White-browed Treecreeper Climacteris affinis Scientific name definitions

14–16 cm; 21 g. Male nominate race has broad white eyebrow contrasting with black lores, tapering above ear-coverts, which are streaked black and white; crown and hindneck dark grey, grading into brown on mantle and scapulars; rump, upper­tail-coverts and uppertail grey, black subterminal tailband; upperwing blackish-brown, grey tertials, broad buff bar across middle of remiges; chin white, grading to pale brownish-grey on throat and upper breast, with lower breast, belly, vent and flanks boldly striped black and white ; undertail-coverts white with broken black bars; iris dark brown; bill and legs black. Female differs from male in having eyebrow bordered above by thin reddish-brown line, and centre of upper breast striped reddish-brown and dull white. Juvenile has duller facial pattern, with supercilium and streaking on ear-coverts less distinct, also bill pale grey, with pinkish-grey at base of lower mandible, gape white; young female has rufous markings on supercilium and upper breast less distinct than on adult. Race superciliosus differs from nominate in having rump, uppertail-coverts and tail same colour as mantle (not grey).

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No detailed studies. Food mainly ants (Formicidae), but also small numbers of spiders (Araneae), beetles (Coleoptera), moths (Lepidoptera), flies (Diptera), termites (Isoptera), and various insect larvae. Arboreal and terrestrial. Ascends trunks and branches of both living and dead trees, and hops along fallen trees, among logs and litter, and on bare ground, particularly where abundant shrubs; sometimes feeds at ant nests.

Main call a ringing insect-like trill, sometimes described as “rasping call”; also a louder whistle, “tinker-tinker-tinker”. Calls not well understood, as given infrequently.

Season Jul (Western Australia) or late Aug (Victoria) to late Nov, but timing differs from one year to another; majority attempt second brood in years with good rainfall. Breeds as pair, or co-operatively in group consisting of one breeder of each sex and up to three helpers, invariably males; in sole detailed study (in NW Victoria), 65% of 26 breeding unit-years involved unassisted pairs, and remaining pairs had one helper (31%) or three helpers (4%). Both parents and helper males brought material to nest, continuing during incubation; nest composed mainly of bark fibres and dried grass, lined with fur, hair, wool, feathers or vegetable down (some nests entirely of fur or wool), placed in tree hollow (depth of 13 hollows 8–42 cm, mean 17·4 cm), often in dead tree or dead limb of live one, with entrance through hole or split in trunk or in open end of broken limb; of 17 nests at one locality, 82% in live (versus dead) tree and 71% in belah, and 85% of 13 nests were in trunk (as opposed to limb); 20 nests over entire range 1·1–5 m (mean 2·3 m) above ground, and 17 nests in NW Victoria 2–5·2 m (mean 3 m) up; territory all-purpose, permanent, 6·6–11·2 ha (mean 8·4 ha), size not correlated with group size. Clutch 1–3 eggs, usually 2 (mean of 38 clutches in NW Victoria 1·95, of 13 in Western Australia 1·85), slightly lustrous, pinkish-white, thickly freckled and spotted with reddish and purplish-brown, especially at thicker end; incubation by breeding female only, fed (usually at nest entrance) by male and helpers, female’s attentiveness varied, females in pairs incubated for 45% of time during first 10 days and 58% thereafter, those in groups for 58–59% of time over entire period; incubation period 18 days; chicks brooded by female for at least 7 days after hatching, for average of 53% of time in four pairs, fed by both parents and any helpers, in one study 7·3 feeds per hour; in first week, hourly feeding rate among pairs (4·75 feeds) lower than among groups (6 feeds), but by third and fourth weeks pattern reversed (10·1 and 7·7 feeds, respectively); also during first week, female provided 37% of food when in pairs (1·75 feeds per hour) and 17% of food in groups (1 feed/hour), but by third week provided 47% (4·8 feeds/hour) in pairs and 31% (2·4 feeds/hour) in groups; proportion and rate of feeding by female higher for pairs (43%, 3·2 feeds/hour) than for groups (31%, 2·2 feeds), and for groups helpers provided 26% of food overall (1·8 feeds/hour); nestling period 26 days; dependent for less than 37 days after fledging. Mean annual adult survival of a population in NW Victoria 72–85%, higher for males (75–87%) than for females (69–84%).