The American kestrel, once plentiful across much of our nation’s countryside, including the rural farms and fields of Ohio, has been in decline for a decade or more. In fact, many raptors have been showing widespread, long-term declines. According to Dr. Laurie Goodrich, director of Raptor Monitoring at Hawk Mountain, in Pennsylvania, these declines are often associated with a loss of habitat due to increased development, changing agricultural practices and chemical use that reduces the bird’s prey or that may poison the birds themselves.
“Raptors like owls, hawks and falcons, including the American kestrel are beneficial predators around farmland and agricultural areas. They eat mice, voles, lizards, large pest insects and even snakes,” says Dr. Goodrich. “A family of barn owls can eat around 3,000 rodents during a summer.” Often hunting as a family group, a family of kestrels can eat around 500 voles and mice a year, in addition to snakes, grasshoppers and other insects. Their preferred prey consists mostly of small rodents and lots of insects.
“They are especially fond of grasshoppers and consume a large number of these crop-damaging insects during the summer months,” says Goodrich. Kestrels are not known for feeding on carrion, so you won’t see them lighting on road-killed animals.
The aerodynamic little raptor used to be called a sparrow hawk in the past, but the kestrel is actually a small falcon and is closely related to the peregrine falcon. About the size of a blue jay and weighing only 3 to 6 ounces, these little falcons can often be seen perched overhead on utility lines, watching and waiting to swoop down and capture some unsuspecting prey on the ground. One of the kestrel’s unique features is its ability to hover when on the hunt for prey. The birds flap their wings rapidly, keeping them stationary and airborne, as they search the ground for their target prey. Increasing their effectiveness as hunters, kestrels can see ultraviolet light — colors that are invisible to the human eye.
“When I was a kid growing up, we would drive to Lake Erie and would see lots of kestrels on the wires. Over the last decade, it’s much rarer to see one,” said Jim McCormac, avian education specialist with the Ohio Division of Wildlife. One factor that has limited the kestrel’s breeding success is the lack of adequate nesting sites. “There’s intense pressure for cavity nesting species,” says McCormac.
American kestrels do not build nests but rely on cavities previously made by woodpeckers or naturally occurring holes in trees. Dead trees removed from woodlots and yards reduce the possible sites for cavity nesters. Kestrels do, however, readily accept man-made nestboxes. When such boxes are provided, kestrels can be attracted to an area where their preferred habitat surrounds the nesting area. Kestrels also show a great deal of nest site fidelity, returning to the same nests year after year.
The bird’s prime habitat is open country with accessible perching locations. This includes meadows, grasslands, farmlands, open fields and pastures, large orchards and vineyards, and mowed roadsides. They prefer to hunt in short grass. Several states have initiated American Kestrel Highway Nestbox Trails, including Tennessee, Iowa, New Jersey and Ohio. “Kestrels search for insects and other food in large, open areas of short grass, a habitat type that is common along highways,” says Amanda Duren, program coordinator for the Ohio Bird Conservation Initiative (OBCI).
The OBCI, in collaboration with the Ohio Ornithological Society, American Kestrel Partnership, Ohio Division of Wildlife and Ohio Department of Transportation, have joined forces to take advantage of the unconventional but plentiful habitat along highway rights-of-ways. The kestrel highway nestbox project utilizes this available habitat by installing nestboxes on the backs of highway road signs. “When the boxes are mounted to the metal I-beams of the signs, it also discourages predators from gaining access to the boxes,” adds Duren.
“We currently have a total of 41 boxes mounted on road signs in Wyandot and Crawford counties. We’d like to expand that number across the state,” says Duren. In 2013 volunteers monitoring the boxes counted eight young kestrels, and in 2014 that number increased to 22. “The counties chosen for the initial start-up of the program were those that were historically prairie areas. These areas are where kestrels once found suitable habitat and were prevalent in the past,” says McCormac, who helped initiate the highway nestbox project.
Private landowners with adequate habitat in rural and agricultural communities can play a significant role in helping the American kestrel’s numbers recover by erecting nestboxes on their land. “Many farmers want to take advantage of the benefits raptors contribute to rodent and pest control around their farms. And many landowners simply like the idea of helping the birds out and enjoy seeing them on their land,” says Dr. Goodrich.
An additional factor contributing to the decline of raptors in some areas is poisoning by chemicals, notably rodenticides or rat poisons. Raptors tend to accumulate higher concentrations of toxic chemicals in their bodies when they feed on poisoned prey. These rodent control formulations contain strong amounts of anticoagulants that cause an animal to bleed to death slowly. “A poisoned rodent wandering around out in the open becomes prey for a hunting raptor,” adds Dr. Goodrich.
Rural landowners who mount nestboxes shouldn’t be discouraged if a pair of kestrels doesn’t move into the box the first year. It sometimes takes a few years for a pair to lay claim to a nestbox. Once a pair has successfully nested in a box, they often return to nest in that box year after year. Placing the box in an ideal location in their preferred habitat increases the likelihood the box will be used.
Building, erecting, monitoring and observing a kestrel nestbox can not only be a very rewarding experience and help reduce the decline of our smallest falcon, but can also provide an enormous benefit to the nontoxic rodent and pest control around our farms and fields.
For additional information on kestrel biology, nestbox plans, monitoring, and maintenance, visit http://kestrel.peregrinefund.org, www.hawkmountain.org, andhttp://wildlife.ohiodnr.gov (search for nestbox plans), or contact the Ohio Division of Wildlife at 800-WILDLIFE (945-3543) and ask for Publication 419. To make a donation to the Ohio Highway American Kestrel Nestbox Trail, visit www.gofundme.com/obcikestrels.
For the online version of this article you can visit: http://www.countryliving.coop/departments/keeping-ohios-kestrels/