Lake Milton Raptor Center

American Kestrel

- (Falco sparverius)
Classification
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Aves
  • Order: Falconiformes
  • Family: Falconidae
  • Genus: Falco
  • Species: Falco sparverius
  • Geographic Range

    Nearctic, Neotropical: The American kestrel permanently inhabits (without seasonal migration) North and South America from near the tree-line in Alaska and Canada and south to Tierra del Fuego. The bird can also be found in the West Indies, the Juan Fernandez Islands and Chile. It is largely absent from heavily forested areas, including Amazonia.

    Physical Characteristics

    male: 103g to 120g

    female: 126g to 166g

    Generally, the American kestrel is 19 - 21 cm in length with an average wingspan of 50 - 60 cm.

    Excepting the Seychelles kestrel, the American kestral is the smallest species in the genus Falco. There is a strong selection for sexual dichromatism, with males being brightly and rufously colored and females having a more even tone.

    Natural History

    Food Habits

    In the summer, American kestrels hunt in the early morning and evening, eating large insects (mainly grasshoppers). During winter, they hunt throughout daylight hours and eat small mammals (mice and sparrow-sized birds), sandpiper chicks, lizards, scorpions and amphibians.

    Reproduction

    For up to six weeks before egg laying, females are promiscuous, mating with two or three males. Once a female settles with one mate, the pair mate frequently until egg laying. Three to seven eggs are laid (usually 4 or 5) over a period of 2 or 3 days. Eggs are white, cream or pale pink with an average size of 35 x 29 mm. Laying dates vary with geographical location:

    Chile: September - October

    Trinidad: May

    Curacao: January

    Florida: mid-March - early June

    Central USA: mid-April - early June

    Canada: late May - mid-June

    The female does most of the incubation, but males have been known to occasionally sit. Both sexes have brooding patches. Incubation lasts 29 - 30 days and hatched chicks are non-competitive. Once chicks have hatched, females beg food from males. The female, in turn, feeds the young for the first 20 days. After that period, chicks beg for food from males and feed themselves. After 30 days, chicks leave the nest. The family remains as a unit for some time. The survival rate of chicks is about 50% under natural conditions, but it is usually higher under better conditions (e.g., human-provided nesting boxes).

    Behavior

    The American kestrel is, for the most part, not a social bird. During the mating season, males and females pair up and have joint territories. Presumably, the pair or the male defends the territory. The function of the territory may not be so much to ensure mating as to maintain a pair bond during the nesting season when the male is needed to help rear offspring.

    Habitat

    The American kestrel nests in tree cavities, woodpecker holes, crevices of buildings, holes in banks, nest boxes or, rarely, old nests of other birds. The American kestrel is highly adaptable behaviorly and lives just about everywhere, as long as there is some open ground for hunting and conspicuous places on which to perch (e.g., telephone wires).

    Biomes: taiga, temperate forest & rainforest, temperate grassland, chaparral, desert, tropical deciduous forest, tropical scrub forest, tropical savanna & grasslands, mountains

    Economic Importance for Humans

    The American kestrel plays a prominent part in controlling creatures that humans usually consider a nuisance (mice, insects, etc.).

    Conservation

    Status: no special status

    The availability of nesting places (tree-cavities) may be the chief density limiting factor in breeding populations of American kestrels. This density can be increased by the installation of nesting boxes. However, whether or not additional nesting boxes are introduced, the bird is common.

    Other Comments

    The common name "sparrow-hawk" is a misnomer because the diet of Falco sparvarius is not even close to being exclusively made up of sparrows. Its other common name, "American kestrel," is more appropriate.



    American Kestrel American Kestrel