Pencil drawing of a Kestrel, Falco sparverius; the most common raptor in the New World. The Bolivian subspecies is F. s. cearae, found from northeast Brazil south to eastern Bolivia.
The American Kestrel (Falco sparverius) is the smallest and most common raptor in North America. It has been confused with, and therefore called, a Sparrowhawk, to which it is similar in size. It is the largest of the species of Kestrels, and also has one of the largest ranges.
The difference between the female and the male, or tiercel, as he is known in some circles, is reflected more in plumage than in size. Males have blue-grey wings with black spade-like spots and white undersides with black barring. The back is rufous, with barring on the lower half. The breast and belly are off-white with black spade-like spots spotting. The tail is rufous, with a white or rufous tip and a black subterminal band.
The back and wings of the female are rufous with dark brown barring. The undersides of the females are creamy to buff with heavy brown streaking. The tail differs from that of the male's, being rufous with eight to ten heavy black bars. Juveniles exhibit coloration patterns similar to the adults’. In both sexes, the head is whitish beneath the eyes, where there are to be found two, vertical black facial markings, one in front and one just behind the eye, going down to the neck. Two black spots (ocelli) can be found on each side of the white or orangish nape, which are believed to be a form of natural mimicry, designed to appear as ‘eyes’ to deter predators. The wings are moderately long, fairly narrow, and taper to a point. although both sexes have a rufous back with noticeable barring. Juveniles are similar in plumage to adults.
The bird ranges in size from 12 to 27 cm (4.7 to 11 in) in length with a wingspan of 50–61 cm (20–24 in), the tail is 11–15 cm (4.3–5.9 in) and the tarsus is 3.2–4 cm (1.3–1.6) the female being the slightly larger of the pair. Males weigh 80–105 g (2.8–3.7 oz), while females weigh 100–120 grams (3.5–4.2 oz).
There are four known vocalizations; the klee or kill, the whine, and the chitter The klee is usually delivered as a rapid series – klee, klee, klee, klee when the kestrel is upset or excited. This call is used in a wide variety of situations and is heard from both sexes, but the larger females typically have lower-pitched voices than the males. The whine call is primarily associated with feeding. The chitter is used in activities which involve interaction between male and female birds, including courtship feeding and the feeding of nestlings. Nestlings can produce calls similar to those of adults at 16 days old.
In the wild birds that survive infancy are believed to live for five years or more, with the oldest record being that of a bird was 11 years and 7 months; captive birds have been known to live up to 17 years.
The bird is distributed from northern Canada to Tierra del Fuego, making use of a wide variety of environments, including prairies, grasslands, meadows, deserts. It thrives both in rural terrain and urban, and any area that provides perches, open space for hunting, and cavities for nesting suits it well. This kestrel is a bird of diverse habitat from spaces above the Arctic Circle to the tropics, from below sea level to elevations of over 4,500 meters (14,764 ft) in the Andes.
The American Kestrel's primary mode of hunting is by perching and waiting for prey to come near, but it also hawks by hovering in the air with rapid wing beats or perching and scanning the ground for prey, which consists largely of smaller birds, mainly sparrows, buntings, warblers; rodents such as mice and voles; lizards and small snakes, and; insects including grasshoppers and dragonflies. There is scant record of such kills as snakes, bats, and squirrels. Prey is almost always caught on the ground. Before striking, the kestrel characteristically bobs its head and tail, then makes a direct flight toward the prey to grab it in its talons.
Despite its small size and rather mundane hunting habits and choice of prey, it is a common bird to be used in falconry, especially by beginners; most falconers prefer larger birds such as Peregrine Falcons and Northern Goshawks when hunting, but Kestrels are easier to keep and breed than their larger kin.
It nests in cavities in trees, cliffs, buildings, and other structures. The female lays three to seven eggs, which both sexes help to incubate. American Kestrels are cavity nesters, but they are able to adapt to a wide variety of nesting situations. They generally prefer natural cavities (such as in trees) with closed tops and tight fitting entrances, as to provide for maximum protection of the eggs and young. Kestrels occasionally nest in holes created by large woodpeckers, or use the abandoned nests of other birds, such as Red-tailed Hawks, Merlins, and crows. They have been recorded nesting on cliff ledges and building tops, as well as in abandoned cavities in cactuses. American Kestrels also commonly utilize nesting boxes.Three to seven eggs (typically four or five) are laid approximately 24–72 hours apart. The average egg size is 32 mm by 29 mm, 10% larger than average for birds of its body size. The eggs are white to cream in color with brown or grey splotching. Incubation usually lasts 30 days and is mainly the responsibility of the female, although the male incubates 15–20% of the time. Eggs which are lost are typically replaced in 11–12 days. Hatching takes place over three to four days. Hatchlings are altricial, and are only able to sit up after five days. They grow very quickly, reaching an adult weight after 16–17 days. After 28–31 days, their wings develop and they are able to leave the nest.
The bird is distributed from northern Canada to Tierra del Fuego, making use of a wide variety of environments, including prairies, grasslands, meadows, deserts. It thrives both in rural terrain and urban, and any area that provides perches, open space for hunting, and cavities for nesting suits it well. This kestrel is a bird of diverse habitat from spaces above the Arctic Circle to the tropics, from below sea level to elevations of over 4,500 meters (14,764 ft) in the Andes.
The American Kestrel's primary mode of hunting is by perching and waiting for prey to come near, but it also hawks by hovering in the air with rapid wing beats or perching and scanning the ground for prey, which consists largely of smaller birds, mainly sparrows, buntings, warblers; rodents such as mice and voles; lizards and small snakes, and; insects including grasshoppers and dragonflies. There is scant record of such kills as snakes, bats, and squirrels. Prey is almost always caught on the ground. Before striking, the kestrel characteristically bobs its head and tail, then makes a direct flight toward the prey to grab it in its talons.
Despite its small size and rather mundane hunting habits and choice of prey, it is a common bird to be used in falconry, especially by beginners; most falconers prefer larger birds such as Peregrine Falcons and Northern Goshawks when hunting, but Kestrels are easier to keep and breed than their larger kin.
It nests in cavities in trees, cliffs, buildings, and other structures. The female lays three to seven eggs, which both sexes help to incubate. American Kestrels are cavity nesters, but they are able to adapt to a wide variety of nesting situations. They generally prefer natural cavities (such as in trees) with closed tops and tight fitting entrances, as to provide for maximum protection of the eggs and young. Kestrels occasionally nest in holes created by large woodpeckers, or use the abandoned nests of other birds, such as Red-tailed Hawks, Merlins, and crows. They have been recorded nesting on cliff ledges and building tops, as well as in abandoned cavities in cactuses. American Kestrels also commonly utilize nesting boxes.Three to seven eggs (typically four or five) are laid approximately 24–72 hours apart. The average egg size is 32 mm by 29 mm, 10% larger than average for birds of its body size. The eggs are white to cream in color with brown or grey splotching. Incubation usually lasts 30 days and is mainly the responsibility of the female, although the male incubates 15–20% of the time. Eggs which are lost are typically replaced in 11–12 days. Hatching takes place over three to four days. Hatchlings are altricial, and are only able to sit up after five days. They grow very quickly, reaching an adult weight after 16–17 days. After 28–31 days, their wings develop and they are able to leave the nest.
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