Orange-billed lorikeet

The orange-billed lorikeet was originally formally described as a species by the German ornithologist Ernst Hartert in 1896 based on specimens from the "Victoria district" in the Owen Stanley Range in New Guinea.[3] The generic name Neopsittacus is from the Greek νεος (neos), meaning new, and ψιττακος (psittakos), meaning parrot. The specific epithet pullicauda is from the Latin pullus, meaning dark-colored, and cauda, meaning tail.[4] Alternative common names for the species include emerald lorikeet, alpine lorikeet and orange-billed mountain lorikeet.[2][5]

The species shows clinal variation, with birds from western populations being smaller and paler than birds from southeastern ones.[2] It is treated as having one subspecies by the International Ornithologists' Union;[6] however, some authorities recognize as many as three subspecies on the basis of differences in appearance, with populations from central western New Guinea separated as N. p. alpinus[lower-alpha 1] and populations from northeastern New Guinea separated as N. p. socialis.[lower-alpha 2][7]

The orange-billed lorikeet is one of two species in the genus Neopsittacus. It and the yellow-billed lorikeet are basal within a clade (group of organisms descending from a common ancestor) formed by Neopsittacus, Lorius, Psitteuteles, Parvipsitta, Pseudeos, Chalcopsitta, Glossoptilus, Glossopsitta, Saudareos, Eos, and Trichoglossus.[8][9]

The orange-billed lorikeet is a small species of lorikeet, with a length of around 18 cm (7.1 in) and a weight of 25–40 g (0.88–1.41 oz).[7] Adults are mainly dark emerald green, with red underparts and narrow yellow streaking on the cheeks.[7][10] The flanks and wings are also emerald green; the underside of the tail is a duller green, with a red patch at the base. The underwing is bright red and is especially prominent in flight.[10] The iris and beak are orange, with a yellow tip to the latter, and the feet are dark grey.[5] Immatures are duller in color, with less red on their underparts and an orangish-brown bill.[7] Fledglings have yellow beaks, which turn orange at around 6 months of age.[11]

Other than the yellow-billed lorikeet, no other parrot in the species's range has similar coloration.[10] Compared with the yellow-billed lorikeet, it is smaller in size, has more richly coloured plumage, and has a smaller, orange bill.[5] Additionally, it can also be distinguished by its flanks and wings being the same shade of green, the underside of the tail being dull green with red at the base, and the lack of an olive tint to the top of its head.[10]

The orange-billed lorikeet is endemic to the island of New Guinea. It inhabits forest canopy, forest edges, and cleared areas bordering forests at high elevations in mountains in the Central Range and the Huon Peninsula, but is absent from the Bird's Head Peninsula. It prefers cloud forest at elevations of 2,100–3,800 m (6,900–12,500 ft), but has been recorded at elevations as low as 800 m (2,600 ft).[2][7] Vagrancy at lower elevations suggests that the species may sporadically migrate attitudinally;[7] Neopsittacus is one of only five genera in the order Psittaciformes to evolve to be nomadic.[12] At lower elevations, it often inhabits the same areas as the yellow-billed lorikeet.[2]

Orange-billed lorikeets are typically found in small flocks.[10] They feed on pollen, nectar, flowers, fruits and uncommonly, seeds. Plants it is known to feed upon include the seed cones of Papuacedrus papuanus and the berries of Sericolea pullei. It is more nectarivorous than the yellow-billed lorikeet.[7] They sometimes forage together with yellow-billed lorikeets at fruiting trees, but are rarely found with species of other genera.[10] Its breeding season is in October. It nests in hollows in tall trees, where it lays clutches of 2 eggs.[7] The orange-billed lorikeet is parasitised by a variety of insects, including the rhinonyssid mite Mesonyssus alisteri,[13] the philopterid chewing louse Psittaconirmus zinki,[14] the menoponid chewing louse Eomenopon semilunare,[15] and the rhinonyssid mite Tinaminyssus trichoglossi.[16]

The species is listed as being of least concern on the IUCN Red List due to its large range and lack of severe declines in its population.[1] It is listed on Appendix II of CITES. It is common throughout most of its range and is not particularly threatened by habitat loss or the wildlife trade.[7]