White-browed Sparrow-Weaver Plocepasser mahali Scientific name definitions

17 cm; 31–59 g. Large sparrow-like weaver with broad white eye­stripe and white rump. Nominate race has forehead and crown chocolate-brown, broad white eyebrow, brown cheek and ear-coverts, blackish malar stripe; nape to back mantle brown, paler than crown, rump and uppertail-coverts white; upperwing and tail brown, the feathers tipped white, on greater and median wing-coverts forming bold wingbars, narrow pale edges on remiges, broader ones on tertials and inner secondaries; white below, some buffy wash on flanks; iris rich chestnut-brown to dark brown; bill pale brown or black (possibly changing seasonally); legs brown. Sexes alike in plumage; in some populations, only male has black bill. Juvenile has dark bill, dull brown eye, plumage like adult. Race pectoralis has mantle and back reddish-brown, breast feathers marked with dark triangular centres; ansorgei has broad white tips on tail feathers; <em>melanorhynchus</em> has earthen-brown upperparts , and black marks at side of breast continuous with malar stripe.

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Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Inhabits open mopane (Colophospermum mopane) and acacia (Acacia) savanna in areas with annual rainfall exceeding 600 mm; generally occurs below 1400 m, but ranging locally up to 1900 m.

Mainly resident. Some local movements away from breeding sites; birds dispersing from natal group often leave as a cohort, initial movement seldom more than 1 km, but after several successive moves may settle more than 5 km away. Males disperse to longer distances than females, as shown both by direct observations and a population genetic analysis (1 Harrison, X.A., York, J.E. and Young, A.J. (2014). Population genetic structure and direct observations reveal sex-reversed patterns of dispersal in a cooperative bird. Molecular Ecology. 23: 5740–5755. Close ).

Diet insects and seeds , proportion of arthropod food varying both regionally and seasonally. In South Africa, up to 50% of diet insects, e.g. termites (Isoptera), especially harvester termites (Hodotermitidae), beetles including weevils (Curculionidae) and tenebrionids (Tenebrionidae), caterpillars and adult moths (Lepidoptera) and ants (Formicidae); readily takes bread and other scraps at camp-sites. Seeds taken include those of wild grasses, e.g. Urochloa, Stipagrostis, Simeam fenestratum, Digitaria velutina, Eragrostis papposa, Cenchrus ciliaris, Dactyloctenium aegyptium; cereal crops such as sorghum (Sorghum), millet, wheat (Triticum) and maize (Zea mays) important at times. Forages primarily on ground, running or hopping in pursuit of prey; rolls over stones or dung pats, digs in soil, searches underside of vegetation. Hawks insects, especially termite alates. Occasionally joins mixed-species flocks of insectivorous birds in acacia woodland in South Africa. Not seen to drink in semi-desert areas of Botswana, but noted as drinking and bathing in Mountain Zebra National Park, in South Africa.

Solo song of dominant male in group is highly individual, with complex chattering and squealing notes in unbroken sequence lasting for 6–20 minutes. Duets, performed primarily by breeding pair, are short (c. 5 seconds) series of matching syllables; territorial chorus song by group-members short and stereotyped. Both song types heard throughout year. Captive young first sang within a week of fledging. Alarm and vigilance call a short "chuk"; a shriller chirp in flight; in Kenya, utters alarm calls in response to people, vervet monkeys (Cercopithecus aethiops), Pearl-spotted Owlet (Glaucidium perlatum) and Fan-tailed Raven (Corvus rhipidurus).

Breeds throughout year in Kenya and South Africa, depending on local conditions in areas of irregular rainfall; mostly Mar–May in E Africa, but Jul–Aug on Laikipia Plateau (Kenya); Nov–Dec in Angola, peak Dec–Mar in Zambia, Oct–Feb in Malawi, May–Jun in Botswana, and Sept–Nov in Zimbabwe; mostly Nov–Feb in South Africa. Monogamous; dominant breeding pair in small territorial group of 5–9 (occasionally up to 20) individuals, and co-operative breeding system with helpers, which either offspring of breeders or unrelated birds; unrelated helpers participate only in group defence of territory, whereas related helpers also feed young. Competition for status apparently correlated with levels of luteinizing hormone, rather than testosterone; breeding male may be replaced by outsider or by a group-member; dominant individuals not physically larger than other group members of same sex. Nests built throughout year, but especially after rain, used for roosting by individual birds; a horizontal cylinder of dry grasses (983 grass stems in one nest) 30 cm long and 18 cm in diameter, resting on supporting branches with entrance at each end, grasses bent but not woven, construction taking 10–18 days; c. 60% of such nests converted to breeding nests by closing of lower entrance, then lined with feathers, particularly from guineafowl (Numida) (858 feathers in one nest), with pasque flowers (Pulsatilla patens) reported as lining in one nest; placed 2–8 m above ground in tree such as mopane, Sclerocarya caffra, or acacia (at least six species recorded), compass orientation apparently dependent on prevailing wind direction; in S Africa, nests used for roosting also by Ashy Tit (Melaniparus cinerascens), Red-headed Finch (Amadina erythrocephala) and Black-cheeked Waxbill (Estrilda erythronotos), and in N Namibia used for breeding by Rosy-faced Lovebirds (Agapornis roseicollis). Clutch 2–3 eggs, salmon-pink or creamy white, either evenly speckled with red, brown and grey, or markings forming band at thick end, average 24·9 x 16·4 mm (South Africa); incubation by female alone, period 14–16 days; young fed by female alone for first 2–3 days, then also by male and helpers, chicks in nests with helpers grow faster; nestling period 17–18 days in Zambia, 21–23 days in South Africa, 25 days in captivity; young still fed occasionally for up to 3 months after leaving nest. Success from egg to fledging 38% in South African study, 46% in Zambia; predation main source of nest losses, with vervet monkey, Shikra (Accipiter badius) and African Harrier-hawk (Polyboroides typus) recorded as predators. Ringed adult at least 10 years old in South Africa; estimated annual survival of adults at colonies in Zambia and Kenya more than 70%, with improved survival in larger groups.

Not globally threatened. Generally common; abundant in many semi-arid areas, and population in Zambezi Valley, in WC Mozambique, estimated at more than 1,000,000 individuals. Less common in protected areas in South Africa, with c. 500 birds in Kgalagadi Transfrontier Park, and at least 60 colonies in Mountain Zebra National Park, close to S limit of range; this region colonized over past 40 years.