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 [142] – Discovery [25]: Black-necked Weaver on 2015-03-04
1. Basic biology
Identification. The Black-necked Weaver Ploceus nigricollis is similar to the Spectacled Weaver, having a golden head with a narrow black mask through the eye, and a black bib in the male. Birds from Cameroon to Kenya are easily distinguished from the Spectacled Weaver by black upperparts, wings and tail in both sexes; the female and juvenile have a diagnostic yellow line between the black crown and mask. Birds in West Africa have green upperparts and differ from Spectacled Weavers in having a green (not yellow) crown, the male has a heavy chestnut wash around the black part, and the female has a yellow line between the crown and mask and a brown eye.
Distribution. The Black-necked Weaver is found from West to eastern Africa. Three subspecies are recognised (see map above, based on Birds of Africa): P. n. nigricollis, black-backed, in central Africa (see red on map). P. n. brachypterus, green-backed, in West Africa, including Bioko Island (see green on map). Birds from Bioko may be an additional race (po) having a longer and heavier bill, but further study is needed. P. n. melanoxanthus, black-backed, in East Africa (see blue on map). The male resembles the nominate subspecies but the forehead and crown are golden yellow.
Habitat. The Black-necked Weaver inhabits woodland, ranging from savanna to gallery forest, forest clearings and edges, gardens, oil palm, cocoa and coffee plantations, and mangroves, and occasionally in eucalypt plantations. Pairs remain together all year. It is not usually gregarious but small groups may forage together during the dry season, and may roost in groups.
Food. The Black-necked Weaver is mainly insectivorous, feeding on grasshoppers, caterpillars, beetles, ants, bugs, termite and ant alates. It also feeds on seeds, spiders, berries, fruit and nectar. In one study in Ivory Coast, diet was estimated as 60% arthropods, 20% fruit and 10% seeds. It sometimes joins mixed-species flocks of insectivores around clearings, gleaning the vegetation for insects. It usually feeds within 2 m of the ground, but may feed in the canopy.
Black-necked Weaver nest
Breeding. The Black-necked Weaver is solitary and monogamous, probably having a permanent pair bond, but polygyny has been recorded. The male defends the immediate vicinity of the nest. There are usually solitary nests or, where several nests are together, only one is occupied. One colony had 30 pairs in oil palm near Libreville, Gabon.
The nest is retort-shaped with the entrance tunnel short or up to 20 cm long but narrower than the tunnel of the Spectacled Weaver. The nest is woven of grass, or in more forested areas, vine stems or tendrils of creepers. It is not tightly woven and often unlined, so that the eggs are visible from outside, but nests are usually well hidden (in contrast to the more exposed nests of Spectacled Weavers).
The nest is usually built in the centre of thick trees but in Uganda may be attached to elephant grass. On Bioko nests in coconut palms are built near wasp nests. Two eggs are laid, and they are blue to whitish, with fine red speckles.Old nests of the Black-necked Weaver may be used for breeding by Dusky-blue Flycatchers Muscicapa comitata and occasionally by Bronze Mannikins Spermestes cucullata.
The above is based on Weaver Wednesday, a weekly series about weaver species.
This species text first appeared as Weaver Wednesday [65]: Black-necked Weaver on 2013-09-11
2. Breeding facts
Pair bond
Monogamous, probably with long-term pair-bond; occasionally polygynous, e.g. at two sites in Kenya male acquired two females
Breeding season
Jul-Nov in Senegambia, Sept-Oct in Liberia, Jan-Mar in Ghana, Jul in Burkina Faso, Jun-Sept in Nigeria, mainly Mar-Apr and Aug-Sept in Cameroon, in most months except main dry season (most breeding Nov-Apr) in Gabon, Nov in PRCongo; in DRCongo, Feb-Mar and Jun-Oct in Kivu, Mar-Oct in NE and Nov-Dec in Itombwe; in most months (peaks Apr-May and Sept) in Uganda, Jan-Jul (mainly Mar-May) in Kenya, and Sept-Oct and Jan in Rwanda
Nest site
suspended from tree in savanna steppe or attached to elephant grass in E Africa, in W Africa up to 2 m above ground in low tree, even in villages in Cameroon; on Bioko, in oil palm close to nest of the wasp Polibioides tabida
Nest building
built by male, female sometimes contributing
Colony size
Old reports of colonial nesting in W Africa, and colonies of up to six nests noted in Liberia, also group of 30 nests in oil palms in Gabon (nesting on fringes of mixed colonies of P. cucullatus and P. nigerrimus may account for some of these observations), and two pairs in Gabon nested within 5 m of each other; elsewhere a solitary nester, or, where several nests present only one occupied (single male may build up to four nests at a site)
Clutch size
usually 2 eggs
Egg colour
blue to whitish with fine red speckles
Egg size
average size of 29 eggs 21 x 14 mm (Cameroon)
Incubation
incubation at one nest reported as done by both male and female, at another by female only; no information on duration of incubation period
Chicks and nestling period
chicks fed by both sexes; no information on duration of nestling period
Breeding information based on Handbook of the Birds of the World, Vol. 15.