. They also frequent areas with water, preying on waterfowl. So much so, that Gillet said falcons were once commonly called duck hawks.
Although the hope when the peregrines were originally released was that they would imprint on their locations and remain, staying in one place just isn’t in their nature, Gillet said.
“They have distributed themselves across the state. A lot of them here now are from Wisconsin, Illinois and Ohio,” she said. “They are more abundant than what they were before. There are 50 pairs (nesting) in the Midwest and about 17 to 20 in Kentucky. There are probably 300 or more total in the Midwest now."
Castrale said peregrines have a large range, with females moving up to 200 miles on average and males 100 miles.
Few historical records of peregrine falcons in Southern Indiana exist, Castrale said.
“The only records of them are at a rock quarry in Southeastern Indiana and in the 1800s on the Wabash down in Southwest Indiana where they nested in the hollows of dead trees,” Castrale said.
Urban releases mimicked this natural habitat with tall buildings and structures.
“We viewed it as part of a contribution to the entire Midwest restoration,” Castrale said.
With their hooked beaks and fierce looks, it’s easy to think of peregrines as apex predators but their survival has been as precarious as the building ledges and rocky heights where they often lay their eggs unprotected by a nest.
“It’s really hard as a raptor to survive the first year. It’s estimated 65 to 85 percent die,” Gillet said.
Not only must young peregrines learn to hunt and feed themselves but they too can be prey for larger predators, particularly great horned owls.
“They don’t use traditional bowl-shaped nests but they lay their eggs on ledges in debris and crevices in what’s called a ‘nest scrape,’” Gillet said.
This leaves the eggs and the young birds more exposed to hazards such as a simple fall, the elements and predators. Providing nesting boxes for them in locations where they are known to reside has been one way of successfully mitigating this problem.
And then there is the human impact. In 1970, the U.S. Fish and Wildlife Service listed peregrine falcons in North America as an endangered species as their population declined primarily because of habitat loss and pesticide contamination (mainly DDT) that affected their ability to reproduce. By that time they were listed as endangered, no peregrines had been known to be nesting east of the Mississippi River for five years.
However, with the reduction in DDT use and efforts to restore the peregrine population through the release of young captive-bred birds. The peregrine falcon was removed from the federal endangered species list in 1999 although it continues to be protected under the federal Migratory Bird Treaty Act. It is still listed as a species of special concern in Indiana.
So where did the peregrine falcons released in Evansville go?
The male River Ace was found to be nesting a power plant in Southwestern Ohio in 2002. A female, Phoenix, was found injured from a gunshot in Floyd County near the Interstate 64 bridge in New Albany, and later died. Another Evansville-released female ended up in Fort Wayne, Castrale said.
“They can’t be pinned down,” he said.
Gillet said the DNR would love to know if any peregrines are sighted in the Evansville area.