Grey-headed Social Weaver, figure from Heuglin (1871)
Grey-headed Social Weaver, figure from Sharpe (1890)
Grey-headed Social Weaver, distribution, type locality circled
Introduction
The Grey-headed Social Weaver was formally described by Charles Lucien Bonaparte, a French biologist and ornithologist. Around 1849 Bonaparte began work on preparing a classification of all the birds in the world, visiting museums across Europe to study the collections. In 1850, he published the first volume of his Conspectus Generum Avium which included 3 weavers. Bonaparte studied the type specimen of the Grey-headed Social Weaver in the Paris Museum. He named it after the French collector Joseph-Pons d’Arnaud, a French engineer, hunter and explorer.Three expeditions were fitted out between 1839 and 1842 to search for the source of the White Nile. The second trip, with d’Arnaud as the scientific chief of the expedition, reached to around Juba. d’Arnaud collected a variety of birds, including the Grey-headed Social Weaver, which were sent to the Paris Museum.
The first illustration of a Grey-headed Social Weaver is by Heuglin (1871). The next illustration was a line drawing of the bird’s wing, published by Sharpe (1890). Reichenbach (1863) mentioned the species, and provided an English name, but did not illustrate it.
Scientific citation
Nigrita arnaudi Bonaparte 1850 Consp. Gen. Av., 1, p.444 White Nile, Sudan.
Meaning of names
arnaudi – named after A. d’Arnaud, French explorer in the Sudan and Ethiopia.
First English name
Arnauds Nigrita (Reichenbach 1863).
Alternate names
Masai Grey-headed Social Weaver.
Collector
Joseph-Pons d’Arnaud.
Date collected
1839-1842.
Locality collected
Nil. albo = White Nile.
Type specimens
The type specimen is probably in the Paris Museum.
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 [173] – Discovery [56]: Grey-headed Social Weaver on 2015-10-07
1. Basic biology
Grey-headed Social Weaver, figure from wikipedia
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.
Grey-headed Social Weavers, foraging on ground
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.
Grey-headed Social Weaver nest
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.
The above is based on Weaver Wednesday, a weekly series about weaver species.
This species text first appeared as Weaver Wednesday [25]: Grey-headed Social Weaver on 2012-12-05
2. Breeding facts
Pair bond
Monogamous; sometimes co-operative breeder, e.g. 25-30% of nests at a Kenyan colony had helpers. Colonial
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
Breeding information based on Handbook of the Birds of the World, Vol. 15.