About Kestrel
The name kestrel is given to several different members of the falcon genus, Falco. Kestrels are most easily distinguished by their typical hunting behaviour which is to hover at a height of around 10–20 m over open country and swoop down on prey, usually small mammals, lizards or large insects. Other falcons are more adapted to active hunting on the wing. In addition, kestrels are notable for usually having much brown in their plumage.
Kestrels require a slight headwind in order to hover, hence a local name of windhover for Common Kestrel.
Plumage often—but unusually for falcons—differs between male and female, and (as is usual with monogamous raptors) the female is slightly larger than the male. This allows a pair to fill different feeding niches over their home range. Kestrels are bold and have adapted well to human encroachment, nesting in buildings and hunting by major roads.
Kestrels do not build their own nests, but use nests built by other species.
Most species termed kestrels appear to form a distinct clade among the falcons, as suggested by comparison of mtDNA cytochrome b sequence data (Groombridge et al. 2002[1]) and morphology. This seems to have diverged from other Falco around the Miocene-Pliocene boundary (Messinian to Zanclean, or about 7–3.5 mya). The most basal "true" kestrels are three species from Africa and its surroundings which lack a malar stripe, and in one case have—like other falcons but unlike other true kestrels—large areas of gray in their wings.
Approximately during the Gelasian (Late Pliocene or Early Pleistocene, around 2.5–2 mya), the main lineage of true kestrels emerged; this contains the species characterized by a malar stripe. This too seems to have evolved in Africa and subsequently spread across the Old World until they reached Australia some time during the Middle Pleistocene, less than one million years ago. This group contains several taxa found on Indian Ocean islands.
More enigmatic is a group of 3 predominantly gray species from Africa and Madagascar. These are usually considered kestrels due to their general shape and habits, but are probably more quite distinct from the true kestrels as outlined above.
The American Kestrel is the only New World species termed "kestrel". Actually, the molecular data of Groombridge et al. (2002), as well as morphological peculiarities (like grey wings in males and a black ear-spot) and biogeography, strongly support the view that this species, among the Falco falcons, is not a kestrel at all in the phylogenetic sense but perhaps closer to the hobbies.
Malar-striped clade or Common Kestrel group
Madagascar Kestrel, Falco newtoni
Seychelles Kestrel, Falco araea
Mauritius Kestrel, Falco punctatus
Réunion Kestrel, Falco duboisi - extinct (c.1700)
Spotted Kestrel, Falco moluccensis, found in Indonesia
Nankeen Kestrel or Australian Kestrel, Falco cenchroides, found in Australia and New Guinea
Common Kestrel, Falco tinnunculus, found in Europe, Asia, and Africa
Rock Kestrel, Falco tinnunculus rupicolus, found in South Africa
Basal lineage(s) of true kestrels
Greater Kestrel, Falco rupicoloides, found in Eastern to South Africa
Fox Kestrel, Falco alopex, found in Equatorial Africa
Lesser Kestrel, Falco naumanni, found in southern Europe, India, and most of Africa except for the Sahara and equatorial forest areas
African gray kestrels (a more distant group)
Grey Kestrel, Falco ardosiaceus, found in Central to Southern Africa
Dickinson's Kestrel, Falco dickinsoni, found in Eastern to Southern Africa
Banded Kestrel, Falco zoniventris, found on Madagascar
American Kestrel
American Kestrel, Falco sparverius, found in North America and South America
The American Kestrel (Falco sparverius) is a small falcon. This bird was (and sometimes still is) colloquially known in North America as the "Sparrow Hawk". This name is misleading because it implies a connection with the Eurasian Sparrowhawk Accipiter nisus, which is unrelated; the latter is an accipiter rather than a falcon. Though both are diurnal raptors, they are only distantly related.
American Kestrels are widely distributed across the Americas. Their breeding range extends from central and western Alaska across northern Canada to Nova Scotia, and south throughout North America, into central Mexico, the Baja, and the Caribbean. They are local breeders in Central America and are widely distributed throughout South America.
Most of the birds breeding in Canada and the northern United States migrate south in the winter, although some males stay as year-round residents. It is a very rare vagrant to western Europe.
Description
The American Kestrel is the smallest falcon in North America—about the size of an American Robin. Like all raptors, the American Kestrel is sexually dimorphic, although there is some overlap within the species. The female ranges in length from 23 to 28 centimeters (9-11 inches) with a wingspan of 53–61 centimeters (21–24 inches) and weighs an average of 120 grams (4.2 ounces). The length of the male varies between 20–25 centimeters (8–10 inches) with a wingspan ranging from 51–56 centimeters (20–22 inches) and weighing an average of 111 grams (3.9 ounces). These subtle differences are often difficult to discern in the field.
The coloration of the feathers, however, greatly varies between the sexes. Males have blue-grey secondary feathers on their wings, while the undersides are white with black barring. The back is rufous in coloration, with barring on the lower half. The belly and flanks are white with black spotting. The tail is also rufous, except for the outer rectrix set, which is white with a black subterminal band.
The back of the female American Kestrel is rufous with dark brown barring. The wings exhibit similar coloration and patterning to the back. The undersides of the females are white with rufous streaking. The tail of the female is noticeably different from the male, being rufous in color with numerous narrow dark brown or black bars. Juveniles exhibit coloration patterns similar to the adults.
In both sexes, the head is white with a bluish-grey top. There are also two narrow, vertical black facial markings on each side of the head; one below the eyes and one on the rear portion of the auriculars. Two black spots (ocelli) can be found on each side of the white or orangish nape. The wings are moderately long, fairly narrow, and taper to a point. While perched, the wingtips are noticeably shorter than the tail tip.
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