Introduction

The Slender-billed Weaver was collected by Emin Pasha, an Ottoman-German physician, naturalist, and governor.

After 1876, Emin made Lado his base for collecting expeditions throughout the region, and here he collected his weaver type, the Cardinal Quelea.

In November 1879 Pasha sailed south on a steamer called "Khedive" on the Nile to lake Albert. He devoted his stay at Magungo as far as possible to collecting specimens (including birds, snakes and insects), although he had little ammunition and spirit for preserving specimens. In a letter, Pasha noted that he had found 5 species of weavers in the area, but he only listed the Thick-billed Weaver. Pasha collected 3 specimens of the Slender-billed Weaver in Dec 1879 near Magungo. In 1880 he donated the specimens to Rudolf, Crown Prince of Austria, who passed them on to the Museum in Vienna. One of the specimens was swopped to go to Bremen where Hartlaub recognised it as a new species in 1887.

The first illustration of the Slender-billed Weaver was published by Hartlaub (1887), with the description of the species. The next illustration to be published was a line drawing by Sharpe (1890).

Scientific citation

Meaning of names

First English name

Alternate names

Collector

Date collected

Locality collected

Type specimens

Distribution. The Slender-billed Weaver is found from West Africa across to Lake Victoria. Two subspecies of the Slender-billed Weaver are recognised (see map left, based on Birds of Africa):

P. p. pelzelni, in NE DRC, Uganda, SW Kenya, Rwanda, Burundi, and NW Tanzania (see red on map).
P. p. monacha, in W Africa from Ivory Coast to Cameroon, and Gabon, Congo, W and S DRC, NW Angola, and NW Zambia (see blue on map). The bill is shorter and less slender than in the nominate subspecies.

Habitat. The Slender-billed Weaver is restricted to wetland areas for breeding, foraging in trees and bushes in adjoining habitats. In western Africa it inhabits mangroves, coastal lagoons, marshlands and ricefields. In southern DRC it occurs in ambatch thickets bordering lakes, and also in gardens and hedges in urban areas. It usually occurs below 1700 m but up to 2350 m in the Ruwenzoris. The Slender-billed Weaver is found singly or in pairs or in flocks.

Food. The Slender-billed Weaver feeds mainly on insects, including small caterpillars and ants. Seeds have also been recorded. It forages at all levels in trees. It is agile and often hangs upside down when foraging. The foot structure shows adaptations to a papyrus habitat.

Breeding. The Slender-billed Weaver is a monogamous, colonial nester. Colonies are usually in groups of less than 20 nests, but sometimes up to 50, or single nests at about 12 m apart. It may breed alongside mixed colonies of other weaver species. The nest is ball-shaped, tightly woven, without an entrance tunnel or with a very short tunnel, with a porch over the side-top entrance. The nest is made of grass strips or papyrus leaf, and some nests include dead pieces of vine stem. There is no ceiling as in the nests of some weavers. During incubation a sparse lining of very fine strips of grass, palm leaves, feathers or seed-heads may be added.

The nest is attached to papyrus heads, or in trees (thorny twigs or small palms) at a height of 1.5-9m (usually about 3m) above the ground. The nest is built by the male, with the female sometimes helping. Sometimes two nests are built on the same stem, but only one is occupied.

Clutch size is 2-3. The eggs are pure white or sometimes pinkish, rarely with fine spots. In Kisangani it breeds all year, but peaks in September. It is parasitized by cuckoos, most likely the Diderick Cuckoo Chrysococcyx caprius. Nests have been robbed by Pied Crows Corvus alba and Senegal Coucals Centropus senegalensis.

Old nests of the Slender-billed Weaver may be used by Dusky-blue Flycatchers Muscicapa comitata.