BLANE KLEMEK COLUMN: Make no mistake, American kestrels are popular raptors
The American kestrel, sometimes called "sparrow hawk," is not a hawk at all. Certainly the bird's pint-sized frame is small, thus "sparrow," but the "hawk" in the common name is actually a misnomer. The bird of prey with pointed wings and beautiful plumage is actually a very small falcon.
In fact, American kestrels are the smallest falcon in North America, not to mention being smaller than any hawk. Here's an unbashful raptor that resides in a wide variety of habitats, will readily accept the accommodations of artificial nest-boxes and is common throughout most of Minnesota. Kestrels are perhaps the most easily recognized and frequently observed raptor.
No other bird of prey in North America is so richly colored. Male kestrels sport a rusty back and tail, slate blue adorns his crown and wings and a white terminal band tips his tail. White cheek patches are accented by two black "whisker" markings on each side of his head. Total length is about 10 inches long and averaging slightly less than 4 ounces in weight. Not much for size, but any shortcoming are compensated by force and fearlessness.
Their diet is surprisingly general for such small falcons. Unlike other falcons, which capture most of their prey in the air (birds), kestrels capture much of their prey on the ground, though not always. Species of mammals make up about 70 percent of their diet, including rodents such as young ground squirrels, gophers, shrews, voles, mice and rats. Even young cottontail rabbits are preyed upon.
Birds, about 10 percent of their total diet, are hunted, too. About 20 percent include insects such as grasshoppers, crickets, beetles, butterflies, moths, dragonflies and worms, make up a significant part of a kestrel's diet, and just 1 percent of their diet consists of reptiles and amphibians like snakes, salamanders, frogs and toads.
A familiar kestrel habit will often give human admirers a good clue toward positive identification. Kestrels typically hunt by hovering in a near motionless—save for their fluttering wings—above grassy fields, ditches or other likely small-rodent haunts. The raptor's longish tail will be fanned, the body angled slightly upward, and the head tilted downward with eyes intensely riveted and searching for the movements of prey beneath tall vegetation.
Aided by headwinds, this mode of flight will be maintained indefinitely, occasionally dipping abruptly a few feet lower in altitude, only to regain the sedentary airborne posture if prey had yet to be sighted or secured. A complete free-fall to the ground below will occur if a hapless vole, mouse, or grasshopper fails to miss the clutches of the falcon's quick strike.
As it is, kestrel couples form their annual bonds through courtship rituals comprised of flights and calls. Soon after the male establishes or reestablishes a territory, he will perform numerous flights to fair heights above the trees and dive while emitting loud "klee, klee, klee" notes, typically at the apex of his display. He may also carry food to his mate and feed her.
The ceremony is designed to strengthen the ties that bind. And soon after copulation, egg laying and incubation commences. Somewhat unique for birds of prey where most of the incubation duties are carried out by females, male kestrels pitch in and share in this lengthy task.
Generally anywhere from three to seven eggs are laid that hatch in about a month's time.
When the chicks at last hatch, both parents begin hunting non-stop in order to satisfy the appetites of their growing offspring. After fledging, the kestrel family will remain intact for about a month until their fully grown youngsters begin their lives as independent adults as we get out and enjoy the great outdoors.
Blane Klemek is a Minnesota DNR wildlife manager. He can be reached at firstname.lastname@example.org.