American kestrel  (Falco sparverius)

Classified as Least Concern on the IUCN Red List (1) and listed on Appendix II of CITES (3).

Not only is the American kestrel one of the most abundant raptors in the Americas, but this diminutive bird of prey is also the only kestrel in the Western Hemisphere (4) (5). This colourful kestrel displays marked sexual dimorphism, with considerable variation between individuals also. Typically, the male has an orange back, flecked with black, a solid red tail with a wide, black tip, blue-grey wings and head cap, and black markings on the face and belly. The smaller female, however, lacks the blue-grey markings and has barred, brown upperparts and streaked underparts (2) (4) (6). This kestrel has rather short legs and toes, long, pointed wings and a compact, curved bill (4). Astonishingly, there are thought to be 17 different subspecies of the American kestrel with each varying in colour and size. The Cuban subspecies, Falco sparverius sparverioides, is the most distinctive, with two colour morphs; one is dark with red underparts, and the other with white underparts (2).  

The American kestrel is widespread throughout the Americas, from central Alaska and Canada, south discontinuously through the United States and Central America, to most of South America, excluding Amazonia. It is also found throughout the West Indies. During the breeding season, birds may be absent from some areas, due to a lack of large trees with nesting cavities, particularly in Mexico and Central America, and during the winter, those birds at the most northerly and southerly latitudes may migrate towards more temperate or tropical regions (4).

The American kestrel is found in almost every habitat within its large range, including tropical lowlands, urban areas and deserts, up to an altitude of around 3,700 metres in North America and 4,300 metres in South America (2). However, it is most abundant in lowland areas and open country with sparse trees or pylons, which provide roosts when it is foraging (5) (6).

The American kestrel prefers to hunt from an exposed perch, which offers a vantage point over open areas, from which it spots its prey using acute eyesight (2). Once its prey has been targeted, this sit-and-wait predator swoops down towards the ground to catch it in its talons, and kills the prey with bites to the head or neck (2) (4). It feeds mainly on large insects and small rodents in North America, but may feed more upon lizards in tropical regions. The American kestrel is also equally adept at catching flying prey out in the air and, like most other kestrels, also commonly hovers above the ground (2). Once captured, its prey may be eaten straight away, taken back to its perch and consumed, or cached for periods of unfavourable weather when hunting opportunities are limited (2) (4). 

Solitary for most of the year, the monogamous American kestrel forms breeding pairs between March and July in North America, with the timing of breeding varying across its range (2) (4). Like other true falcons (genus Falco), nests are not built, but old holes in trees, banks or cliffs or old magpie stick-nests are reused. In the northern hemisphere four to six white eggs with dense brown spots are laid, while in the Caribbean two to four are laid (2) (4). The eggs are incubated for around 28 to 32 days and the chicks will fledge after some 30 to 38 days in the nest. The young adults may breed after a year of age, with a life expectancy of almost ten years (2).

It is after the breeding season that many American kestrels migrate to spend winter in areas with higher food abundance. Birds at northern latitudes and juveniles tend to migrate significant distances, while birds in more tropical regions may remain fairly resident in the same area year-round (4). Populations in Alaska and Canada may migrate as far as Panama and Caribbean islands, and those birds breeding on Tierra del Fuego may migrate northwards to the South American mainland (4) (5).

Perhaps the commonest New World falconiform, the American kestrel is increasing in population and range (2). Some 1,200,000 breeding pairs are found in North America alone, with similarly large populations found in both Central and South America (2) (4) (7). This raptor, which prefers to forage over open habitat, has benefited from deforestation and wetland drainage across much of its range, particularly in Amazonia and in the United States during the 18^thand 19^thcenturies. It is also relatively tolerant of human disturbance and, consequently, readily occupies urban areas and nest boxes (2) (4). However, the American kestrel is in decline in parts of its range, most notably in eastern North America. The cause of this decline is unknown, but is likely due to a combination of contamination by toxic chemicals and pesticides, loss of habitat to reforestation, disease, and increased predation by other raptors (4) (5). It also occupies areas that are used for recreational hunting, and may be shot or trapped, and is also regularly killed in road collisions (4).

Although the American kestrel is not the focus of any specific conservation measures, it is found in a number of protected areas across its large range. Future priorities for the conservation of this species include further research into the effects of toxic contaminants and pesticides on its breeding success, behaviour and development (4).

ARKive is supported by OTEP, a joint programme of funding from the UK FCO and DFID which provides support to address priority environmental issues in the Overseas Territories, and Defra

For more information on the American kestrel, see:

• The Global Raptor Information Network:
  http://www.globalraptors.org/grin/SpeciesResults.asp?specID=8092

To find out more about bird conservation in the Americas, see:

• The American Bird Conservancy:
  http://www.abcbirds.org/
• The Neotropical Bird Club:
  http://www.neotropicalbirdclub.org/

For more information on this and other bird species please see:

• BirdLife International:
  http://www.birdlife.org