For the Birds Radio Program: American Kestrel
Our tiniest and loveliest falcon is often seen from roads and highways.
Transcript
The “most light-hearted and frolicsome,” “the prettiest and jauntiest of our hawks, and yet no prig,” are phrases two ornithologists of past generations, William Brewster and Elliot Coues, used to describe the American Kestrel. This lithe creature weighs a mere four ounces, yet how elegantly that weight is distributed! Its svelte body is supported in airy space by dainty, slender wings measuring twenty-four inches from tip to tip that flick back or flutter through the air in delicate, buoyant flight, or spread and widen to allow the kestrel to sail in circles on a thermal. The kestrel’s distinctive, delicate shape makes it easy for experienced birders to identify even in silhouette. But the experience of seeing a kestrel is even better when you get a look at its bright rufous back and tail, and the slate blue wings on the male. The striking markings on its face enhance its lovely plumage.
Kestrels are quieter in August than in spring and early summer, but occasionally we can still hear their “killy killy killy” call, which is as distinctive as their plumage. The somewhat similar call of the closely related European Kestrel may have led to the etymological origin of their name. The word kestrel is apparently related to a French word which originally referred to a leper’s clicket–a clapper used to warn people of a passing leper, which reminded some of a kestrel’s call.
Kestrels are probably seen most often in farm country, along two-lane highways and interstates, but more and more are turning up in urban parks. They usually sit on utility wires or fences in the characteristic pose of falcons, which has been described as “hunched up and frowning.” While hunting they often hover, furiously beating their wings but staying in one spot as they scrutinize the ground in hopes of discovering a grasshopper, mouse, or other small prey animal.
By August, kestrel families are splitting up. Adults lead solitary lives most of the year, and after fall migration often defend winter territories, apparently so they won’t have to share during the season of shortage.
August begins the most dangerous time in a kestrel’s life. About 75% of all kestrel deaths occur between August and November, based on banding studies. There are records of kestrels being killed by blue jay and crow attacks, cats, cars, lightning, hitting windows, power lines, and transmission towers, and even run over by locomotives, but most banded birds that are found dead have been shot. Most kestrels don’t survive until their first birthday, and the average life expectancy at hatching is only a year and three months. But kestrels that successfully negotiate that dangerous first year dramatically increase their life expectancy. Banding data indicates that the oldest known kestrel survived to be 13 years 7 months.
Interestingly, young birds that hatch out in a given season often join together in small flocks which stay together through their first migration, possibly to stave off some of those potential hazards. Most kestrels that pass through Minnesota are headed for the central and southern U.S. and Mexico, but some do spend the entire winter right here. They are often found even during extremely cold winters near grain elevators, eating mice and sparrows attracted to spilled grain.
During August and September, as kestrels wend their way south, it isn’t too hard to find them in open areas around the metro area. But if you want to see them in numbers, head up to Lake Superior. On peak days during the next two months, as many as 250 will pass by Hawk Ridge in Duluth. Their biggest numbers coincide with large dragonfly flights. And on those days, they’re often spotted snatching dragonflies in midair and pulling their talons to their beaks to munch as they wing past. How will you know if a peak day is coming? Usually the best flights happen on days with fair skies and winds with a westerly component.