Four odd 'thrushes': 2The name "Sulawesi Thrush" suggests the matter of its relationships is fully resolved, but this is far from true. Hartert (1896), in erecting the genus Cataponera, while admitting its thrush-like appearance (hence "turdoides"), thought it a babbler related to Garrulax, and its black eyebrow is a notable timaliine feature (e.g. Striated Laughingthrush Garrulax striatus, Grey-throated Babbler Stachyris nigriceps, various fulvettas and parrotbills) but unknown among thrushes. Meyer & Wiglesworth (1898) commented that it is very like certain blackbirds in appearance, though the shape of its wing, as well as the peculiar superciliary stripe of black, at once shows that it has no very real near affinities with Merula or Turdus.
On the other hand Heinrich found that in both voice and juvenile plumage it was distinctly turdine, so Stresemann & Heinrich (1939-1941) placed it with the thrushes. Coates & Bishop (1997) seem to settle the matter: "Behaves like a typical thrush (Turdus)... flushes with typical thrush-like calls from the understorey". Yet recently Jon Riley commented to me (in litt.) that, on the few occasions he saw it, "it behaved very like a tree babbler or scimitar babbler: very active, restless movements, bouncing around in the lower storey"; and Richard Thomas tells me he had a similar impression during his encounter. There is, moreover, a curious single-paragraph paper by Desfayes (1967) which, while failing to consider the evidence in Stresemann & Heinrich (1939-1941), restated the case for what he called the "Black-browed Babbler": "its thick, rounded rufous tail, bill shape and general proportions are unlike any Turdinae. Its similarity to Garrulax impresses one at once... [including] a tendency of having bare orbital skin". Aaaagh! Back to the fence. The Fruithunter is one of the special wonders of Borneo, ranking alongside the outrageously weird Bristlehead Pityriasis gymnocephalus and a handful of other avian genera endemic to the island (but far fewer than Sulawesi!). The species, the most notable discovery of John Whitehead on Mt Kinabalu and named, like the Philippine Eagle Pithecophaga jefferyi, for his father, was initially considered to be a triller (Sharpe 1887), and this view, with the occasional notion that it might be an oriole, persisted for nigh on a century until Ames (1975) pointed out its turdine syringeal morphology, Ahlquist et al. (1984) found a DNA link to Turdus, and Olson (1987) noted its skeletal agreement with the thrushes and plausibly argued for its placement near (and even congeneric status with) the cochoas Cochoa. Even so, Sheldon et al. (2001) report on some strange attributes: When sitting, their posture is pigeon-like, but when they congregate at berry trees, they act much like bulbuls. They also resemble laughingthrushes in some behaviors and often occur in pairs. Their flight is that of a campephagid, in that they dip their pointed wings in and out rather than flap. Pigeon, bulbul, laughingthrush, cuckooshrike, oriole - what a bird! Even its English name is no longer quite accurate. In extreme drought conditions in May-June 1998 a number of birds around the Kinabalu Park headquarters were seen to forage amidst flowerbeds on the introduced snail Bradybaena simillaris (Smythies & Davidson 1999) - a very thrush-like thing to do.
For all its harlequin guises, the Fruithunter is the most straightforward of four enigmas here, given the convergent results of the internal morphological and biomolecular analyses to which it has been subject. And clearly there is a lesson to be learnt from it - that appearances are deceptive, and behaviours are very unstable guides to taxonomic position. It is fascinating to contemplate what similar syringeal, skeletal and chemical studies will make of the Grandala, Geomalia and Sulawesi Thrush; but this is not to exclude the possibility that intensive field study might produce new evidence to bear on all three forms. The two latter remain so baffling that one is tempted to speculate whether they, and perhaps even Malia Malia grata, are isolated relics of a group of birds that share both timaliine and turdine features, ancestral to both and long marooned on the riddlingly interesting and appallingly neglected island of Sulawesi. When is someone going to set themselves up in the highlands there and spend some serious time getting to grips with these extraordinary animals?
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