The common kestrel (Falco tinnunculus) is a bird of prey species belonging to the kestrel group of the falcon family Falconidae. It is also known as the European kestrel, Eurasian kestrel, or Old World kestrel. In the United Kingdom, where no other kestrel species commonly occurs, it is generally just called "kestrel".
This species occurs over a large range. It is widespread in Europe, Asia, and Africa, as well as occasionally reaching the east coast of North America. It has colonized a few oceanic islands, but vagrant individuals are generally rare; in the whole of Micronesia for example, the species was only recorded twice each on Guam and Saipan in the Marianas.
Common kestrels measure 32–39 cm (12+1⁄2–15+1⁄2 in) from head to tail, with a wingspan of 65–82 cm (25+1⁄2–32+1⁄2 in). Females are noticeably larger, with the adult male weighing 136–252 g (4+3⁄4–8+7⁄8 oz), around 155 g (5+1⁄2 oz) on average; the adult female weighs 154–314 g (5+3⁄8–11+1⁄8 oz), around 184 g (6+1⁄2 oz) on average. They are thus small compared with other birds of prey, but larger than most songbirds. Like the other Falco species, they have long wings as well as a distinctive long tail.
Their plumage is mainly light chestnut brown with blackish spots on the upperside and buff with narrow blackish streaks on the underside; the remiges are also blackish. Unlike most raptors, they display sexual colour dimorphism with the male having fewer black spots and streaks, as well as a blue-grey cap and tail. The tail is brown with black bars in females, and has a black tip with a narrow white rim in both sexes. All common kestrels have a prominent black malar stripe like their closest relatives.
The cere, feet, and a narrow ring around the eye are bright yellow; the toenails, bill and iris are dark. Juveniles look like adult females, but the underside streaks are wider; the yellow of their bare parts is paler. Hatchlings are covered in white down feathers, changing to a buff-grey second down coat before they grow their first true plumage.
In the cool-temperate parts of its range, the common kestrel migrates south in winter; otherwise it is sedentary, though juveniles may wander around in search for a good place to settle down as they become mature. It is a diurnal animal of the lowlands and prefers open habitat such as fields, heaths, shrubland and marshland. It does not require woodland to be present as long as there are alternative perching and nesting sites like rocks or buildings. It will thrive in treeless steppe where there are abundant herbaceous plants and shrubs to support a population of prey animals. The common kestrel readily adapts to human settlement, as long as sufficient swathes of vegetation are available, and may even be found in wetlands, moorlands and arid savanna. It is found from the sea to the lower mountain ranges, reaching elevations up to 4,500 m (14,800 ft) ASL in the hottest tropical parts of its range but only to about 1,750 m (5,740 ft) in the subtropical climate of the Himalayan foothills.
Globally, this species is not considered threatened by the IUCN. Its stocks were affected by the indiscriminate use of organochlorines and other pesticides in the mid-20th century, but being something of an r-strategist able to multiply quickly under good conditions it was less affected than other birds of prey. The global population has been fluctuating considerably over the years but remains generally stable; it is roughly estimated at 1–2 million pairs or so, about 20% of which are found in Europe. There has been a recent decline in parts of Western Europe such as Ireland. Subspecies dacotiae is quite rare, numbering less than 1000 adult birds in 1990, when the ancient western Canarian subspecies canariensis numbered about ten times as many birds.
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