Wednesday, 10 October 2018

When species distribution models are validated: a case of a Hottentot Buttonquail

This was something I wrote toward the end of last year for African BirdLife magazine, but that was then never published...

We’ve come a long was regarding our state of knowledge regarding the Hottentot Buttonquail since Africa Birds&Birding published an article with one encountered in the Kouga Mountains: the Fynbos Enigma in 2013. The summary of our state of knowledge described in that article was picked up by BirdLife International, and resulted in the species being classified as Endangered. We now know a lot more about the species thanks to a biome wide survey sponsored by BirdLife South Africa, together with BirdLife Overberg, Tygerberg Birdclub and other sponsors, and involving many participants. The species was recorded in many locations, sometimes in fairly high numbers, although it was also not found on many more.

An article published recently in Ostrich showed the species was far less associated with restios than everybody thought. Moreover, species distribution modelling published in Bird Conservation International confirmed that fire age associated with the fynbos was important at predicting the species presence. The map we produced shows that the potential suitable habitat stretches quite far east, further than it has ever officially been recorded.

The location of the Hottentot Buttonquail encounters from Grahamstown are indicated by the red dot. Species distribution model for Hottentot Buttonquail, with yellow to red good probability of occurrence, and blue low probability of occurrence.

It was thus of great interest to hear anecdotal records of encounters of small, quail-like birds, descriptions of which sounded tantalizingly like buttonquail, from near to Grahamstown. While the area is more generally associated with the thicket biome, pockets of fynbos hide among the hills on many ridges or south facing slopes. Anthony Bernard, a marine scientist at the South African Institute for Aquatic Biodiversity was interested in getting some official identification after encountering two small ground birds on an evening walk. While the first bird, spotted running around a shrub, was flushed before they could note identification features, the second froze underneath the one pointer allowing Anthony time to catch the bird before it or the dog knew what was happening!

While a side or belly shot would have been needed to be conclusive that this is not Black-rumped Buttonquail, the face and eye from the photo here fit well with a Hottentot Buttonquail. Subsequent to this, Lynette Rudman and Daniel Dankwerts caught and ringed two buttonquail, confirming the presence of this species close to Grahamstown, as predicted.

Buttonquail identified as Hottentot. Photo by Anthony Bernard

For me this was vindication of our species distribution model, based on climate, habitat and various other environmental variables, but overall was a super exciting record for the Eastern Cape.

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