Cape Weaver Ploceus capensis

Weaver species list / RELATED SPECIES: Bocage’s Weaver / Cape Weaver / Chestnut Weaver / Fox’s Weaver / Heuglin’s Masked Weaver / Speke’s Weaver

IUCN: Least concern Discovery: 006

Categories: golden, , acacias, fruit, waterbirds, gum, Linnaeus, Gymnogene, nectar, pest, Nest use, double nests, blue eggs, palm

Discovery

Cape Weaver male, figure by Martinet (in Daubenton 1783)

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 [123] – Discovery [6]: Cape Weaver on 2014-10-22

1. Basic biology

Identification. The Cape Weaver Ploceus capensis is a large weaver, with a long bill. The adult male in breeding plumage is bright yellow with varying amounts of orange-brown on the face, a black bill, and a pale eye (photo at top of page). The female is olive, with a yellow throat and belly, brown eye, and pale horn bill. Adult females usually have brown eyes, but 19% have pale eyes in summer and thus eye colour alone cannot be used to sex this species (read more at here) (photo below). The male is in non-breeding plumage for a relatively short time when it resembles the female but is yellower below, and retains the pale eye. The juvenile is dull, with a yellowish belly.

Distribution. No subspecies of the Cape Weaver are recognised and it is a near endemic to South Africa (see map above, based on The Atlas of Southern African Birds and on SABAP2). The stronghold of the species is in the Western Cape. Currently it seems to have decreased its range in some areas, particularly in the northern Free State and North-West Province (red grids on the map).

Habitat. The Cape Weaver inhabits open country with some trees and permanent water. In hot, drier regions it is restricted to montane areas. The Cape Weaver never occurs in forest.

This species is found in flocks, and it forms large roosts throughout the year, which may be shared with other weavers and species. In some areas they leave their breeding sites, and do not return until the following season. Anting has been recorded. Cape Weavers may bathe even in misty or rainy conditions.

Food. The Cape Weaver has a relatively long bill that is adapted to feeding on a wide variety of vegetable and animal matter. There is a long list of recorded food items, including various insects, spiders, seeds, nectar, and fruit. Females appear to have a more varied diet than males. They forage on the ground and may turn over small stones and dried cow-pats. They also search the bark of trees for insects, and hawk flying insects. Cape Weavers are generalist nectar-feeders that are now considered to be the major pollinators of aloes.

Breeding. The Cape Weaver is colonial and highly polygynous with up to 7 females per male. Males are strongly territorial within a colony, and males chase intruders off neighbouring territories. The nest (photo above from phown 1094) is built by the male. The nest is a bulky, kidney-shaped structure, with the entrance below and usually without an entrance tunnel. Males display from their nests to attract females. If a female accepts a nest, she lines it with fine grass. If a female does not accept a nest, she searches elsewhere and the male may eventually break it down to make space for a new nest.

Cape Weaver nests are mostly built in a variety of trees (n=725, PHOWN database), often exotics like gum, poplars, and willow trees, but also in indigenous trees like acacias. Nests are also built in reeds (n=140) and on man-made sites (n=9). Colonies may be large with up to 348 nests recorded, but the average colony size is around 20 nests.

Some interesting PHOWN records are: boomslang raiding colony phown 572 (photo above), colony in shopping mall phown 1260, and nests built on a building phown 1196. Cape Weavers also build their nests near nests of larger birds, like Hadedas or in heronries. Old nests may be used by Cape Sparrows Passer melanurus or African Dusky Flycatchers Muscicapa adusta.

The above is based on Weaver Wednesday, a weekly series about weaver species.
This species text first appeared as Weaver Wednesday [32]: Cape Weaver on 2013-01-23

2. Breeding facts

Pair bond
Polygynous, with up to seven females per male

Breeding season
Jul-Nov in winter-rainfall region of Western Cape (even Jun when high rainfall occurs early in season) and Aug-Feb (sometimes to Apr) in summer-rainfall region

Nest site
supported on each side by reeds or bulrushes (Typha), or suspended from tip of branch, occasionally on fence or telephone line; placed low in reeds, often less than 1 m above water, but in trees up to 10 m above ground

Nest building
woven by male, lined by female

Colony size
Highly territorial

Clutch size
2-5 eggs (mean 2.6 in Western Cape)

Egg colour
plain deep tuquoise-blue

Egg size
average size of 23 eggs 25 x 16.6 mm (South Africa)

Incubation
incubation by female, period 13-14 days

Chicks and nestling period
chicks fed by female, late in season sometimes also by male, and some males contribute as much as does female; nestling period 17 days

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