Grey-headed Social Weaver Pseudonigrita arnaudi

Identification. The Grey-headed Social Weaver is a brownish bird with a conspicuous pale grey crown, white eye-ring and pale-tipped tail; the sexes are similar (photo above). The Grey-headed Social Weaver is similar to the only other species in its genus, the Black-capped Social Weaver. The two species can occur together, although the Grey-headed usually prefers wetter areas than the Black-capped.

Distribution. The Grey-headed Social Weaver is found in eastern Africa. Two subspecies are currently recognised (see map above, based on Birds of Africa):
P. a. arnaudi in SW Sudan, south to NW Tanzania (see red on map right).
P. a. dorsalis in north, central and eastern Tanzania (see blue on map right). The mantle is grey instead of brown.

Habitat. The Grey-headed Social Weaver is found in bush and acacia woodland.

Food. The Grey-headed Social Weaver feeds mostly on the ground, eating grass seeds and insects, the latter including grasshoppers, beetles, termites and caterpillars. They feed their young on soft green grass seeds and insects. They drink regularly.

Breeding. The Grey-headed Social Weaver is a colonial, monogamous, co-operative breeder. Several groups of 2-10 birds occupy a colony, each group having 2-8 nests, with up to 157 nests, sometimes touching, in a single tree. Sub-adult helpers may assist in feeding young. Breeding depends on rainfall and at some colonies, eggs are laid in all months of the year.

The nest (photo) is built by both sexes and is a large, compact grass structure firmly attached to thin branches. The nest is symmetrical, with 2 openings below in roosting nests, but one entrance is closed when eggs are laid. The nest is made of straight grass stems, and placed like thatch around a central cavity. Birds constantly add to and modify the nest.

Incubation is by both sexes. Pairs with helpers raise more young than pairs without helpers.

Old nests are used by Cut-throat Finches Amadina fasciata, while Chestnut Sparrows Passer eminibey actively take over new nests.

Breeding season
in all months; peak Aug-Dec in Sudan and Mar-May in Ethiopia and E Africa

Nest site
attached to thin branches, often of ant-gall acacia (Acacia drepanolobium), sometimes in other acacias (A. mellifera, A. senegala, A. tortilis)

Nest building
Nest built by both sexes

Colony size
up to 157 nests, some in fused masses, in single tree

Clutch size
3-4

Egg colour
greenish or blue-white, often plain white with fine olive or black specks concentrated at thick end, sometimes heavily blotched olive-brown and ash-grey

Egg size
average size of six eggs 19 x 14 mm (Kenya)

Incubation
incubation by both parents (in captivity, 70% of work by female), period 13-14 days

Chicks and nestling period
young fed by both parents and by helpers,latter predominantly males (which contribute most when food demand by chicks greatest), nestling period 20 days