American Kestrel

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Common Name: American Kestrel
Scientific Name: Falco sparverius

Size: 8.7-12.2 inches (22-31 cm); Wingspan: 20.1-24 inches (51-61 cm)

Habitat: North America; its breeding range extends from central and western Alaska across northern Canada to Nova Scotia, and south throughout North America, into central Mexico and the Caribbean. It is a local breeder in Central America and is widely distributed throughout South America. Most birds breeding in Canada and the northern United States migrate south in the winter. It is an occasional vagrant to Western Europe.

American Kestrels occupy habitats ranging from deserts and grasslands to alpine meadows. They are most likely spotted perching on telephone wires along roadsides, in open country with short vegetation and few trees. 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.

Status: Least Concern. Global population: 4,000,000 adult individuals. The American Kestrel is North America’s most common and widespread falcon but populations have been declining everywhere except in the central United States. According to the North American Breeding Bird Survey, between 1966 and 2010 they declined by an estimated 1.5 percent per year, amounting to a cumulative decline of about 48 percent. Partners in Flight estimates the global breeding population at 4 million, with 13 percent breeding in Canada, 31 percent residing in the U.S., and 10 percent in Mexico. They rate an 11 out of 20 on the Continental Concern Score and are not on the 2012 Watch List. Current 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 destroy the insects, spiders, and other prey on which the birds depend.

Diet: Grasshoppers, lizards, mice, and small birds. It typically hunts by hovering in the air with rapid wing beats or perching, intensely scanning the ground for prey. 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.

Nesting: Females are noticeably larger than males. They are one of the most colorful of all raptors. They are pale when seen from below and warm, rusty brown spotted with black above, with a black band near the tip of the tail. Males have slate-blue wings while the females’ wings are reddish brown. Both sexes have pairs of black vertical slashes on the sides of their pale faces—sometimes called a “mustache” and a “sideburn." Juveniles resembles adults, although their breasts whiter and have some streaked feather patterned as opposed to the adult black-dotted feather patterning.

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 will take readily to nest boxes. American Kestrels do not use nesting materials. If the cavity floor is composed of loose material, the female hollows out a shallow depression there. Females lay 4-5 white to yellowish eggs, mottled with violet-magenta, gray, or brown spots. Incubation lasts 26-32 days with nesting lasting approximately another 30 days. The chicks are born with sparse white down over pinkish skin and their eyes partially open by first or second day.

Cool Facts: It is the smallest falcon in North America and often called the “Sparrow Hawk”. This “Sparrow Hawk” name is mistakenly connected with the Eurasian Sparrowhawk, which is in the genus Accipiter.

Although not as aggressive a hunter as many other larger falcons, it has with occasional success against birds, hunted prey up twice their own weight. It can be tough being one of the smallest birds of prey. Despite their fierce lifestyle, they 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.

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.

Seventeen subspecies of the American kestrel are recognized, generally based upon plumage, size, and vocalizations:

  • F. s. sparverius, described by Linnaeus in 1758, is the nominate subspecies. It is found in most of the United States, Canada, and Mexico.
  • F. s. paulus, described by Howe and King in 1902, is found in the Southeast United States, from Louisiana to Florida.
  • F. s. peninsularis, described by Mearns in 1892, is found in southern Baja California.
  • F. s. tropicalis, described by Griscom in 1930, is found from southern Mexico to northern Honduras.
  • F. s. nicaraguensis, described by Howell in 1965, is found in Honduras and Nicaragua.
  • F. s. sparveroides, described by Vigors in 1827, is found in Cuba and the Isle of Youth, and southern to central Bahamas.
  • F. s. caribaearum, described by Gmelin in 1788, is found in Puerto Rico through the Lesser Antilles to Grenada.
  • F. s. ochraceus, described by Cory in 1915, is found in eastern Colombia and northwest Venezuela.
  • F. s. caucae, described by Chapman in 1915, is found in western Colombia.
  • F. s. aequatorialis, described by Mearns in 1892, is found in northern Ecuador.
  • F. s. peruvianus, described by Cory in 1915, is found in southwest Ecuador, Peru, and northern Chile.
  • F. s. fernandensis, described by Chapman in 1915, is found on the Juan Fernández Islands off Chile.
  • F. s. cinnamominu, described by Swainson in 1837, is found in Peru, Chile, and Argentina.
  • F. s. cearae, described by Cory in 1915, is found from northeast Brazil south to eastern Bolivia.

This 3D model is found in Songbird Remix Birds of Prey Volume I: Kestrels, Hobbies and Falcons

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