Introduction

The Dark-backed Weaver was first collected by Francois Le Vaillant, who travelled in South Africa in 1781-84, and reached the Eastern Cape in 1782, where the Dark-backed Weaver occurs. When Le Vaillant returned to Europe, most of his specimens where sold or given to Coenraad Jacob Temminck, who had sponsored Le Vaillant's travels. Temminck produced a catalogue of these birds in 1807 and briefly described the Dark-backed Weaver, without providing a scientific name, but calling it "Le verdier a ventre jaune" (Greenfinch with a yellow belly). He noted that it came from "Africa, Cape of Good Hope" (which includes the Eastern Cape).

Vieillot based many of his descriptions on the work of Temminck 1807, but included a scientific name.

Later Jacques Pucheran (1854), a French zoologist, noted that the Dark-backed Weaver type had been in the collection of Louis Dufresne, a French ornithologist and taxidermist at the natural history museum in Paris. Either the type had been transferred or Le Vaillant had more than 1 specimen, and kept one for the Paris museum, since Le Vaillant was friends with Dufresne.

The collection of Louis Dufresne was sold to the University of Edinburgh in 1819 (and later moved to the Royal Scottish Museum). The first illustration of this species to be published, was by William Jardine in 1836, a Scottish naturalist, who had access to the Scottish collection. In addition to the Dufresne specimen (Jardine did not know the apparent source as Dufresne), Jardine also had other specimens from Dr Andrew Smith.

Scientific citation

Meaning of names

First English name

Alternate names

Collector

Date collected

Locality collected

Type specimens

Identification. The Dark-backed Weaver Ploceus bicolor is bright yellow below and dark above, the throat is solid black or mottled black and yellow. The sexes are alike (photo left). Juveniles (photo right) are duller than adults, have a mottled throat, and pale bill. The wing edges are dark (unlike Clarke's Weaver).

Distribution. Seven subspecies of the Dark-backed Weaver are recognised, although many more have been proposed (see map left, based on Birds of Africa):
P. b. bicolor in E Cape to KwaZulu-Natal in South Africa (see yellow on map).
P. b. tephronotus in SE Nigeria, Cameroon, Bioko Island, Gabon and western Congo (see dark green on map). The crown and nape are brownish black, mantle slate-grey, and the throat is brownish black flecked with grey.
P. b. amaurocephalus in Angola and southern DRC (see blue on map). The crown and cheeks are brownish black, mantle and throat grey.
P. b. mentalis in South Sudan, NE DRC, Uganda, and western Kenya (see grey on map). The back is dark grey, crown and cheeks black, throat black or sometimes yellow and black.
P. b. kigomaensis in Rwanda, Burundi, east and SE DRC, Zambia, extreme SW Tanzania (see light green on map). The throat feathers are tipped with yellow but throat is more blackish than amaurocephalus.

Habitat. The Dark-backed Weaver inhabits forested areas, including riverine and gallery forests in open country, and second-growth forest regenerating after shifting cultivation, coffee forests, denser patches in dry baobab woodland, and in South Africa dry Valley Bushveld. It joins mixed-species flocks of insectivorous birds.

Food. Food items are mostly arthropods, including grasshoppers, beetles, caterpillars, bugs, flies and spiders. Other food items are berries, fruit, and nectar. This species forages in the tree canopy and at the leafy ends of branches.

Breeding. The Dark-backed Weaver is a monogamous, solitary nester, with the pair-bond lasting for several years. The nest is retort-shaped. The entrance is extended into a spout that is usually <30cm long but may be up to 60 cm. The nest looks rough because it is made of stiff materials such as thin vines and creepers. A pair usually nests in the same area each year, so there may be 2-3 nests close together. One nest took 7 days to complete, and another took 9 days. Although nests are often high, and at the end of twigs, snakes do reach them and take young.

Other. The longevity record for Dark-backed Weaver is over 5 years in the wild, but can be expected to be much more (see news item).

The song of the Dark-backed Weaver is often a duet, with the male and female singing the same elements in a nearly simultaneous sequence, after some introductory notes which show increasing synchrony. There are local dialects in this song which appear to remain stable over many years. There are large-scale differences in song between geographically separated populations. The young apparently learn the song from their parents and other adults, and the song type stabilizes within the first two years.

Range changes in SA

Areas with very large increases include:
1. range expansion at northern end of its South African range, i.e. in Mpumalanga
2. range expansion at southern end of its range, i.e. around the Eastern Cape/Western Cape border

Large decreases appear to have occurred:
3. low reporting rate and shows decreases in southern KwaZulul-Natal.

Range changes elsewhere