Biology
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İngilizce
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The diet of the grey kestrel consists of insects, such as grasshoppers, flying termites and ants, as well as small reptiles, rodents, birds, bats and even earthworms. It may also eat oil palm fruits, one of only three raptor species known to do so. Hunting is usually undertaken from a high, open perch, with the kestrel taking prey from the ground or from low foliage, though it may also chase birds and insects in flight (2) (4) (5). Nesting usually occurs between January and April in West Africa, and between August and October in Kenya, Tanzania and Angola (2), the breeding pair often taking over Hamerkop (Scopus umbretta) nests, even evicting the residents, or using tree cavities or old stick nests (2) (4) (5). Two to five eggs are laid, hatching after an incubation period of between 26 and 31 days. Fledging occurs after approximately 30 days (2) (4).
Conservation
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The grey kestrel is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that international trade in grey kestrels should be carefully monitored and controlled (3). However, there are no other known conservation measures currently in place for this species.
Description
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The grey kestrel is a fairly small and stocky bird of prey with, as its common name suggests, entirely slate grey plumage, which contrasts strongly with its bright yellow eye ring, cere, legs and feet. The head is large, with a heavy black beak and brown eyes, the wings are fairly short and pointed, and the ends of the primary flight feathers are blackish (2) (4) (5). Potentially confused with the sooty falcon, Falco concolor, the grey kestrel is more heavily built, with shorter wings, which do not reach the end of the tail when the bird is perched (4) (6). Male and female grey kestrels are similar in appearance, but males are about three-quarters the size of the female, while juveniles can be distinguished by the brown wash to the plumage, the paler abdomen, and pale green facial skin (2) (4) (6). The grey kestrel flies with fast, shallow wing beats, interspersed with short glides, usually low over open ground or among trees, but hovering is not commonly seen. The call is a shrill keek-keek-keek, given at the nest, and sometimes a whistling scream (4) (5).
Habitat
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The grey kestrel inhabits woodland, wooded grassland and savanna, including palm savanna, often near clearings and burnt areas, where it regularly hunts (2) (4) (5). It can be found at elevations of up to 1,800 metres (4).
Range
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Most of sub-Saharan Africa, from Senegal east to Ethiopia and Eritrea, and as far south as Namibia, Zambia and Malawi (2) (4) (7). The grey kestrel is mostly sedentary, but may make some seasonal movements in parts of West Africa (4).
Status
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Classified as Least Concern (LC) on the IUCN Red List (1) and listed on Appendix II of CITES (3).
Threats
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The grey kestrel has a wide distribution and a large global population, and is not currently considered at risk of extinction (7). Grey kestrels are thought to readily adapt to human land-use, often hunting on agricultural land and possibly even benefitting from forest clearance (2) (4).
Grey kestrel
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İngilizce
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wikipedia EN tarafından sağlandı
The grey kestrel (Falco ardosiaceus) is an African bird of prey belonging to the falcon family Falconidae. Its closest relatives are the banded kestrel and Dickinson's kestrel and the three are sometimes placed in the subgenus Dissodectes.
Description
It is a fairly small, stocky kestrel with a large, flat-topped head and fairly short wings that don't reach past the tip of the tail when at rest. It is 28–33 cm long with a wingspan of 58–72 cm and a weight of up to 300 grams. The female is 4-11% larger and 5-11% heavier than the male. The plumage of the adult is uniformly dark grey apart from darker wingtips, faint dark streaking on the body and slightly barred flight feathers. The feet and cere are yellow and there is bare yellow skin around the eye. The most similar species is the sooty falcon which has a more rounded head, long wings extending past the tail and less yellow around the eye.
Juvenile grey kestrels are browner than the adults with a greenish cere and greenish around the eye. Juvenile Dickinson's kestrels are similar but have a barred tail and a more strongly barred underwing.
The grey kestrel is generally silent outside the breeding season but has a shrill, chattering call and a rattling whistle.
Habitat and range
It inhabits savannas, open woodland and forest clearings. It favours areas with palm trees, especially near water. It often perches on exposed branches, telegraph poles and wires.
It is widespread in West and Central Africa but is absent from densely forested regions including parts of the Congo Basin. Its range extends east to Ethiopia and western parts of Kenya and Tanzania. In the south it reaches northern parts of Namibia and Zambia and vagrants have appeared in Malawi. The total range covers about 12 million km2. In West Africa there is some movement northward in the wet season and southward in the dry season.
Behaviour
It is a crepuscular bird, most active at dawn and dusk. It generally hunts from a high perch but occasionally hovers. It feeds mainly on insects, lizards and small mammals such as bats[2] but will also take birds, amphibians and worms. Prey is usually caught on the ground. It will sometimes feed on oil palm nuts, one of the few birds of prey to eat vegetable matter.
Breeding occurs from March to June in the north of its range and from August to December in the south. Courting pairs perform mutual soaring displays. The eggs are usually laid in the nest of a hamerkop; most often an unoccupied nest but occasionally hamerkops will be forced out. Sometimes the kestrels will use the nest of another bird or a hole in a tree. There are two to five eggs in a clutch. They are whitish with reddish or brown markings and are incubated for 26–31 days. The young birds fledge after about 30 days.
References
- Ferguson-Lees, James & Christie, David A. (2001) Raptors of the World, Christopher Helm, London.
- Global Raptor Information Network (2007) Species account: Grey Kestrel Falco ardosiaceus. Downloaded from http://www.globalraptors.org on 2 Aug. 2007.
- Sinclair, Ian & Ryan, Peter (2003) Birds of Africa south of the Sahara, Struik, Cape Town.
- Zimmerman, Dale A.; Turner, Donald A. & Pearson, David J. (1999) Birds of Kenya & Northern Tanzania, Christopher Helm, London.
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Grey kestrel: Brief Summary
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İngilizce
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wikipedia EN tarafından sağlandı
The grey kestrel (Falco ardosiaceus) is an African bird of prey belonging to the falcon family Falconidae. Its closest relatives are the banded kestrel and Dickinson's kestrel and the three are sometimes placed in the subgenus Dissodectes.
- lisans
- cc-by-sa-3.0
- telif hakkı
- Wikipedia authors and editors
