On a recent visit to Manus, 11 - 14 May 1989, three types of swiftlet Collocalia spp with white rumps were observed, where only two had previously been recorded (Coates 1985). These were identified as follows.
1) The commonest swiftlet was small with narrow pointed wings and a pointed tail. It had dark brown upperparts except for a neat, small, oblong (broader across the body than along it) white rump. The underparts were paler brown and a bit smudgy on the belly. This was identified as White-rumped Swiftlet C. spodiopygia, a species I had previously seen on New Britain and Bougainville. On Manus it was recorded in all habitats visited, from Lorengau at sea-level to rain forest at 200 m. It was the most numerous bird I recorded.
2) This type was similar in size and shape to the White-rumped Swiftlet and also with a small, neat white rump. This was distinguished by a glossy sheen on the upperparts (not always discernible) and a clean white belly sharply demarcated from a darker breast, which I find is a more reliable field characteristic than glossiness. This was identified as a white rumped form of Glossy Swiftlet C. esculenta, probably stresemanni. It was much less numerous than White-rumped Swiftlet and seemed to favour valleys with running water through forest or secondary growth.
3) The third form was larger than the preceding two, having a stockier body, broader wings and a square tail. Its upperparts were dark brown with a large, square, smudgy, ill-defined white rump. The belly was smudgy brown on a dirty white background, becoming more uniform on the breast. It was regularly recorded in small numbers along ridge tops in the interior of the island and always associated with White-rumped Swiftlets.
In shape and size it closely resembled Uniform Swiftlet C. vanikorensis, which has been recorded on Manus, although I did not see it on this trip. Four very similar swiftlets have been recorded in PNG, although two of these, Mountain Swiftlet C. hirundinacea and Three-toed Swiftlet C. papuensis, are endemic to mainland New Guinea (Beehler et al. 1986, Coates 1985). Both Uniform Swiftlet and Whitehead's Swiftlet have ranges extending north of Papua New Guinea (Beehler et al. 1986) although only Whitehead's Swiftlet has a white-rumped form, the New Ireland subspecies, leletensis. This subspecies is known only from a single specimen from the Lelet plateau, New Ireland (Coates 1985).
I think this third type of swiftlet I observed on Manus may be Whitehead's Swiftlet of the New Ireland subspecies. This would extend this subspecies' range 250 km westwards and would be a new species for Manus. However swiftlets are not the easiest species to identify in the field. These observations are presented in the hope that subsequent bird watchers will carefully observe the swiftlets on Manus and either confirm or refute my identification.
Beehler, B.M., T.K. Pratt & D.A. Zimmerman. 1986. Birds of New Guinea. Princeton University Press.
Coates, B.J. 1985. The Birds of Papua New Guinea. Vol 1. Dove Publications.
1) The commonest swiftlet was small with narrow pointed wings and a pointed tail. It had dark brown upperparts except for a neat, small, oblong (broader across the body than along it) white rump. The underparts were paler brown and a bit smudgy on the belly. This was identified as White-rumped Swiftlet C. spodiopygia, a species I had previously seen on New Britain and Bougainville. On Manus it was recorded in all habitats visited, from Lorengau at sea-level to rain forest at 200 m. It was the most numerous bird I recorded.
2) This type was similar in size and shape to the White-rumped Swiftlet and also with a small, neat white rump. This was distinguished by a glossy sheen on the upperparts (not always discernible) and a clean white belly sharply demarcated from a darker breast, which I find is a more reliable field characteristic than glossiness. This was identified as a white rumped form of Glossy Swiftlet C. esculenta, probably stresemanni. It was much less numerous than White-rumped Swiftlet and seemed to favour valleys with running water through forest or secondary growth.
3) The third form was larger than the preceding two, having a stockier body, broader wings and a square tail. Its upperparts were dark brown with a large, square, smudgy, ill-defined white rump. The belly was smudgy brown on a dirty white background, becoming more uniform on the breast. It was regularly recorded in small numbers along ridge tops in the interior of the island and always associated with White-rumped Swiftlets.
In shape and size it closely resembled Uniform Swiftlet C. vanikorensis, which has been recorded on Manus, although I did not see it on this trip. Four very similar swiftlets have been recorded in PNG, although two of these, Mountain Swiftlet C. hirundinacea and Three-toed Swiftlet C. papuensis, are endemic to mainland New Guinea (Beehler et al. 1986, Coates 1985). Both Uniform Swiftlet and Whitehead's Swiftlet have ranges extending north of Papua New Guinea (Beehler et al. 1986) although only Whitehead's Swiftlet has a white-rumped form, the New Ireland subspecies, leletensis. This subspecies is known only from a single specimen from the Lelet plateau, New Ireland (Coates 1985).
I think this third type of swiftlet I observed on Manus may be Whitehead's Swiftlet of the New Ireland subspecies. This would extend this subspecies' range 250 km westwards and would be a new species for Manus. However swiftlets are not the easiest species to identify in the field. These observations are presented in the hope that subsequent bird watchers will carefully observe the swiftlets on Manus and either confirm or refute my identification.
Beehler, B.M., T.K. Pratt & D.A. Zimmerman. 1986. Birds of New Guinea. Princeton University Press.
Coates, B.J. 1985. The Birds of Papua New Guinea. Vol 1. Dove Publications.
Originally published in MURUK 5(2):64
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