The Australasian Treecreepers are a small family composed of 7 species in two genera (Cormobates, Climacteris). One species inhabits the mountains of New Guinea (Papuan Treecreeper Cormobates placens) and the rest are restricted to Australia. As the name suggests, this group fills the "creeper" niche in Australasia, working up the main trunks and branches of Australian woodlands. The Brown Treecreeper (left) prefers eucalyptus groves but is found in a wide variety of open woodlands in eastern and southeastern Australia. It often feeds on fallen branches and logs, bobbing its tail when resting. It, like the rest of the Australia species, has a broad orange wingstripe seen in flight.

Because of their behavior, many early taxonomies placed them near the Holarctic tree-creepers, the Spotted Creeper (Salpornis) of Africa and India, and the Philippine creepers (Rhabdornis). It is now known that they are not related to any of these birds; their tree-climbing behavior is an example of convergent evolution. They have a distinctive syndactylous foot structure, in which the "anterior digits 2 and 3 are bound together by a membrane to the end of the 1st phalanx on digit 2, and digits 3 and 4 are joined to the base of the 3rd phalanx on digit. This condition of the foretoes apparently allows them to act in concert with the hallux as the bird creeps on trunks and branches" (Sibley 1996).

It is clear that Australasian Treecreepers are part of the great Australasian radiation, but their exact position is still unclear. The initial DNA-DNA hybridization data suggests that they were most closely related to lyrebirds, scrub-birds, and bowerbirds (Sibley et al. 1984, Sibley & Ahlquist 1990). Sibley (1996) said that preliminary DNA sequencing also support these relationships. Yet, the Handbook of the Birds of the World project now lists them at the end of great corvoid radiation, along with sittellas (family Neosittidae). It is apparent that there has been contrary evidence to the initial biochemical research. Indeed, Sibley & Ahlquist (1990) expressed reservations about the placement of this family in the Menuroidea (that is, with the lyrebirds, scrub-birds et al.) and suggested further research. It may be that the HBW placement suggests uncertainty. It is now the last family in the great Australasian radiation, just before the more traditional passerine families commence with the Tits & Chickadees (Paridae). Thus, ironically, this group is again found near the creepers, rhabdornis, and nuthatches.....

Treecreepers forage on the trunks and branches as the bird ascends using only its feet (they do not use their tail as a prop, as to Holarctic tree-creepers or woodpeckers). Insects are taken from bark crevices. Some species also spend a lot of time on the ground, and ants are a primary prey. Nests of grass, feathers, and mammal fur are concealed in hollows of stumps and trees. The White-throated Treecreeper Cormobates leucophaeus (the only Cormobates in Australia; the other one is in New Guinea) breeds in solitary pairs, but at least four species of Climacteris are communal breeders: Brown, Red-browed C. erythrops, Black-tailed C. melanura, and Rufous C. rufa. One or more helpers, usually young males, aid in feeding the incubating female and the nestlings (Noske 1980, Blakers et al. 1984, Simpson & Day 1996).

Photos: The Brown Treecreeper Climacteris picumnus was photographed in Gulpa Forest, New South Wales, Australia, on 30 Dec 1997. Photo © D. Roberson, all rights reserved.

Bibliographic note

There is no family book as yet, and the Handbook of the Birds of the World has not yet reached this group, but the Australian literature that includes this family is reasonably extensive.

Literature cited:

Blakers, M., S.J.J.F. Davies, and P. N. Reilly. 1984. The Atlas of Australian Birds. Royal Australian Ornith. Union, Melbourne Univ. Press, Carlton, Victoria.

Noske, R.A. 1980. Coopertive breeding by treecreepers. Emu 80: 35-36.

Sibley, C.G. 1996. Birds of the World, on diskette, Windows version 2.0. Charles G. Sibley, Santa Rosa, CA.

Sibley, C.G., and J.E. Ahlquist. 1990. Phylogeny and Classification of Birds: A Study in Molecular Evolution. Yale Univ. Press, New Haven, CT.

Sibley, C.G., R. Schodde, and J.E. Ahlquist. 1984. The relationships of the Australo-Papuan treecreepers (Climacteridae) as indicated by DNA-DNA hybridization. Emu 84: 235-241.

Simpson, K, and N. Day. 1996. A Field Guide to the Birds of Australia, revised 5th ed. Penguin Books Australia Ltd., Ringwood, Victoria, Australia.




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