Black-billed Sicklebill Drepanornis albertisi Scientific name definitions

Male 35 cm, 103–125 g; female 33 cm, 92–138 g. Fairly large paradis­aeid with very long, sickle-shaped bill and medium-length tail. Male nominate race  has head variably cinnamon-brown, browner on crown, where feathers tipped iridescent coppery purple; lores, chin and throat blackish, strongly tainted iridescent leaf-green; elongate forecrown feathers form "horn" above front edge of each eye, with some shorter feathers tipped iridescent purple-blue and longer ones magenta; bare facial skin dark maroon-grey; upperparts and upperwing cinnamon-brown, rump and upper­tail-coverts paler, tertials and primaries with broad cinnamon leading edges; uppertail pale cinnamon; sooty-brown to sooty-grey upper breast separated from lower breast and flank plumes of same colour by band of feathers broadly tipped iridescent violet-purple with magenta wash; loosely structured pectoral plumes iridescent bronze with magenta wash, and similarly structured elongate flank plumes broadly tipped purple; central belly, vent and undertail-coverts white; iris dark brown; bill shiny black, mouth pale green or pale yellow; legs brownish to greyish or blackish. Female is similar to male in size and weight, lacks iridescent feathering, but otherwise similar above to adult male but darker and more amber on tail; chin and throat cinnamon-brown with fine pale, buffy central feather shafts, underparts barred dark brown throughout except on lower breast, where feather barring forms chevrons. Juvenile undescribed; immature like adult female, but with longer tail than both adult sexes; subadult male varies, from similar to adult female with few feathers of adult male plumage intruding to much like adult male but with few feathers of female-like plumage remaining; adult male plumage exhibited patchily for at least one breeding season, horns over eyes usually acquired at same time as iridescent green throat, iridescent purple-tipped flank plumes and extensive central breast patch of olive-brown, barred female-like plumage remaining above and below latter; male tail length decreases slightly with age. Race <em>cervinicauda</em> is smaller than nominate, with proportionately shorter tail, paler uppertail-coverts and tail, underparts of birds in female-type plumage pale buff with paler brown barring.

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Middle montane forests, infrequently logged areas and forest edge; 600–2250 m, mainly 1100–1900 m.

Presumably resident. A female was silent while moving about her 43-ha range during period of eight days.

Primarily insectivorous, taking various arthropods, but also fruits (mostly capsules). Forages mostly in middle and upper levels of forest. Gleans, prises, and probes bark, dead wood, limb surfaces, mosses, dead leafy debris and knotholes for prey; uses bill as forceps to pick up items or to remove fruit from capsular husks; entire bill or either upper or lower mandible used for probing holes. At least individuals in female-type plumage join mixed-species foraging flocks.

Male advertisement song a high, powerfully whistled, musical "dyu dyu dyu dyu dyu dyu dyu...", increasing in speed and rising (sometimes falling) in pitch; contact a plaintive "wrenh"; display call a variable elaboration of advertisement song but higher, more insistent, faster, ending with sibilant "tish-tish-tish-tish-tish-tish-tish-tish" or "ki-ki-ki-ki-ki-ki-ki". One male preceded displays by whistling "to to to to to to to to" followed by harsh but softer note. Vocalization on Fakfak Mts a series of downslurred whistles slightly decelerating and rather slowly delivered, distinct from that on Arfak Mts, which is a much more rapidly delivered trill like that of a Whimbrel (Numenius phaeopus).

Breeds at least Sept–Dec, and birds with enlarged gonads noted Feb–Oct over entire range, but little studied; a begging juvenile following its mother at end Nov; display season at Mt Missim (E New Guinea) May–Nov, virtually silent in intervening months, and mating mostly Oct–Nov or shortly before or after in EC New Guinea. Polygynous, solitary promiscuous male advertisement-singing/displaying from one or more traditional perches; female builds and attends nest alone. Adult male territorial, occupying and defending large display/foraging all-purpose territory all year, adjacent males in auditory contact from high posts, displays at habitual site involving several perching areas, descending to saplings to court females; display calls typically given in lower forest, to within a metre of ground; an individually marked male's territory was c. 14 ha (mean nearest-neighbour distance between display sites of five males 450 m, at dispersed posts in 200 ha of forest), his display site, used for at least four years, a small area in old-growth forest near centre of his home range. Courtship display involves static and inverted postures and movements of pectoral, flank and head plumes, and possibly gaping. Only nest known was a thin, rather flat structure with slight egg-cup depression, foundation of pale reddish-brown wiry grasses, lining of black wiry roots, placed in fork of thin branch between horizontal bough and trunk. Clutch 1 or 2 eggs; no information on incubation and nestling periods. Male ringed when in adult plumage lived for at least a further 9 years, and thus reached more than 15 years of age.

Not globally threatened. CITES II. Nowhere abundant; may be absent from apparently suitable areas of habitat, especially in C parts of New Guinea. Although thought not to be at any immediate risk, this species probably merits monitoring.