Stone-curlew to be split?
A genetic study of the four recognised subspecies of Stone-curlew has found the current classification inaccurate, and that the two forms on the Canary Islands may be a separate species.
Six populations were sampled from the ranges of the four subspecies, and after mitochondrial and nuclear genes were assessed, the current subspecific taxonomy was found to be untenable.
The unique genes of the two Canaries forms – Burhinus oedicnemus distinctus and B o insularum – suggest that they comprise one poorly differentiated Macaronesian species, but more work is needed to fully ascertain their status. Contrarily, the European nominate and desert saharae subspecies were found to have no differentiation, and to probably be clinal in their differences. Nominate and saharae appear to share wintering grounds, and this distribution may partially represent Gloger's Rule, in which plumages get darker the further to the north the bird is found; darker plumage is believed to be more resistant to humidity and bacteria, whereas lighter plumage enables camouflage in the desert landscape.