HBW 7 - Species accounts: Yellow-rumped Tinkerbird (Pogoniulus bilineatus)

20. Yellow-rumped Tinkerbird
Pogoniulus bilineatus

French: Barbion à croupion jaune  German: Goldbürzel-Bartvogel  Spanish:Barbudito Culigualdo

Other common names: Golden-rumped Tinkerbird/Tinkerbarbet; Lemon-rumped Tinkerbird/Tinkerbarbet (leucolaimus); White-chested Tinkerbird/Tinkerbarbet (“makawai”)

Taxonomy. Megalæma bilineata Sundevall, 1850, Natal.
Appears to be most closely related to P. subsulphureus and the superspecies formed by P. pusillus and P. chrysoconus; possibly fairly close to P. atroflavus. Yellow-rumped races mfumbiri, leucolaimus and poensis have been thought to represent a separate species, P. leucolaimus, but they intergrade with the three golden-rumped races in E Zaire, Rwanda and Burundi; also, vocal evidence suggests that leucolaimus is conspecific with present species. In view of similarity and intergradation between these two groups, other described forms considered untenable: thus, sharpei (S Ghana), togoensis (Gambia to S Nigeria) and nyansae (W shore L Victoria) regarded as synonymous with leucolaimus; urungenis (S shore L Tanganyika) with mfumbiri; alius (C Kenya) with jacksoni; pallidus (Sokoke Forest) and conciliator (Uluguru Mts) with fischeri; and rovumensis (SE Tanzania), deceptor (E Zimbabwe), riparium (S Mozambique, NE South Africa) and oreonesus (­Malawi) with nominate bilineatus. In addition, single specimen from NW Zambia originally described as separate species, “P. makawai”, on basis of plumage differences and bigger bill, but now generally considered no more than aberrant individual of present species. Six subspecies recognized.
Subspecies and Distribution.
P. b. leucolaimus (J. Verreaux & E. Verreaux, 1851) - Senegambia E to S Cameroon, S Central African Republic and W Uganda, S to N Angola, and S Zaire.
P. b. poensis (Alexander, 1908) - highlands of Bioko I (Fernando Póo).
P. b. mfumbiri (Ogilvie-Grant, 1907) - SW Uganda and E Zaire to W Burundi, W Tanzania and E & NC Zambia.
P. b. jacksoni (Sharpe, 1897) - E Uganda and C Kenya S to E Burundi and N Tanzania.
P. b. fischeri (Reichenow, 1880) - coastal Kenya S to NE Tanzania; also Zanzibar, and Mafia I (off E Tanzania).
P. b. bilineatus (Sundevall, 1850) - E Zambia and S Tanzania S to E South Africa.

Distribution Pogoniulus bilienatus Descriptive notes. 10-12 cm; 11-18·5 g, but fischeri 8-12·5 g, and leucolaimus 7-14 g. The epitome of a tinkerbird, with contrastingly marked face, strong bill, rather short tail. Both sexes of nominate race black above, with golden rump, golden-yellow in wings; white supercilia, white line across forehead and down to neck side, white throat; underparts pale olive-yellow, more olive laterally. Distinguished from similar P. subsulphureus by larger size, white throat, more golden rump, from very similar white-throated race chrysopygus of latter also more safely by voice. Immature duller, greener, less black than adults, with yellow base of bill. Races differ mainly in coloration of pale areas of plumage, forming two groups according to rump colour: jacksoni and fischeri golden-rumped like nominate, former smaller, greyer and less olive below, and paler generally, fischeri very small, with whiter throat, yellower rest of underparts, larger gold rump, and becoming clinally paler to N; other three races all yellower-rumped, mfumbiri large and with buff on sides and flanks, leucolaimus small and brighter yellow, with even less olive, and poensis paler yellow on rump and underparts and with whiter breast.
Voice. Usual song paused popping, series of “pop” notes at c. 3 per second, in sets generally of 2-6, more in some situations, first and last sets with fewest notes; N birds of race fischeri substitute “pop-trill” for paused popping, more S individuals of same race employ both songs; occasional nasal “honk”, lacking overtones, within popping song; also pure “honk” calls in series, especially at start of and after breeding, also so-called “frog” call “driii-driii-”, with burry “rrrrrk” perhaps a version of it; also “pop-op” calls in series, sharp “chip” notes, rattling “bdddddt” in interactions, common “zddddd” grating calls with elements at c. 90 per second, and begging “di-di-di-”. Mechanical signals include wing-fluttering, bill-tapping at or in cavity.
Habitat. Forested highlands and lowlands, especially at edges, about clearings, in forest clumps left over after clearing, in thickets, riverine forest, moist parts of drier woods, tree plantations, and gardens. In coastal Kenya, shares forest habitat with P. simplex, more open wooded habitats with P. pusillus; in C & W Africa less often in dense forest than is smaller P. subsulphureus, but occurs with it and with P. atroflavus and P. scolopaceus. On Bioko, is a highland species generally occurring above P. subsulphureus; elsewhere, may impinge on highland P. leucomystax and P. coryphaeus. Occurs from sea-level to 1800 m in W Africa, to 2600 m in C Africa and on Bioko (where usually above 800-1000 m), to 3000 m in E Africa, c. 1600 m in Zimbabwe and 600 m in South Africa.
Food and Feeding. Fruits essential, including especially mistletoe berries (Loranthus, Tieghemia, Sulphurea, Viscum), also Ficus, and species of Allophyllus, Clausenia, Ekebergia, Macaranga, Maesa, Ochna, Ocotea, Polyscias, Prunus, Psychotria, Trema and others; insects also taken, including termites, ants, noctuid moths and other Lepidoptera, Homoptera, curculionid and galerucid beetles, among others. Discards epicarp of mistletoe berries as fruits eaten, cellulose layer is digested, pectin layer over seeds passes through digestive system and egested with seed; small berries swallowed, regurgitated in courtship feeding. Insects caught by gleaning and flycatching, even in exotic trees. Isolated fruiting trees may be defended by a single bird.
Breeding. Nov-Apr in W Africa; all year in Cameroon, Apr-Nov and Jan in Gabon, Congo and Zaire; May-Jun in Uganda; Jan-Mar and Aug in W Kenya, Mar-Jul and Sept-Jan in coastal Kenya and Tanzania, May-Aug and Nov-Feb (during and after rains) in C Kenya and EC Tanzania; Apr-May and Sept-Dec on Mafia I and Zanzibar; Oct-Jan in Angola to Zambia and Malawi, and eggs in Sept-Dec in South Africa; sometimes 2 broods in a season. Singer erects rump feathers, puffs throat, flicks tail with each note, turns head side to side in almost vertical posture; courtship feeding of up to 32 berries in 25 minutes, sometimes followed by copulation (e.g. 3 times in 25 minutes). Nest, excavated by both adults, 1-10 m up in dead tree, stump, post or dead branch; entrance diameter 2·5 cm, cavity 2·5 cm into branch, 40-100 cm deep, nest-chamber 3·5 cm by 5 cm, lined with wood chips; territory c. 4 ha. Eggs 2-5, usually 3; incubation c. 12 days, by both adults; chicks fed insects at first, later also fruit, at rates of up to 19 feeds per hour; nestlings’ faecal material eaten at first by parents, later young present anal area to adult, which then carries away faecal sac, in one instance 12 sacs removed after 38 feeds in 2-hour period; fledging at 17-20 days; few data on post-fledging period, but occurrence sometimes of second brood suggests rapid independence. Up to 4 young fledge; nests parasitized by Least (Indicator exilis) and Scaly-throated Honeyguides (I. variegatus), and also recorded by Pallid Honeyguide (I. meliphilus); 1 tinkerbird pair enlarged cavity entrance apparently to facilitate exit of large young honeyguide.
Movements. Resident, and largely sedentary, but dispersal up to 20 km.
Status and Conservation. Not globally threatened. Form “makawai” officially considered Data-deficient. Widespread, and common throughout range; generally commonest tinkerbird wherever it occurs, although in Liberia far less numerous than P. subsulphureus. Adapts to various habitat changes. Despite searches having been carried out, “makawai”, now thought almost certainly to be variant of present species, not recorded in the 35 years since first discovered, in 1965.
Bibliography. Anon. (1998d), Bannerman (1933, 1953), Barlow et al. (1997), Bennun (1991), Benson & Benson (1977), Benson & Irwin (1965a, 1965b), Benson et al. (1971), Britton (1980), Brosset & Érard (1986), Brown & Britton (1980), Cave & Macdonald (1955), Chapin (1939), Cheke & Walsh (1996), Christy & Clarke (1994), Clancey (1971c, 1985c), Collar & Andrew (1988), Collar & Stuart (1985), Collar et al. (1994), Colston & Curry-Lindahl (1986), Day (1981), Dean (2000), Dowsett (1979a, 1980, 1990), Dowsett & Dowsett-Lemaire (1980, 1993), Dowsett & Forbes-Watson (1993), Elgood et al. (1994), Field (1999), Friedmann (1930a, 1978a), Fry et al. (1988), Gatter (1997), Ginn et al. (1989), Goodwin (1965), Gore (1990), Grimes (1987), Harrison et al. (1997), Irwin (1981), Lewis & Pomeroy (1989), Lippens & Wille (1976), Liversidge (1991), Louette (1981b), Mackworth-Praed & Grant (1957, 1962, 1970), Maclean (1993), Madge (1971), Milstein (1995), Mlingwa (2000), Pakenham (1979), Pérez del Val (1996), Pérez del Val et al. (1994), Pinto (1983), Pitman (1929), Prigogine (1972, 1977, 1980a, 1985), Rand et al. (1959), Serle (1950), Short & Horne (1985a), Short et al. (1990), Snow (1978), van Someren (1956), Tarboton (2001), Thiollay (1985a), Vande weghe (1980), Ward (1989), White (1953), Zimmerman (1972), Zimmerman et al. (1996).