Tiny Greenbul Phyllastrephus debilis Scientific name definitions

12·8–13·8 cm; male 13·3–17 g, female 12·5–14·9 g (nominate), male 13·5–17 g, female, 11·6–15 g, unsexed 11·9–15·1 g (rabai). Smallest African bulbul and smallest member of genus, differs from others in lacking nail on maxilla; sharply defined grey head and pale eyes. Nominate race has top of head and neck grey, lightly washed olive; lores and ear-coverts grey, slightly paler than crown, some indistinct paler streaking; upperparts dull olive-green, tail slightly browner but not contrasting, wings olive-green; throat white, breast and belly pale grey-white, washed greyer on flanks and across breast, some pale yellow streaking; lower belly and undertail-coverts light yellow-olive; iris white or creamy to pale yellow or golden; bill grey or blue-grey, paler mandible and cutting edges; legs black or grey. Sexes alike, female on average smaller than male. Juvenile (rabai) has top of head greener, similar to back. Race rabai has head and neck grey without greenish tones, upperparts bright olive-green, resembles nominate below but yellow tones brighter, belly yellowish white, undertail-coverts pale greenish yellow, bill variable, sometimes greyish horn or brownish, eye sometimes red-brown or dark grey-brown (possibly age-related).

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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.

Lowland evergreen forest, forest-woodland mosaic, thick coastal scrub, gallery forest; sometimes woodland, including miombo, but it is generally absent from Brachystegia. In coastal Kenya, common in Afzelia and Cyanometra-Manilkara forest. Appears to tolerate disturbed forest in parts of range, but recorded only in intact forest in others. Sea-level to 1550 m (in Tanzania).

Sedentary.

Insectivorous. Usually seen in pairs or in small parties of up to c. 10 individuals, sometimes singly; often joins mixed-species parties. Forages mostly in lower and middle strata (mostly below 4 m), but does sometimes ascend to canopy; generally keeps to dense undergrowth and lianas, and prefers thin branches and creepers; group-members constantly call to each other. Gleans insects from leaves with agility, reminiscent more of a Phylloscopus warbler (Phylloscopidae) than of a bulbul; flicks wings.

Alarm or contact call of rabai a rasping “chicidididididi”, rising in pitch, also low “churr’ and nasal “nnyeh nnyeh”. Song (given from canopy of forest) a series of short “chit” or “tut” notes mixed with lower, more nasal “nya” or “dya” sounds, e.g. “chitchitchit, chit-nya-nya-nya”.

Nesting recorded in Dec and May; birds in breeding condition in Oct–May in coastal Tanzania and Oct–Jan in Zimbabwe. Monogamous. Solitary nester, territorial. Nest a small neat cup of dark fibres, tendrils, black hyphae of Marasmius fungus, ferns, lichens and dry leaves, bound together with cobwebs, lined with fine plant stems; often asymmetrical (longer axis parallel with supporting twigs), external diameter 6–7 cm, depth 4·2–8·3 cm, internal diameter 3·7–5 cm, cup depth 2·2–4·9 cm; usually c. 1–2·1 m (range 0·4–5 m) above ground in horizontal fork of small tree, or where two or more horizontal twigs cross, often where a few large dead leaves trapped and which serve to conceal nest. Clutch two pale blue eggs blotched brown and grey, size 18·4–18·9 mm × 13·4–13·7 mm, mass 1·8 g; no information on incubation and nestling periods.

Not globally threatened (Least Concern). Generally common; apparent declines in N & S parts of range, implying that it is less common than it used to be in parts of Kenya and S Mozambique. Kenya’s coastal forests are subject to considerable and ongoing anthropological threats, with illegal removal and destruction of trees rampant, and many of the remnants survive only because of their status as sacred sites. Similar levels of threat face S Tanzania’s coastal forests. Occurs in a number of protected areas, including Arabuko-Sokoke, Gongoni and Shimba Hills Forest Reserves, in Kenya, numerous coastal forest reserves and Selous Game Reserve, in Tanzania, and Gorongosa National Park, in Mozambique.