Weaver species

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Dark-backed Weaver Ploceus bicolor

IUCN: Least concern     Discovery: 027

Categories: long tube, fruit, gum, nectar, Nest use, palm,
News items about species

Discovery

Dark-backed Weaver
Dark-backed Weaver,
figure from Jardine 1836
William Jardine,
figure from wikipedia
Dark-backed Weaver map
Dark-backed Weaver
distribution, type locality circled

Introduction

The Dark-backed Weaver was formally described by Louis Jean Pierre Vieillot, a French ornithologist. Vieillot already described it under a different name in 1818, but the name was not valid, and at first he thought it came from America. In 1819 he gave the valid name and noted that the specimen came from Senegal, but the Dark-backed Weaver does not occur west of Cameroon as was thought by early authors. Shelley 1887 first realised that the actual type specimen in Paris fitted birds from eastern South Africa, and later this was further restricted to the Eastern Cape.

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

Ploceus bicolor Vieillot 1819 Nouv. Dict. Hist. Nat., nouv. ed., 34:127 Senegal, errore = S Africa, vide Hartert 1907a. Restricted to Zuurberg, Addo, E Cape by Roberts 1931.

Meaning of names

bicolor Latin: bicoloured, two coloured (bi-, twice, double; color, colour).

First English name

Yellow-bodied Loret (Jardine 1836).

Alternate names

Black-backed Weaver, Forest Weaver, Grey-backed Weaver, Hinge Bird, Solitary Weaver-bird, Spot-headed Weaver.

Collector

Le Vaillant.

Date collected

1782, when Le Vaillant was in the Eastern Cape.

Locality collected

Eastern Cape, around Zuurberg.

Type specimens

Type specimen may be in the Royal Scottish 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 [144] - Discovery [27]: Dark-backed Weaver on 2015-03-18

1. Basic biology

Dark-backed Weaver
Dark-backed Weaver,
adult, nominate race
Dark-backed Weaver
Dark-backed Weaver,
juv with adult

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).

Dark-backed Weaver map

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.

Dark-backed Weaver
Dark-backed Weaver courtship

P. b. kersteni in S Somalia, coastal Kenya, E Tanzania south to Rufiji River, and Zanzibar Island (see orange on map). The upperparts are entirely black.
P. b. stictifrons, coastal Tanzania from Kilwa southwards, S Malawi, E Zimbabwe, Mozambique to northern KwaZulu-Natal in South Africa (see red on map). The upperparts are greyer and more olivaceous than other races, and the forehead feathers are tipped whitish.

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.

Dark-backed Weaver
Dark-backed Weaver adult in nest

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.

The above is based on Weaver Wednesday, a weekly series about weaver species.
This species text first appeared as Weaver Wednesday [35]: Dark-backed Weaver on 2013-02-13

2. Breeding facts

Pair bond
Monogamous, pair-bond lasting for several years
Breeding season
Nov-Dec on Bioko, Dec-Jan in Cameroon; in DRCongo, Feb-May and Sept-Dec in S and Jan-Feb in Itombwe; Aug-Sept in Somalia; Apr and Aug in Kenya (but Mar-May and Jul-Aug at Kakamega Forest); Dec-Jan in Tanzania; Aug, Oct-Nov and Feb in Angola, Sept-Dec in Zambia, Oct-Mar in Malawi, Sept-Feb in Zimbabwe, Sept-Dec in Mozambique, and Oct-Jan in South Africa
Nest site
supended 2.5-15 m (most often 4.5-6 m) above ground from tip of branch or creeper, often in thorny tree, on Zanzibar also suspended from telephone line
Nest building
Both partners may build nest, usually one member of pair, presumed to be male, does most building while partner perches nearby
Colony size
Solitary nester; pair usually in same area each year, so that two or three nests may be found close together
Clutch size
2-4 eggs (average 3 in South Africa)
Egg colour
pure white, pale blue, pink or greenish-white, sparsely spotted with brown, red and lilac
Egg size
average size of 54 eggs 22.7 x 15.4 mm (South Africa)
Incubation
in captivity, incubation by both sexes, estimated period 15-17 days
Chicks and nestling period
chicks fed by both male and female, nestling period 22 days; fledglings fed occasionally until 6 weeks old

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

3. Photos of Weaver Nests


Vm 24437

Vm 23370

Vm 21196

Vm 21195

Vm 20280

Vm 19719

Thumb-nails of most recent PHOWN records - click on one to see its full record
See all PHOWN records for this species here.

PHOWN (Photos of Weaver Nests) provides valuable info on breeding distribution and colony sizes of weavers.
You can contribute by registering and submitting photos at Virtual Museum webpage.

4. Breeding distribution

Google map showing distribution (For species with small ranges you need to zoom in at the correct area to see the range):
yellow blob - range of weaver species; read more about this here.
- PHOWN records with photos
- PHOWN records with no photos (Nest Record Cards, other records)
- Birdpix records
- comments on out of range records, or interesting records
- type locality
CLICK on the marker on the map to see individual record details.

5. Range changes

map
Dark-backed Weaver, Range-change map between SABAP1 (1987-1991) and SABAP2 (2007-current).
Red, orange and yellow = cells with very large, large, and small relative decreases
Blue, dark green and light green = cells with very large, large and small relative increases.
Cells = quarter-degree grid cells; Only cells with at least 4 checklists in both SABAP1&2 shown. All cells had this species recorded in SABAP1 or in SABAP2 or in both (more about interpretation at Biodiversity Observations 7.62: 1-13).

Dark-backed Weaver
Dark-backed Weaver,
figure from Birdpix

Range changes in SA

Range change summary
More 4 lists 30 lists
increases n % n %
Decrease 64 34 35 27
Tiny change 50 27 38 29
Increase 77 41 57 44
Total 191 102 130 100
In South Africa the Dark-backed Weaver has more grid cells with increases in reporting rate than cells showing decreases, between SABAP1 (1987-1991) and SABAP2 (2007-), although this is reversed when using 30 checklists for the analysis. The Dark-backed Weaver is still regular in many areas but habitat loss and fragmentation of natural forest may affect the overall population of this species. The points below match the points on the map above.

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

Uganda: 3 seen, first record at Mt Elgon for 100 years (Demey 2011b).
Zimbabwe: range expansion upstream along Zambesi River (Rushforth 2003a).
Zimbabwe: range expansion - Lake Manyame, Harare (Baker 2009a).

The above is based on Weaver Wednesday 3, a weekly series about range changes in South African weaver species.
This species text first appeared as Weaver Wednesday 3 [242] - Range changes [5]: Dark-backed Weaver on 2017-02-01