Straw-tailed Whydah Vidua fischeri Scientific name definitions

10–11 cm, breeding male 30–32 cm; 9–17·8 g. Male breeding is distinctive, has forehead and crown yellow , rest of head and entire upperparts black, becoming browner on wing, black ­continuing down to upper breast, rest of underparts yellowish-buff; under­wing-coverts dark grey; tail short, brown (tips and edges buff when fresh), central two pairs of rectrices (T1 and T2) greatly elongated (more than 20 cm long), narrow (2–3 mm wide, with fine barbs along shafts) and straw-coloured; iris dark brown; bill orange to coral-red; legs orange. Non-breeding male similar to female, but upperparts more boldly marked. Female has head nearly unstreaked dark rufous to pale chestnut, nape buff with darker streaks, face plain pale buff, indistinct pale superciliary stripe, upperparts dark-streaked rusty brown, upperwing brown with paler brown edgings, tail brown (tips and edges buff when plumage fresh); throat whitish, breast sandy buff, belly whitish, underwing-coverts brownish-grey; bare-part colours much as for male. Female and non-breeding male differ from Red-billed Quelea (Quelea quelea) in having orange-red (not pinkish-red) bill and legs, nearly unstreaked head with rufous wash, and brown (not yellow) wing edgings. Juvenile is mostly rusty brown, paler below, unmarked or with indistinct streaks on back, tail brown; iris dark brown, bill black, legs brown; bill and legs change to orange when bird begins to moult into streaked plumage.

SE South Sudan (E side of Dongotona Mts, E side of Didinga Mts, Kapoeta and Kenyan border), Ethiopia, Somalia, NE Uganda (rare), Kenya, and Tanzania (dry C plateau from Serengeti and Masai steppe S to Tabora, Morogoro and Iringa region).

Short-grass plains with patches of open ground in arid and semi-arid dry thorn-scrub and bush country; below 1600 m.

Small grass seeds, also larval and adult insects, taken from ground . Breeding male forages within his territory; female often feeds with male. Occurs alone or in flocks in breeding season; in non-breeding season mainly in flocks, sometimes with other species, including Purple Grenadier host.

Mimics songs and calls of host, Purple Grenadier (Granatina ianthinogaster): (1) loud song a series of short notes ending with 4–5 high, rising whistles, "cheerer cheet tsee-tsee sur-chit-cheet-chit-tsereea", the long whistle ("tsereea") gliding up or down in pitch (varying regionally; (2) trill song, introduced by whispers, has short trills in middle, and ends with short trill or single whistle on one pitch; (3) contact call a thin "wis-wis"; (4) contact trills (c. 10 notes per second); (5) excitement trills, "chay-chay-chay"; (6) sharp "tsek" in alarm, with notes often run together in a chatter; also nest calls and begging calls. Male gives medley of these songs and short chatters when displaying to visiting female, also when alone. Non-mimetic song different, a variable repertoire of chatters, whistles and harsh notes. Non-mimetic song irregularly alternates with bouts of mimicry, and given when male chases another, or when male gives "wing-whir" or "hover-hold" display to female. Non-mimetic calls include chatters, rapid (30 notes per second) or slow (15–16 notes per second), and buzzy "chuz" singly or in series, the phrases delivered in different combinations and not in standard song themes. Individual gives chatters from age of 32–35 days, songs within first year.

Males in breeding plumage in Dec and May in Sudan and May–Dec in Somalia; breeding plumage in Apr–Jun and Dec and juveniles in Aug–Nov in Ethiopia; in Kenya, laying Feb–Jun in S and copulation observed Aug–Sept in W; lays Mar–Jun in Tanzania. Male sings from sunrise through heat of mid-day to sunset (song bouts as long as 60 minutes), in top of bush in display arena of c. 2500 m²; flies from bush to bush, tail jerking, chases off intruding male by flying below and behind until intruder leaves territory. In courtship display, male sings from perch, beats a rhythm with wings as he holds on to perch with legs extended for up to a minute, looks around; when female visits, he displays and takes her to ground, where pair feeds on seeds, pair then returning to copulate on a call-site bush. When female visits, he chatters and then directs "hover-hold" display to her, and bows head, showing his yellow cap and breast; if she stays on perch, he flies to her and hovers, bobs up and down, and quivers and flops long tail; female may crouch and quiver wings, he mounts, but more often he flies to ground and sings, she joins him, and the two forage while he continues to sing; she then flies away and visits other males. Brood-parasitic, lays in nests of Purple Grenadier , perhaps also in those of Blue-capped Cordon-bleu (Uraeginthus cyanocephalus), latter the only estrildid breeding at Kapoeta and Sudan-Kenya border when present species active (in Dec); in Tanzania, 11 of 15 nests of grenadiers were parasitized by this species; eggs laid one per day for 3 days, then a few days before next set, eggs white, unmarked, 15·5 x 12·5 mm; no information on incubation period. Hatchling has skin purplish-black, down grey, palate centre whitish with three black spots, tip dark grey, medial area behind spots orange, grading to whitish and pale blue on sides, rest of palate black, oral surface of gape black, dorsal gape swelling large and blue, ventral one small and pale blue, band around gape dark blue to purplish-black, tongue black with white edges, lower mandible black; mouth pattern orange and blue, similar to that of nestling Purple Grenadier; by time of fledging is rusty brown, like host's young but without blue rump and uppertail-coverts and black tail; nestling period c. 18 days. Female breeds in first year; male in full breeding plumage and song when 1 year old.