Tessitore sociale calotta nera

Identificazione

The black-capped weaver is 13 cm (5.1 in) long and weighs 18–24 g (0.63–0.85 oz). Adult birds have an extensive and well-delimited black cap that runs from the bill opening, across the crown to the back neck, and also covers the area around the eye and ear. The neck, mantle, wings and rump are evenly brown. The tail is blackish brown. The throat, sides of the neck, breast, belly and vent are white. A clearly visible narrow longitudinal black stripe runs along the middle of belly to the stomach. Some black feathers also mark the side of the breast, but these are often difficult to see as they may partially or completely be covered by the wings. The legs are a dark horn color. The bill is ivory-colored. The eyes are bright red.Young birds miss the black markings entirely, which instead are the same brownish shade as the mantle and wings. The bill of juveniles is horn-colored and the iris is dark brown.

Tassonomia

In 1884, the black-capped social weaver was first described by German East-Africa explorer Gustav Fischer and German ornithologist Anton Reichenow as Nigrita cabanisi, based on a specimen collected in 1883 by Fischer in the Pare Mountains. In 1903, Reichenow assigned the species to his newly erected genus Pseudonigrita, because he considered P. arnaudi and P. cabanisi related to weaverbirds (Ploceidae), while the other species Nigrita bicolor, N. canicapillus, N. fusconota and N. luteifrons are negrofinches assigned to the estrildid finches. In 1942, Hans von Boetticher was of the opinion that our species was different enough to assign it to its own genus, and made the new combination Somalita cabanisi. The species name cabanisi, honors Jean Cabanis, a German ornithologist. There are no subtaxa.<p>"Black-capped social weaver" has been designated the official name by the International Ornithological Committee (IOC). Other common names include Cabanis's social waxbill and black-headed sociable weaver.<p>Based on recent DNA-analysis (which did not include P. cabanisi), the genus Pseudonigrita belongs to the group of sparrow weavers (subfamily Plocepasserinae), and is most related to Philetairus socius. This clade is sister to Plocepasser. Provided that the sister relationship between the Pseudonigrita-species is correct, the following tree expresses current insights.

Nome scientifico

Pseudonigrita cabanisi

Autorità

(Fischer, GA & Reichenow, 1884)

Ordine

Passeriformi

Famiglia

Ploceidae

Genere

Pseudonigrita

Areale e habitat

Pseudonigrita cabanisi occurs in central and southern Ethiopia, much of Kenya, a patch of Somalia towards the tripoint with Ethiopia and Kenya, and in northern Tanzania. The black-capped social weaver prefers semi-arid savannas dominated by acacias and other thorny bushes.

Migrazione

Resident species

Comportamento

The black-capped social weaver is monogamous and breeds in colonies. It feeds primarily on grass seeds, but also takes juicy vegetation to get enough water, and insects, particularly to feed the nestlings.<p>Favoured nesting trees include Acacia-species, Delonix and Euphorbia, and the roofed nests that are constructed by both male and female, are attached from thin, hanging branches, and are made of many straight grass straws. Nests have two downward-facing entrances, one of which is closed as soon as the eggs are laid until the moment the youngsters fledge. A clutch is made of two to four eggs of 19 mm (0.75 in) long and 14 mm (0.55 in) in diameter, white or pinkish in color, with brown or violet markings.

Conservazione

Tendenza della popolazione

stable