Measurements
Both Sexes
- Length
- 8.7–12.2 in
22–31 cm - Wingspan
- 20.1–24 in
51–61 cm - Weight
- 2.8–5.8 oz
80–165 g
Relative Size
- Mourning Dove-sized; slightly smaller than a Merlin
Other Names
- Crécerelle d'Amérique (French)
- Cernícalo chitero (Spanish)
Cool Facts
- Sports fans in some cities get an extra show during night games: kestrels perching on light standards or foul poles, tracking moths and other insects in the powerful stadium light beams and catching these snacks on the wing. Some of their hunting flights have even made it onto TV sports coverage.
- When nature calls, nestling kestrels back up, raise their tails, and squirt feces onto the walls of the nest cavity. The feces dry on the cavity walls and stay off the nestlings. The nest gets to be a smelly place, with feces on the walls and uneaten parts of small animals on the floor.
- It can be tough being one of the smallest birds of prey. Despite their fierce lifestyle, American Kestrels end up as prey for larger birds such as Northern Goshawks, Red-tailed Hawks, Barn Owls, American Crows, and Sharp-shinned and Cooper’s Hawks, as well as rat snakes, corn snakes, and even fire ants.
- In winter in many southern parts of the range, female and male American Kestrels use different habitats. Females use the typical open habitat, and males use areas with more trees. This situation appears to be the result of the females migrating south first and establishing winter territories, leaving males to the more wooded areas.
- Unlike humans, birds can see ultraviolet light. This enables kestrels to make out the trails of urine that voles, a common prey mammal, leave as they run along the ground. Like neon diner signs, these bright paths may highlight the way to a meal—as has been observed in the Eurasian Kestrel, a close relative.
- Kestrels hide surplus kills in grass clumps, tree roots, bushes, fence posts, tree limbs, and cavities, to save the food for lean times or to hide it from thieves.
Habitat
Open Woodland
American Kestrels favor open areas with short ground vegetation and sparse trees. You’ll find them in meadows, grasslands, deserts, parks, farm fields, cities, and suburbs. The southeastern U.S. form breeds in unusual longleaf pine sandhill habitat. When breeding, kestrels need access to at least a few trees or structures that provide appropriate nesting cavities. American Kestrels are attracted to many habitats modified by humans, including pastures and parkland, and are often found near areas of human activity including towns and cities.
Food
Insects
American Kestrels eat mostly insects and other invertebrates, as well as small rodents and birds. Common foods include grasshoppers, cicadas, beetles, and dragonflies; scorpions and spiders; butterflies and moths; voles, mice, shrews, bats, and small songbirds. American Kestrels also sometimes eat small snakes, lizards, and frogs. And some people have reported seeing American Kestrels take larger prey, including red squirrels and Northern Flickers.
Nesting
Nesting Facts
- Clutch Size
- 4–5 eggs
- Number of Broods
- 1-2 broods
- Egg Length
- 1.2–1.5 in
3–3.8 cm - Egg Width
- 0.9–1.1 in
2.4–2.8 cm - Incubation Period
- 26–32 days
- Nestling Period
- 28–31 days
- Egg Description
- White to yellowish or light reddish-brown, mottled with violet-magenta, gray, or brown.
- Condition at Hatching
- Feeble, with sparse white down over pinkish skin; eyes partially open by first or second day.
Nest Description
American Kestrels do not use nesting materials. If the cavity floor is composed of loose material, the female hollows out a shallow depression there.
Nest Placement
Cavity
American Kestrels nest in cavities, although they lack the ability to excavate their own. They rely on old woodpecker holes, natural tree hollows, rock crevices, and nooks in buildings and other human-built structures. The male searches for possible nest cavities. When he’s found suitable candidates, he shows them to the female, who makes the final choice. Typically, nest sites are in trees along wood edges or in the middle of open ground. American Kestrels take readily to nest boxes (see Backyard Tips).
Behavior
Soaring
American Kestrels normally hunt by day. You may see a kestrel scanning for prey from the same perch all day long—or changing perches every few minutes. A kestrel pounces on its prey, seizing it with one or both feet; the bird may finish off a small meal right there on the ground, or carry larger prey back to a perch. During breeding season, males advertise their territory by repeatedly climbing and then diving, uttering a short series of klee! calls at the top of each ascent. Courting pairs may exchange gifts of food; usually the male feeds the female. Early in the pairing-up process, groups of four or five birds may congregate. You may see American Kestrels harassing larger hawks and eagles during migration, and attacking hawks in their territories during breeding season. Kestrels compete over the limited supply of nesting cavities with other cavity-nesters, and sometimes successfully fight off or evict bluebirds, Northern Flickers, small squirrels, and other competitors from their chosen sites.
Conservation
Least Concern
Although this is still the continent’s most common and widespread falcon, the American Kestrel is declining in some areas—such as in New England, parts of the Pacific Coast, and Florida, where the state lists it as a threatened species. Land clearing during the eighteenth and nineteenth centuries probably raised American Kestrel numbers substantially. By the 1980s there were an estimated 1.2 million kestrel pairs in North America. Modern-day declines stem from continued clearing of land and felling of the standing dead trees these birds depend on for their nest sites. The American Kestrel is also losing prey sources and nesting cavities to so-called “clean” farming practices, which remove hedgerows, trees, and brush. An additional threat is exposure to pesticides and other pollutants, which can reduce clutch sizes and hatching success. For kestrels in North America, a larger problem with pesticides is that they do their job, destroying the insects, spiders, and other prey on which the birds depend.
Credits
- Smallwood, J. A., and D. M. Bird. 2002. American Kestrel (Falco sparverius). In The Birds of North America, No. 602 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
- Dunne, P. 2006. Pete Dunne's Essential Field Guide Companion. Houghton Mifflin, New York.
- Elphick, C., J.B. Dunning, Jr., and D.A. Sibley. 2001. National Audubon Society Guide to Bird Life & Behavior. Alfred A. Knopf, New York.
Migration
Resident to long-distance migrant. In North America, the tendency for kestrels to migrate decreases from north to south, with southernmost populations resident year-round. While some American Kestrels migrate to Central America, the great majority spend the winter in the southern United States. Kestrels can often be seen along mountain ridges and at hawk watches during fall migration.
Backyard Tips
American Kestrels take well to artificial nest boxes. To attract a breeding pair, the box should be put up by early February. Nail it to a tree 10 to 30 feet above the ground away from traffic and loud human activity. Attach a guard to keep predators from raiding eggs and young. Find out more about nest boxes on our Attract Birds pages. You'll find plans for building a nest box of the appropriate size at our NestWatch site.
Find This Bird
Scan fence posts, utility lines and telephone poles, particularly when driving through farmland. Or catch them by the hundreds at coastal migration sites—such as Cape May, New Jersey, or Kiptopeke, Virginia—in September or early October. Particularly in summer, listen for their shrill killy-killy-killy call to be alerted to when they're around.