Weaver species

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Red-billed Buffalo-Weaver Bubalornis niger

IUCN: Least concern     Discovery: 039

Categories: black, cooperative, long tail, acacias, fruit, gum, baobab, Gymnogene, nectar, Nest use, palm, Bubalornis+Dinemellia,
News items about species

Discovery

Red-billed Buffalo-Weaver
Red-billed Buffalo-Weaver
figure from Smith 1841
Red-billed Buffalo-Weaver
Red-billed Buffalo-Weaver,
figure from Reichenbach 1863
Red-billed Buffalo-Weaver map
Red-billed Buffalo-Weaver
distribution, type locality circled

Introduction

The Red-billed Buffalo-Weaver was collected and formally described by Andrew Smith, a Scottish surgeon, explorer, ethnologist and zoologist. Smith organised an expedition to the interior of South Africa and he travelled to near the Botswana border in 1834-35, collecting many new birds, reptiles, mammals and other taxa along the way.

Smith described the Red-billed Buffalo-Weaver from Kurrichane area. In Smith's Illustrations he expands on the locality given in the type description: 'It was not till after we had passed to the northward of the 25th degree of south latitude that we discovered this bird' (Smith 1841a). Sclater (1930) restricted the type-locality to Kurrichaine, a peak 20 km north of Zeerust. Clancey (1964) restricted it to Zeerust, a town that did not exist in Smith's day.

In Smith's diary (Kirby 1940), Smith's first and only reference to the species appears on 1 August 1835. Smith left Tolane on 28 July and followed the Great Marico River to Eerstepoort, which was reached on 8 August. Smith provides daily travel times, permitting an approximate locality to be calculated for 1 August as c.25 00'S, 26 23'E (Oschadleus 2007). This buffalo-weaver was not recorded at Zeerust during the atlas (Harrison et al. 1997), but was recorded rather frequently along the Marico River. Thus the type locality is best described as Great Marico River in North West Province.

The first illustration of a Red-billed Buffalo-Weaver was published by Andrew Smith in 1841 in his well known work, Illustrations of the Zoology of South Africa, being painted by George Henry Ford. The next illustration was published in Reichenbach (1863), being of a male in a similar pose to Ford's illustration.

Scientific citation

Bubalornis niger Smith 1836; Rep. Exped. Centr. Africa, p.52; 'Country about Kurrichane'.

Meaning of names

niger - Latin: niger, black, shining black (cf. ater, matt black, dead black).

First English name

buffalo-bird (Livingstone 1857).

Alternate names

Black Buffalo Weaver, buffalo-bird, Coral-billed Weaver, Northern Red-billed Buffalo-Weaver, South African Buffalo Weaver, The millet eating Alectornis.

Collector

Andrew Smith.

Date collected

1 August 1835.

Locality collected

Kurrichane = Great Marico River, North West Province, South Africa.

Type specimens

One type specimen is known: Edinburgh NMSZ 1843.028.001, though there may be more.

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 [156] - Discovery [39]: Red-billed Buffalo-Weaver on 2015-06-10

1. Basic biology

Red-billed Buffalo-Weaver
Red-billed Buffalo-Weaver adult male,
showing phalloid organ on the belly

Identification. The Red-billed Buffalo-Weaver is a large, black or brownish weaver. It differs from the White-billed Buffalo-Weaver in bill colour, being red in the male Red-billed Buffalo-Weaver, orange-yellow to horn-brown in the female and immature. The male Red-billed Buffalo-Weaver is black and the female is dark brown with the underparts mottled brown and white. Immatures are similar to the female but paler brown above, with grey cheeks.

Buffalo-Weavers are unique among weavers (and most birds) in that they have a solid phalloid organ on the belly in front of the cloaca. The organ is larger in males than females - the function of this organ during their prolonged copulation is not entirely certain.

Buffalo-Weavers do not normally associate with buffalo but by a twist of chance, Andrew Smith (who first described the Red-billed Buffalo-Weaver) first saw this species associating with buffalo in North West Province, South Africa.

Distribution. The Red-billed Buffalo-Weaver is found in southern and East Africa. There is a small zone of overlap in East Africa with the White-billed Buffalo-Weaver. The Red-billed Buffalo-Weaver is divided into two subspecies:
B. niger niger found in southern Africa (red on the map).
B. niger intermedius found in East Africa (green on map). This race has narrow white bases to the primary feathers, ie. the white wing panel is smaller than in the nominate race; the bill colour of the male may be variable, though is usually red.

There have probably not been any major range changes for this species in historical times, but it is probably more common where it can choose man-made nest sites within its range.

Habitat. The Red-billed Buffalo-Weaver inhabits savanna, dry thornveld and woodland, including dry mopane and mixed acacia-baobab woodland. It needs large trees for nesting, which may account for its patchy distribution in many areas.

Food. The Red-billed Buffalo-Weaver feeds mainly on insects, particularly grasshoppers and caterpillars, but also takes seeds and fruit. The young are fed with insects only. It forages primarily on the ground where it runs or hops. It may join mixed flocks of other species to forage.

Breeding. This species is usually polygynous, with one male and several females occupying a nest.

Red-billed Buffalo-Weaver
Cross-section of Red-billed
Buffalo-Weaver nest

Red-billed Buffalo-Weaver
Red-billed Buffalo-Weaver nest
on radio mast, PHOWN 2495
Sometimes two males form a coalition to defend a group of nests and both will help feed the chicks in the different chambers. The male usually builds the nest, collecting twigs up to 1 km away. The nest is an untidy mass of thorny twigs, with several nest chambers inside as illustrated in the photo (left) of a sign board at the Skukuza nursery in Kruger National Park, South Africa.

Nests are built on large trees, often baobabs. Nests are also built on man-made structures, including windmills and electricity pylons. One particularly unusual site that has not been documented in the literature is a radio mast - see photo (right).

The female incubates the eggs. Nests may be infested with mites and other invertebrates. Raptors sometimes nest on top of buffalo-weaver nests and a variety of smaller birds, especially Red-headed Finches, may take over a nest chamber, eg. PHOWN 196.

The above is based on Weaver Wednesday, a weekly series about weaver species.
This species text first appeared as Weaver Wednesday [5]: Red-billed Buffalo-Weaver on 2012-07-18

2. Breeding facts

Pair bond
polygyny, sometimes co-operative polygynandry
Breeding season
mainly Mar-Jun in E Africa; Sept-Apr in S Africa; scattered records in other months; may be double-brooded
Nest site
3-12m above ground in tall tree such as baobab, leadwood (Combretum imberbe), acacia, marula (Sclerocarya birrea) or mopane, even in base of nest of Yellow-billed Stork (Mycteria ibis) in Zambia; sometimes near homestead, or on man-made structure such as windmill or pylon
Nest building
Nest built by male, lined by both sexes with fresh green vegetation
Colony size
up to 13 nest-chambers
Clutch size
2-4 eggs
Egg colour
white, heavily spotted with sepia and grey, or blue-green with olive-green and ashy markings
Egg size
average size 28.3 x 19.9 mm (South Africa)
Incubation
incubation from first egg (in captivity), by female alone, period 11-14 days
Chicks and nestling period
chicks fed by female, very rarely by male, nestling period 20-23 days

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

3. Photos of Weaver Nests


Vm 31111

Vm 31095

Vm 31055

Vm 30996

Vm 30544

Vm 30380

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

Read more in Biodiversity Observations.
map
Red-billed Buffalo-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).

Range changes in SA

weaver
Red-billed Buffalo-Weaver,
figure from Birdpix

Range change summary
More 4 lists 30 lists
decreases n % n %
Decrease 125 48 47 49
Tiny change 39 15 17 17
Increase 99 37 32 34
Total 263 100 96 100
In South Africa the Red-billed Buffalo-Weaver has more grid cells with decreases in reporting rate than cells showing increases, between SABAP1 (1987-1991) and SABAP2 (2007-). The points below match the points on the map above.

1. Range expansion westwards from Kathu to Askham
The blue grid cells on the western edge represents a large westward range expansion (between SABAP1 and SABAP2) from Kathu and the Botswana border west to Van Zylsrus and as far as Askham, a distance of about 100km. There is also a PHOWN record from Askham based on the 2010 Google Streetview, indicating nest building and possible breeding.

2. Range extinction in the Free State
The two red cells in the Free State represent the isolated population that was present around Bloemhof Dam, Free State. Birds were first seen in 1981 and nests were seen in 1986. The last published report appears to be from May 2000 and the species no longer occurs here (SABAP2).

3. Range stable along the 26S line of latitude
In South Africa it is found mostly north of 26S (although it ranges to 26S in the western and eastern parts of its range). The 26S line divides the grassveld (south) from the savanna (north) in this area. The Red-billed Buffalo-Weaver is clearly absent south of Pretoria, as in the past.

4. Range stable but low density in eastern corridor
The eastern population of the Red-billed Buffalo-Weaver in South Africa extends southwards in the savanna corridor from Mpumulanga, through the lowlands of eastern Swaziland, and into northern KwaZulu-Natal. The southernmost record is from the Zululand Rhino Reserve. The earliest published record from this corridor is of nests seen in July 1951. An earlier record is a specimen collected on 29 May 1937 in north-eastern Swaziland, suggesting that the species has occurred here in historical times, although early authors did not list it from here. The buffalo-weaver occurs at a very low density in this corridor, with the estimated population being 80 birds in Swaziland.

Range changes elsewhere

Botswana: expansion in SW (Tyler 2012a).
Uganda: recent new records (Rossouw 1998a, Demey 2011b).
Zambia: expanding north-eastwards in Kafue (Robertson 1995b).

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 [238] - Range changes [1]: Red-billed Buffalo-Weaver on 2017-01-04