The American kestrel (Falco sparverius), colloquially known as the sparrow hawk, is North America's smallest and most prevalent falcon. Exhibiting a striking sexual dimorphism, the female is moderately larger than the male. Both sexes boast a rufous back with distinct barring, but it is the male that carries the more colorful plumage, with blue-grey wings adorned with black spots and a white underbelly marked with black barring. The female, on the other hand, displays a rufous back and wings with dark brown barring and a creamy to buff underside with heavy brown streaking. Juveniles mirror the adult plumage closely.
Males can be identified by their blue-grey wings with black spots and the rufous tail with a single black subterminal band. Females, however, have rufous wings with dark brown barring and a tail marked with numerous narrow dark bands. Both sexes have a white face with a bluish-grey cap and two vertical black facial markings on each side of the head, which is unique among falcons. The presence of two black spots on the nape, resembling false eyes, is a distinctive feature of this species.
The American kestrel thrives in a variety of open to semi-open landscapes, including grasslands, meadows, deserts, urban, and suburban areas. Its habitat must provide perches, open spaces for hunting, and cavities for nesting.
This falcon's breeding range spans from central and western Alaska across northern Canada to Nova Scotia, and south throughout North America into central Mexico and the Caribbean. It is also a local breeder in Central America and is widely distributed throughout South America. Birds breeding in Canada and the northern United States often migrate south for the winter.
The American kestrel is an adaptable hunter, often perching and scanning the ground for prey or hunting from the air. It is known to hover with rapid wing beats before diving to capture prey. This species is also recognized for its energy-conserving hunting methods.
The kestrel's vocal repertoire includes the "klee" or "killy," a rapid series when excited, the "whine" associated with feeding and copulation, and the "chitter" used in social interactions between males and females.
Kestrels are cavity nesters, laying three to seven eggs that are incubated by both sexes. They exhibit strong pair bonds, often reusing previous nesting sites. The breeding season sees males performing dive displays to attract mates.
While similar in appearance to other kestrels, the American kestrel is genetically closer to larger American falcons such as the peregrine. Its unique plumage and size differences between sexes help distinguish it from other raptor species.
The diet of the American kestrel is diverse, including insects like grasshoppers, lizards, mice, and small birds. Its broad diet has contributed to the species' success across a wide range of environments.
The American kestrel is classified as Least Concern by the IUCN, though some regional populations have experienced declines. Conservation efforts include monitoring programs and the establishment of nest boxes to support breeding populations.
The American kestrel is a popular choice for beginner falconers due to its manageable size and adaptability. While not as powerful as larger falcons, with proper training, kestrels can effectively hunt smaller birds like sparrows and starlings.