White-throated Blue Swallow Hirundo nigrita Scientific name definitions

12 cm; 15–22 g. Plumage is mostly glossy steel-blue with purple sheen, white patch on throat ; wings black with purple gloss; tail almost square, black with blue gloss, white patches on inner webs of feathers (except central pair); blackish underwing-coverts . Sexes alike. Juvenile is duller and browner than adult.

Sierra Leone, SE Guinea, Liberia, and S parts of Ivory Coast, Ghana, Benin and Nigeria, E to SW Central African Republic and DRCongo (except NE & SE) and S to N Angola (S to Cuanza Norte, Malanje and Lunda Sul); possibly also extreme W Uganda (R Semliki).

Rivers and streams in rainforest; also mangroves, harbours, land spits and lagoons.

Resident; possibly some local movements. Apparently present in Sierra Leone only Dec–Jul.

Diet includes dipterans, especially horseflies (Tabanidae), also beetles (Coleoptera), Odonata, termites (Isoptera), Hymenoptera. Forages mostly in pairs, occasionally in small groups, once of over 40 individuals. Flight rapid, with frequent banking, occasional gliding. Sometimes hawks insects from riverbank perch or from rock or overhanging branch.

Song is a weak twittering; calls  include a “weetch”, a “vwhit vwhit” and a soft “whit” uttered in flight.

Mainly in dry season, when river levels low: Mar in Sierra Leone, Oct–Mar in Liberia, Jan and Jun in Ghana, Jan–Feb and Aug in Nigeria, Jan–Feb and Jun in Cameroon, Jan–Mar and Jun–Aug in Gabon, Jan–Feb, Jul and Dec in DRCongo, and Mar–Apr and Aug in Angola; sometimes double-brooded. Solitary; aggressive towards intruders, pair keeps to limited area around nest-site. Nest built by both sexes, taking c. 3 weeks, an open cup made of mud pellets with some dry grass, lined with bark, grass and feathers, usually affixed under horizontal surface and generally 1–3 m (sometimes as little as 10 cm) above water and more than 5 m from riverbank, on rock, fallen tree or overhanging branch or cliff, but also recorded on artificial site such as bridge, pier, upturned canoe, or roof of house near water; nests sometimes reused. Clutch 2–3 eggs, rarely 4; incubation by female, 15 days or more; chicks fed by both sexes, fledge at 17–18 days; family-members stay together for a while.

Not globally threatened. Locally common. Recorded density 1–2 nests/km of river. Recently recorded on Ugandan side of R Semliki, but not known if breeding there. Only occasionally exploits artificial nest-sites, but this habit (especially use of bridges) may be increasing.