Corbin de Stresemann

Identification

The Stresemann's bushcrow is about 28 centimeters (11 in) long and weighs 130 grams (4.6 oz). The genders look similar and are not sexually dimorphic. Overall it is pale grey with a black tail and wings. The head, mantle, scapulars, back, rump, and uppertail coverts are all a pale grey. The feathers on the forehead, upper ear-coverts, and throat fade into white. The bright azure skin around the bushcrow's eye is featherless and can be inflated, narrowing the blackish-brown eye into a slit. The feathers behind the eye are capable of moving to reveal an oblong pink patch of skin. The bird's black beak decurves into a sharply pointed tip and is relatively small for a corvid. This beak is 33 to 39 millimeters (1.3 to 1.5 in) long. The feathers on the bird's chin are fine and can form a small tuft when erected. The bushcrow's breast and flanks are pale grey, fading into white on the rear flanks, belly, and undertail. On the wings, the lesser and median upper-wing coverts are grey, while the rest of the wing is a slightly glossy blue-black. Its blue-black tail is relatively long and square-ended. Its legs are black. When the plumage becomes worn, the upperparts appear to have a brownish tinge. The juvenile Stresemann's bushcrow is slightly duller than the adult, and the feathers of the body and upperwings are fringed with creamy-fawn. The facial skin, bill, and legs are also a dull grey.<p>The bushcrow is a very vocal species, particularly when foraging. Its main contact call has been described as a single metallic "kej". While flying, the species frequently calls out a nasal, rapid "kerr kerr kerr". While these are the most frequent vocalizations, several others are known. Allopreening adults utter a metallic "kaw, kaw, kaw". Foraging birds call out "how, how, how", a single, quiet "quak", and a soft, repeated "guw". While building its nest, the bushcrow is known to utter a low "keh" sound, and adults utter a deep "waw" while rubbing their bills together.

Taxonomie

Stresemann's bushcrow was formally described in 1938 by the Italian ornithologist Edgardo Moltoni. The species has been placed in several bird families since its description. It has long been considered a member of the crow family Corvidae; however, several atypical features, such as its lice being from the suborder Mallophaga, its bare facial skin being capable of movement, and the structure of its palate, have suggested that it may belong in another family. Some authors placed the species within the starling family Sturnidae due to the bushcrow's similarities in behavior and size with the wattled starling. Other authors have placed it in its own monotypic family, Zavattariornithidae. DNA-sequencing analysis supports its placement in the corvids, with its closest relatives being the ground jays, and the piapiac. It has been suggested that the bushcrow is a surviving relict ancestor to several of these relatives.<p>This species has numerous common names, including Stresemann's bushcrow, bush-crow, Ethiopian bushcrow, Abyssinian bushcrow, and Zavattariornis.<p>The genus name Zavattariornis commemorates Edoardo Zavattari, an Italian zoologist and explorer who served as the director of Rome University's Zoological Institute between 1935 and 1958. Its name commemorates Erwin Stresemann, a German ornithologist.

Nom scientifique

Zavattariornis stresemanni

Autorité

Moltoni, 1938

Ordre

Passériformes

Famille

Corvidés

Genre

Zavattariornis

Répartition et habitat

This species is endemic to central-southern Ethiopia. It lives in a small area circumscribed by the towns of Yabelo, Borena, Mega, and Arero in Sidamo Province, and settles in wildlife under protection within Yabelo Wildlife Sanctuary and Borana National Park. Its total range covers about 2,400 square kilometers (930 sq mi).<p>The Stresemann's bushcrow lives in flat savanna covered with mature acacia and Commiphora thornbushes. The bird prefers open short-grass savannas with scattered stands of these mature thornbushes. The soil must be deep and rich to support the bushcrow. It is most numerous when these stands are next to agricultural fields. For many years it was unknown why the species could be completely absent from areas of suitable habitat near seemingly identical but inhabited land. However recent research has revealed that the bird appears to inhabit an area with a very precise average temperature extreme, all of the seemingly suitable but uninhabited surrounding lands actually have a slightly higher average temperature that appears to prevent the birds from successfully colonizing. It is also not found near the scattered broadleaf woodland made up of Combretum and Terminalia. Its habitat is between 1,300 and 1,800 meters (4,300 and 5,900 ft) above sea level.

Migration

Espèce sédentaire

Comportement

Mode de migration: Espèce sédentaire.

Conservation

Tendance de la population: en déclin.

Tendance de la population

en déclin