Black-capped Social Weaver Pseudonigrita cabanisi

Weaver species list / RELATED SPECIES: Black-capped Social Weaver / Grey-headed Social Weaver / Sociable Weaver

IUCN: Least concern Discovery: 079

Categories: cooperative, acacias, Pseudonigrita+Philetairus

Discovery

Black-capped Social Weaver figure from Shelley (1888)

 

Black-capped Social Weaver distribution, type locality circled

 

Introduction

The Black-capped Social Weaver was formally described jointly by Gustav A Fischer and Anton Reichenow, the latter being a German ornithologist and herpetologist.The Black-capped Social Weaver was collected by Gustav A Fischer, a German African explorer. He collected a large number of birds, including new species, in East Africa.

Fischer settled as a physician in Zanzibar in 1876, from where he undertook expeditions to Tanzania and Kenya. His third trip started in late 1882 at Pangani on the Tanzanian coast and he followed the Pangani River upstream. When he reached the Pare Mountains in March 1883, he collected the type specimen of the Black-capped Social Weaver. He continued to Kilimanjaro and appears to have collected another specimen in the same area on his return. Fischer saw the Black-capped Social Weaver in small groups in acacia bushes and he also found small colonies of nests.

The first illustration of the Black-capped Social Weaver was of the type, published by Shelley (1888). The second illustration for the species was a line drawing many decades later, in Mackworth (1955).

Scientific citation

Nigrita cabanisi Fischer & Reichenow 1884, Journ. f. Orn., 32, p.54, Plains by Pare Mts.

Meaning of names

cabanisi, After Jean Louis Cabanis (1816-1906) German ornithologist and author.

First English name

Cabanis’s Social-Waxbill (Shelley 1905).

Alternate names

Black-headed Sociable Weaver.

Collector

Gustav A Fischer.

Date collected

March and July 1883.

Locality collected

The plains between the Pangani River and Pare Mountains.

Type specimens

There are at least 2 types, one each in Berlin and Hamburg.

The above is based on Weaver Wednesday 2, a weekly series about the discovery of each weaver species.
This species text first appeared as Weaver Wednesday [196] – Discovery [79]: Black-capped Social Weaver on 2016-03-16

1. Basic biology


Adult

Identification. Black-capped Social Weaver is light brown above, with a black cap and a black tail, white below, white bill and red eyes. The sexes are alike. The juvenile differs from the juvenile Grey-headed Social Weaver in having whitish underparts, a dark brown crown, and having a longer tail that is dark without a pale tip.

Distribution. The Black-capped Social Weaver is found through southern Ethiopia, Somalia, Kenya and northern Tanzania. There are no recognised subspecies.

Habitat. The Black-capped Social Weaver is very localized in dry thornveld, generally below 1300 m. It is sometimes found with Grey-headed Social Weavers, and also with Speckle-fronted Weavers.

Food. The Black-capped Social Weaver forages on the ground, feeding mainly on seeds, and sometimes insects, including grasshoppers. Non-breeding flocks may be nomadic.

phown 9618
Black-capped Social Weaver nests

Breeding. The Black-capped Social Weaver is monogamous and colonial, with 7-61 nests in a colony. The nest is bulky, built of thin, dry grass stems and not lined. The protruding ends of the grass stems make it look untidy; sometimes several nests are so close that they merge. Roosting nests have two entrances, and one is closed for breeding nests. Both sexes add material throughout the year. One nest weighed 211 g, and contained about 9300 grass stems. Nests are often at the end of slender branches, in colonies on isolated acacia trees at about 2 m height.

The eggs (clutch 2-4) are white or pinkish, with brown and violet markings. lt is not known if both sexes incubate (as is the case in the Grey-headed Social Weaver). The Black-capped Social Weaver is a cooperative breeder and both parents, and some helpers, feed the young.

The above is based on Weaver Wednesday, a weekly series about weaver species.
This species text first appeared as Weaver Wednesday [6]: Black-capped Social Weaver on 2012-07-25

2. Breeding facts

Pair bond
Monogamous; thought likely to be co-operative breeder. Colonial

Breeding season
Feb-May; also Dec-Jan and Aug-Sept in Kenya

Nest site
placed c. 2 m above gromd in tree such as Delonix, Acacia mellifera, Acacia tortilis or tree euphorbia (Euphotbia), often near end of pendant branch, adjacent nests sometimes merging into apparent compound structure

Nest building
both sexes add material throughout year

Colony size
up to 60 nests in adjoining trees

Clutch size
2-4

Egg colour
white or pinkish, with brown and violet markings

Egg size
size 19 x 14 mm

Incubation
in captivity, young fed by breeding pair and additional adult

Chicks and nestling period
No information

Breeding information based on Handbook of the Birds of the World, Vol. 15.

3. Photos of Weaver Nests


Vm 28572
Vm 9892
Vm 9618
Vm 5112
Vm 2475
Vm 2028

Thumb-nails of most recent PHOWN records