Shikra

Identificazione

The shikra is a small raptor (26–30 cm long) and like most other Accipiter hawks, this species has short rounded wings and a narrow and somewhat long tail. Adults are whitish on the underside with fine rufous bars while the upperparts are grey. The lower belly is less barred and the thighs are whitish. Males have a red iris while the females have a less red (yellowish orange) iris and brownish upperparts apart from heavier barring on the underparts. The females are slightly larger. The mesial stripe on the throat is dark but narrow. In flight the male seen from below shows a light wing lining (underwing coverts) and has blackish wing tips. When seen from above the tail bands are faintly marked on the lateral tail feathers and not as strongly marked as in the Eurasian sparrowhawk. The central tail feathers are unbanded and only have a dark terminal band. Juveniles have dark streaks and spots on the upper breast and the wing is narrowly barred while the tail has dark but narrow bands. A post juvenile transitional plumage is found with very strong barring on the contour feathers of the underside. The call is pee-wee, the first note being higher and the second being longer. In flight the calls are shorter and sharper kik-ki ... kik-ki. The Chinese sparrowhawk is somewhat similar in appearance but has swollen bright orange ceres and yellow legs with the wing tips entirely black.<p>Subspecies cenchroides is larger and paler and found in Turkestan, Afghanistan and eastern Iran. The Indian population dussumieri is resident on the plains and lower hills (up to 1400 m in the Himalayas). The nominate form is found in Sri Lanka and has somewhat darker grey upperparts. The Burmese shikra A. b. poliopsis may represent a distinct species. The population on the island of Car Nicobar, earlier treated as a subspecies butleri and that on Katchal Island, obsoletus are now treated as a sub-species within a full species, the Nicobar sparrowhawk (Accipiter butleri). The west African population A. b. sphenurus is migratory while the southern African A. b. polyzonoides is more nomadic in its movements. In Asia only A. b. cenchroides is migratory.

Tassonomia

The shikra was formally described in 1788/1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the eagles, hawks and relatives in the genus Falco and coined the binomial name Falco badius. Gmelin description was based on the "brown hawk" from Ceylon that had been described and illustrated in 1776 by the English naturalist Peter Brown. The shikra is now one of 49 species placed in the genus Accipiter that was introduced in 1760 by the French zoologist Mathurin Jacques Brisson. The genus name is Latin for "hawk", from accipere, "to grasp". The specific epithet badius is Latin for "chestnut-coloured" or "brown".<p>Six subspecies are recognised:

Nome scientifico

Tachyspiza badia

Autorità

(Gmelin, JF, 1788)

Ordine

Accipitriformi

Famiglia

Accipitridae

Genere

Tachyspiza

Areale e habitat

Migrazione

Complete migrants

Comportamento

The shikra is found in a range of habitats including forests, farmland and urban areas. They are usually seen singly or in pairs. The flight is typical with flaps and glides. During the breeding season pairs will soar on thermals and stoop at each other. Their flight usually draws alarms among smaller birds and squirrels. They feed on rodents (including Meriones hurrianae), squirrels, small birds, small reptiles (mainly lizards but sometimes small snakes) and insects. Small birds usually dive through foliage to avoid a shikra and a Small Blue Kingfisher has been observed diving into water to escape. Babblers have been observed to rally together to drive away a shikra. They will descend to the ground to feast on emerging winged termites, hunt at dusk for small bats (such as Cynopterus sphinx) and in rare instances they may even resort to feed on carrion. In one instance a male was found feeding on a dead chick at the nest. Their calls are mimicked by drongos and this behaviour is thought to aid in stealing food by alarming other birds that the drongos associate with.<p>The breeding season in India is in summer from March to June. The nest is a platform similar to that of crows lined with grass. Both sexes help build the nest, twigs being carried in their feet. Like crows, they may also make use of metal wires. The usual clutch is 3 to 4 eggs (when eggs are removed they lay replacements and one observer noted that they could lay as many as 7 in a season) which are pale bluish grey stippled on the broad end in black. The incubation period is 18 to 21 days.

Conservazione

Tendenza della popolazione

stable