As a result, a kestrel at the top of an 18m-tall tree would be able to see clearly a 2mm-long invertebrate on the ground. Although hovering can be very effective in helping the birds see small mammals on the ground below, it uses a lot of energy, which is why the birds have developed other hunting techniques. Masters of the ambush, at dusk kestrels will often sit patiently waiting for house sparrows to start to roost, before rising up and striking.
As with so many birds of prey, kestrels have been persecuted over the years, especially when landowners realised they had a taste for pheasant chicks. Over one year period in the late s, one north Wales estate slaughtered 1, kestrels, drastically reducing the local population. Kestrels can be spotted in local parks, on the moors and hawking the edge of farmland.
But one of the most dramatic places to see it is along the coast, from the saltmarshes of Pagham Harbour in West Sussex, to the sand dunes of Formby Point in Lancashire and the beaches of Fife. On the coast, the kestrel can harness the breeze, says, using it to hover over a perfect habitat of rough grassland that hides a smorgasbord of small mammals. Craggy cliffs offer perfect nesting sites, while the milder seaside climate is good for invertebrates, from earthworms to beetles, which kestrels will happily prey on, especially during the winter.
A downside of the seaside habitats for kestrels is the saltwater wetness. Kestrels, like most birds, have trouble metabolising salt. Peregrines and short-eared owls also hunt the rough. These little falcons are generally located anywhere in the Western Hemisphere that is not covered in dense forest or in the Arctic Circle. American Kestrels are a species of open country, generally preferring grasslands and shrub lands over anything with tree cover.
Ideal kestrel habitat is composed of ample open space with snags, fence posts, lone bushes or trees, or power wires acting as isolated perches. Kestrels prefer to be able to see their entire territory easily from any one perch, and do not typically appear in areas with dense foliage. Thus American Kestrels can be found in any of the following: deserts, plains, wooded savanna, marshes, farmland, tree lines and foothills of mountains, clear-cut areas, and even suburban and urban environments.
While wintering, females are seen in more open habitat than males. Some hypothesize this is simply because the females generally arrive at wintering grounds before males do, and thus the females claim the more preferred habitat.
As one might expect from a bird with a wide range like the American Kestrel, this species is varied and adaptable when it comes to diet. The vast majority of prey taken by American Kestrels is medium or large insects. Most kestrels also frequently prey on small mammals, such as voles or mice, and small lizards and snakes. Kestrels are also known to occasionally hunt bats, though this is less common than the aforementioned prey items.
Kestrels use isolated perches to sit and wait for prey, and they also actively search while flying, kiting, or hovering over fields. Captured prey is then eaten by the kestrel while perching. American Kestrels differ from many other North American falcons in that they prefer to nest in cavities, instead of cliff ledges. Kestrels do not construct their own cavities, however, and thus they are secondary cavity nesters. Kestrels choose a variety of cavity types, including old woodpecker holes, squirrel nests, crevices in barns and building roofs, man-made nest boxes, or other similar structures.
American Kestrels do occasionally use old, sheltered bird nests, however this behavior is rare compared to cavity nesting. The male kestrel claims a nesting territory and identifies potential nest cavities. Males will escort potential mates to cavities within their territories and the female will choose the nest site.
Females appear to select males based on their plumage, flight displays, and how ideal their claimed nesting territory and potential nest cavities appear to be. Copulation between pairs is frequent and can occur from the time that both birds are at the nest site until the first egg is laid. Not all copulations are fertile, but they affirm the social bond between the male and female for the duration of the nesting season.
Females will lay anywhere from 1 to 7 eggs, with being the average. One egg is typically laid every other day, and incubation begins in full after the clutch is complete. The male or female may incubate the eggs briefly during the laying period, but incubation becomes a full-time job after the female is done laying eggs entirely.
The female typically performs the majority of the incubation, with the male hunting and bringing her food. The male will assist in incubation, however, and the female can hunt for herself on occasion as well. Incubation of the eggs typically takes days.
American Kestrel nestlings are born altricial, meaning blind and helpless. Though they are covered in a fine layer of white down, the down is not sufficient for thermoregulation, so the nestlings rely on the parents to keep warm.
Much like with incubation, the female performs most of the brooding, and the male provides most of the food, but the male and female will sometimes swap jobs.
The eggs were laid by Mrs Kes, a kestrel whose secret life I have been following via cameras hidden a nest box I made for her called Sycamore Stump. The average kestrel egg clutch is between three and six eggs, but it really depends on the weather and the body weight and general health of a female. Kestrels here at Fotherdale normally lay five eggs. The eggs are a red-brown, speckled colour and when they are first laid they are covered in a glistening mucus.
Kestrels normally lay in late April or early May, but again this depends on the weather. Kestrels lay one egg roughly every 48 hours, although it was two and a half days before Mrs Kes laid her second egg on April 8th.
She laid her third on April 10th, and her fourth on April 12th. Breeding begins April to may. The clutch of 3 — 6 eggs is incubated by the female and the chicks hatch after 27 — 31 days. The eggs measure around 39 millimetres by 32 millimetres. They are smooth and non-glossy and coloured white or yellowish-buff with red-brown markings.
Both adults feed the young birds, though the newly-hatched are usually fed by the female with the male hunting and bringing the food to the nest. Juveniles fledge after 27 — 39 days and disperse from their natal grounds in July — August and may travel up to miles kilometres.
Kestrels are not considered to be globally threatened and are the commonest bird of prey in Europe, although kestrels have declined in Britain in the last few years.
Image Source. More Fascinating Animals to Learn About. Galapagos Willet Bird. American Oystercatcher Bird. Galapagos Lava Gull Bird. British Moles.
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