Growling Riflebird Ptiloris intercedens Scientific name definitions

Male 34 cm, 155–214 g; female 28 cm, 102–149 g. Male , with bright iridescent blue crown  and breast and with rest of plumage mostly matt black and variably tinged with blue, is in all respects almost identical to nominate L. magnifica (which see), but has bill on average shorter, base of culmen with more feathering, and flank plumes shorter (not extending beyond tail); iris dark brown, bill black, mouth lemon-yellow to lime-green with yellow gape-line, legs dark lead-grey to blackish. Female, quite bright orangey rufous on back, with prominent supercilium, and heavily barred black below, is likewise very similar to female L. magnifica, but has bill slightly longer with more feathering at base of culmen. Juvenile undescribed. Immature male gains adult plumage gradually, becoming blotchey with dark patches through progressive moults, presumably gaining full adult plumage in 4–5 years.

See L. paradisea for comment on generic placement. Previously considered conspecific with L. magnifica, but differs in its growling vs whistling call (4); feathered base of culmen (1); shorter elongate flank plumes (1); slightly smaller size and lighter weight (1). Monotypic.

E & SE New Guinea E from Ramu R and Astrolabe Bay in N and, in S, from Purari R.

Rainforest in lowlands, hills and lower montane zones, also monsoon forest, swamp-forest and gallery forest. Occasionally visits mangroves, and either this species or L. magnifica (identity not known) recorded also in timber plantations such as teak (Tectona) (1 Peckover, W. S. (1990). Papua New Guinea Birds of Paradise. Robert Brown and Associates, Carina, Queensland, Australia. Close ). Selectively logged forest also used, the birds preferring the taller trees and forest patches. Altitudinal range from sea-level to c. 700 m, occasionally or locally to 1740 m.

Diet consists of fruits and invertebrates. Fruits taken include those of Schefflera species, of the aroid Amorphophallus paeoniifolius, and of Elmerrillia, Chisocheton cf. weinlandii, Omalanthus novaeguineae and Gastonia spectabilis; capsular fruits significant, being nutrient-rich, with drupes and berries and figs less important in diet. Invertebrates include wide variety of insects, spiders (Araneae) and myriapods. Forages alone and in pairs, sometimes in small groups, and will join mixed-species flocks. Searches for fruits mostly in main canopy, but gleans/probes for animal items in lower canopy and subcanopy. Seems to be especially attracted to pandan trees (Pandanus), which provide both fruits and insects. Works along branches, probing, pecking at bark and investigating cavities and fern clusters, often exploring dead limbs; active, moves quickly through forest, not staying long at any one site.

Harsh, rasping, very loud growl, “hrrrak hrrrow”, first syllable rising and second one falling , is characteristic of this species and very different from the more musical and liquid whistle of L. magnifica; the second syllable (“hrrrow”) is sometimes repeated several times, and occasionally is inflected upwards.

Season little known; females carrying nest material in Jul; egg-laying recorded early Jun in Moroka area of SE New Guinea; display late wet season throughout dry season, Apr–Sept near Port Moresby. Polygynous, the promiscuous males displaying solitarily at song posts and attracting female-plumaged birds. Nest an untidy ragged cup made from sticks, supported by branches near tree-trunk; a nest with two eggs found in early 20th century was a deep cup composed of thin wire-like fibres surrounded by large dry leaves (2 Hartert, E. J. O. (1910). On the eggs of the Paradisaeidae. Novitates Zoologicae 17:484–491. Close ). Clutch 1–2 eggs; incubation and nestling periods unknown.

Not globally threatened (Least Concern). Generally common or fairly common, if somewhat local. In 2002, within Crater Mountain Wildlife Management Area, estimates at 432–650 m were 14·1 individuals/km² in primary forest, 5·7/km² in old gardens and 5·2/km² in new gardens, and figures at 651–935 m were 14·9 in primary forest, 5·8 in old gardens and none in new gardens. Near Port Moresby 6 birds/10 ha counted; in 100 ha near Kakoro minimum of seven adult males, at mean nearest-neighbour distance of 175 m (range 140–275 m). Although this species’ global population size has not been quantified, it is believed to be stable, with no evidence of any declines or substantial threats. This riflebird is not hunted for its plumes, but it is likely to suffer local declines as a result of logging and forest clearance, accompanied by the expansion of settlements as the human population grows. In addition, proposed massive oil-palm (Elaeis guineensis) plantations in the Gulf of Papua drainage would be highly detrimental to this and all other forest-dependent species.