Clarke’s Weaver Ploceus golandi

Weaver species list / RELATED SPECIES: Black-billed Weaver / Black-chinned Weaver / Black-necked Weaver / Clarke’s Weaver / Lesser Masked Weaver / Little Weaver / Loanga Weaver / Slender-billed Weaver / Spectacled Weaver / Strange Weaver / Tanganyika Masked Weaver

IUCN: Endangered Discovery: 107

Categories: wetland, fruit, IUCN

Discovery

Clarke’s Weaver, figure from Mackworth 1955a
Clarke’s Weaver distribution, type locality circled

 

Introduction

Clarke’s Weaver was formally described by Colonel Stephenson Robert Clarke, an English soldier and ornithologist.Clarke’s Weaver was first collected by a native collector employed by Stephenson Robert Clarke and his younger brother Goland van Holt Clarke, an English soldier and naturalist. Stephenson Robert Clarke wrote several notes on birds, including the description of this weaver, which he named after his brother (the latter did not write any papers on birds). The Clarke brothers collected birds in various parts of Africa and the rest of the world.

The Clarke brothers went on a shooting expedition to the Lorian Swamps in central east Kenya in 1912, where they collected many birds. They returned to Mombasa and from there sent a local collector to work along the coast as far as Lamu. The collector obtained several rare species, as well as a male Clarke’s Weaver. The weaver type locality was listed as Mombasa, where the brothers were based at the time, but would have been collected in the Arabuko-Sokoke Forest.

After the type specimen was collected in 1912, no more specimens were collected for 4 decades, so that Grant & Mackworth-Praed (1953) considered the type to be an aberrant, melanistic Lesser Masked Weaver. A second specimen was obtained in 1955 in the Sokoke Forest, however, by John Williams, after observing a flock and confirming it to be a valid species (Williams 1957b). In the late 1950s more specimens were obtained, including females.

The Clarke’s Weaver was first illustrated by Mackworth 1955a, showing the type male. The next illustration to be published was a line drawing by Harrison 1965c.

Scientific citation

Heterhyphantes golandi Clarke 1913a, Bull. Brit. Orn. Cl. 31: p.32, Mombasa, eastern Kenya Colony.

Meaning of names

golandi, Named after Captain Goland Clarke, one of the 2 brothers who first collected the species.

First English name

Coast Black-flanked Weaver (Someren 1922a).

Alternate names

Coast Black-flanked Weaver, Goland’s Weaver.

Collector

A native for Col. Stephenson Clarke and Goland Clarke.

Date collected

[Aug] 1912.

Locality collected

Along the coast between Mombasa and Lamu, Kenya.

Type specimens

The type is in the British Museum of Natural History (BM 1913.1.17.1).

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 [224] – Discovery [107]: Clarke’s Weaver on 2016-09-28

1. Basic biology

Clarke's Weaver
Clarke’s Weaver male,
figure from Colin Jackson
Clarke's Weaver
Clarke’s Weaver male & female with food,
figure from Colin Jackson

Identification. Clarke’s Weaver is a relatively poorly known species, with a limited global range. The male has a black head, breast and back, dark eye, slender bill. The similar Dark-backed Weaver, the only other forest weaver in its range, has a yellow belly (rather than pale yellow and white), dark rump and tail (rather than olive), and whitish wing feather edgings (rather than yellow edges).The female Dark-backed is like the male Dark-backed, while the female Clarke’s Weaver is dull with streaked upperparts, yellow underparts, and yellow wing edgings.

Distribution. Clarke’s Weaver is found only in the Arabuko-Sokoke Forest and Dakatcha area in south-east Kenya (see map above, based on Birds of Africa). Its total range is 535 km2, and in 1985 its population was estimated at 1000-2000 pairs. It is listed as “Endangered” (see Weavers by threat status), due to its restricted range, and it is vulnerable to forest clearance and wetland destruction.

Habitat. Clarke’s Weaver inhabits coastal forest and is most frequent in miombo (Brachystegia) woodland; it needs wetlands for breeding and has also recently been found to roost in wetlands (Nature Kenya).

Food. The diet of Clarke’s Weaver is mainly insects such as beetles, caterpillars and scale insects; but it also feeds on fruits of Loranthus and Brachystegia spicifomis.

Clarke’s Weaver forages mostly in the canopy, in feeding flocks of up to 30, occasionally more than 100 individuals. It sometimes joins mixed-species flocks, especially helmet-shrikes (Prionops species). It may be found in single-sex flocks. At times it is conspicuous and gregarious, but flocks appear erratically. Other bird species apparently hawk insects that are flushed by the weavers, which are shy and restless.

Clarke's Weaver
Clarke’s Weaver nest, figure from Colin Jackson

Breeding. Nothing was known about breeding until an active colony was discovered in March 2013 (News). This date fits in with the suspected breeding season of February-March when the rains begin, since juveniles have been seen from March to August. It was a large colony, and Brian Finch estimated some five hundred nests concentrated in the small area of sedges (Nature Kenya). The monitoring team from Nature Kenya and the Dakatcha Woodland Conservation Group estimated that at least 700 birds were present. Adult weavers were bringing insects to the colony to feed nestlings (eg female in photo, top right).

Nests were built of sedges, and the shape of the nests varied between rounded or oval, to more pouch-shaped Jackson 2015a). A second breeding colony was found in 2015 (News). Details of breeding (mating system, clutch size, egg colours and sizes, incubation and nestling periods, etc) are still unknown.

Read more about the discovery of the colony here.

The above is based on Weaver Wednesday, a weekly series about weaver species.
This species text first appeared as Weaver Wednesday [62]: Clarke’s Weaver on 2013-08-21

2. Breeding facts

Pair bond
No information


Breeding season
Juveniles recorded in Apr and Jul-Aug, and male in breeding condition in Sept


Nest site
No information; It is speculated that nests may be high in trees


Nest building
No information


Colony size
No information


Clutch size
No information


Egg colour
No information


Egg size
No information


Incubation
No information


Chicks and nestling period
No information


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

3. Photos of Weaver Nests


Vm 28236

Vm 27552

Vm 20379

Vm 5624

Thumb-nails of recent PHOWN records