Rail-babbler: In search of a family

posted in: Species | 3

“The Rail-babbler (Eupetes macrocerus) is one of the most cryptic and enigmatic of the birds in the Sundaic rainforest. It occurs on the Malay Peninsula as well as in parts of Sumatra and northern Borneo. The habitat is lowland rainforest, mainly primary forest but also adjacent mature logged forest with a closed canopy.

“But what kind of bird is it? The name indicates some relationship to the rails, Rallidae, but that is obviously coincidental for this Passerine. For many years it was included in Timaliidae with the babblers, a diverse family with 309 species worldwide. However, anyone who has ever seen a Rail-babblers (or a Malaysian Rail-Babblers as it was known then) would agree that there was something wrong with this, it simply didn’t belong. The morphology doesn’t match. And nor does the ecology, a Rail-babbler can fly, but it rarely does, it prefers to walk. It walks with its fairly long legs and long tail across the forest floor cluttered with leaves and saplings, it hates to be out in the open and trots quickly across clear patches; when it reaches a fallen log it jumps up and walks across it. Even when captured and released it will immediately jump down onto the forest floor and run off (Wells, 2007).

“In 1998 I was in the Arfak Mountains in West Papua, the Indonesian part of New Guinea to photograph birds. There I came across a Chestnut-backed Jewel-babbler on the forest floor, and it struck me immediately how much this Australasian bird resembled ‘our’ Rail-babbler in built and behaviour. Craig Robson’s A Field Guide to the Birds of South-east Asia came out in 2000 and put the Rail-babbler in the crow family, Corvidae, this taxonomy didn’t make sense and was never generally accepted outside the Oriental region. David Wells (The Birds of the Thai-Malay Peninsula Volume Two, 2007) put Rail-babbler in its own family, Eupetidae, which quite possibly is the best solution. Then Handbook of the Birds of the World Volume 12, arriving in Asia this year, finally placed Rail-babbler with the family jewel-babblers and allies, now named Eupetidae after the Rail-babbler, the only species occurring in South-east Asia, the other 17 all in New Guinea or Australia. The Rail-babbler has found a suitable family at last.

babblerr-mortenstrange.jpg

“This is the picture illustrating the Rail-babbler in the book (above). I hired R Subaraj to guide me into the Panti Forest Reserve in Johor. Subaraj managed to call the bird forward by imitating its long, wailing whistle and on the third morning we finally saw it well enough to get a picture.”

Earlier, Richard Hale read the report and sent this query: “…but surely the article means the Rail Babbler has never heard of the Wallace Line? Or are there others in Borneo?”

To this, Morten Strange replies: “…no there are no other jewel-babblers on Borneo, or in Wallacea for that matter, the Rail-babbler’s nearest relatives are on New Guinea.

“This way, the Rail-babbler appears to be one of those birds that we have in South-east Asia that is the sole representative of its family in this sub region, from an otherwise exclusive Australasian family. The other examples that come to mind are of course Golden-bellied Gerygone (Our ‘Flyeater’ of the Acanthizidae family, one species in SE Asia, 62 in Australasia) and Mangrove Whistler (Pachycephalidae, one species in SE Asia, 55 in Australasia). But you may ask then, why does the Flyeater not occur on Borneo when it is in SE Asia plus Sulawesi and Lesser Sundas (across the Wallace Line in the Wallacea subregion) ..????.

“Getting back to the Rail-babbler, I did shorten the whole story a bit to get to the conclusion quickly. If you read the opening chapter for Eupetidae in HBW you will see that they consider that it might be best placed in its own family (as Wells does). However, they also point out a number of associations with logrunners and with the African groups rock-jumbers (under Timaliidae) and the small family picathartes, also restricted to Africa, which biogeographically appears even more bizarre. I jump straight to the conclusion that they end up putting it with the jewel-babblers and allies, in fact the Rail-babbler has previously been placed in the same genus as the four Ptilorrhoa jewel-babblers on New Guinea, and although it no longer is, I mention anecdotally that the similarities are striking.

“How it happened I don’t know, but we ended up with this peculiar rainforest bird right at our doorstep that is so enigmatic and unique, so I thought that it was worth mentioning.”

Morten Strange
Singapore
February 2008

Note: The Rail-babbler does not occur in Singapore, but in the nearby state of Johor in Malaysia.

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3 Responses

  1. Just a minor or you can say correction, latest research published has actually placed the Rail-Babbler nearest to the remarkable Rockfowls and Rockjumpers of tropical Africa. So the nearest relatives cannot be said to be australasian any more, but truly african.

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  2. just missed out the reference.
    Jønsson, K.A. et al. (2007). Biology Letters 3: 323- 326.

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  3. […] The problematic taxonomy of the Rail-babbler can be found HERE. […]

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