Field identification and status of the sunbird asities of Madagascar: 1

by Frank Hawkins, Roger Safford, Will Duckworth and Mike Evans, from Bulletin of the African Bird Club, volume 4.1, March 1997.

Summary
The genus Neodrepanis is endemic to the eastern rainforests of Madagascar, and is now considered to belong in the subfamily Philepittidae (asities) of the family Eurylaimidae (broadbills). It comprises two species, Common Sunbird Asity, N. coruscans, and Yellow-bellied Sunbird Asity, N. hypoxantha. The two species are best distinguished by differences in plumage (especially for males in breeding plumage) and calls. The eye-wattles, or caruncles, also differ. Common Sunbird Asity is generally common in lower montane forest and is known from many sites. Yellow-bellied Sunbird Asity occurs at higher altitudes, typically in upper, or sclerophyllous, montane forest. It is locally common where its habitat survives, but suitable sites are widely scattered, so that the distribution of the species is highly fragmented. Little is known of the ecology of either species.

Introduction and history
Amongst the ornithological wonders of Madagascar is a genus of sunbird-like nectarivores, the sunbird asities Neodrepanis. Visitors to the island are often impressed by the beauty of the easily seen species, Common Sunbird Asity, but as the plates show, it looks almost dingy compared to the luminous brilliance of its much rarer congener, which is surely one of the world's most stunning birds.

Common Sunbird Asity was described in 1875 and considered to be a sunbird (Nectariniidae). A second species, Yellow-bellied Sunbird Asity, was described in 1933 from museum skins (16), having at the time never been knowingly observed in the field. Taxonomic review later showed that Neodrepanis is not a sunbird genus, but is closely related to another peculiar Malagasy endemic genus, the asities Philepitta (1). The two genera formed the family Philepittidae. However, further studies have provided strong evidence that they should be considered a subfamily, Philepittinae, of the heterogeneous broadbill family, Eurylaimidae (14). Not surprisingly given this history, various names have been suggested for the species of Neodrepanis. Their English generic name derives from the Malagasy name for the Philepitta species, while the scientific name draws attention to convergence with the Hawaiian honeycreepers (Drepanidini).

Many people know N. coruscans as either as Wattled Sunbird Asity, or merely Sunbird Asity, and N. hypoxantha as Yellow-bellied Sunbird Asity, even though both species have wattles and yellow bellies! Here, we follow Lambert, who coined the sensible name Common Sunbird Asity for the former (11).

In the absence of field observations of Yellow-bellied Sunbird Asities, understanding of its status and field characters was for long based on only 13 old museum skins, none of which was supported by precise data on locality or altitude. However, clarification is now at hand, because the species has been observed frequently in recent years as more of the island's remote rainforests have been explored. We have seen and, in some cases trapped, this species at five sites since 1988; these records form the major basis of this review. Lambert and Woodcock give much information from an earlier version of this paper (11). Here, we emphasise and elaborate certain details, and include the first published photographs and sonograms for either species.

Identification
The genus Neodrepanis is characterised by a tiny body with a short tail, a fine, strongly decurved bill and, during the breeding season, strong sexual dichromatism. Males in breeding plumage are brilliant blue and black above and variably bright yellow below, with extraordinary blue and green facial caruncles. Females, males in non-breeding plumage and immatures are dull blue-green above, lack caruncles and are variably yellowish below; some female-plumaged birds (at least for Common Sunbird Asity) have a half-sized caruncle and may be immature males. In winter, males are often seen with traces of breeding plumage coloration.

Males are easy to identify in breeding plumage. Male Common Sunbird Asities are duller than Yellow-bellied in almost all respects. The former have brilliant royal blue-fringed back crown, nape, mantle and scapular feathers, and narrow but fairly conspicuous yellow fringes to the secondaries and greater and median wing coverts. Their underparts are dull, deep yellow, with strong olive-brown streaking in the centre of the breast; the flanks, belly and undertail coverts are unstreaked and somewhat brighter. The caruncle is almost square and turquoise-blue, rather greener around the eye. It extends only a short distance in front of the eye, and is not connected to the area of blue (basally) and green (distally) bare skin that overlies the basal quarter of the bill.

Male Yellow-bellied Sunbird Asity (Frank Hawkins)

Male Yellow-bellied Sunbird Asities in breeding plumage have the crown, nape, mantle and scapular feathers all black, widely edged brilliant royal-blue. The wing feathers lack the yellow fringes shown by Common Sunbird Asity. The underparts are an intense buttercup yellow. The caruncle is larger and more corrugated than that of the Common Sunbird Asity, extending as far in front of the eye as behind, and joining (aside from a few bristly feathers on the lores) with the extensive blue (basally) and green (distally) bare skin on the basal half of the bill; it also projects further upwards, sometimes compressing the crown feathers into a kind of Mohican-style crest. It is royal blue around the edges, with turquoise spots on the elevated parts (notably on the lower margin, where the corrugations suggest a series of brilliant blue spots under the eye) and bright lime green in the middle.