Birdwatchers called six small birds in the Western Ghats by the wrong names for more than a century. What they called laughingthrushes were not laughingthrushes and shortwings were not shortwings. A recent paper unravels who these birds’ relatives are and how they evolved. Such discoveries are rare because birds are well-studied, and their classification holds no surprises. Until now.
The erstwhile laughingthrushes and shortwings live in high-altitude cold, wet forests. Above an elevation of 1,500 metres, stunted evergreen trees grow in valleys surrounded by a sea of grassland. Called sky islands, these shola forests are as isolated from one another as sea islands. And this splendid separation spawns a diversity of species not only in frogs, lizards and snakes but also in birds that are found nowhere else. V.V. Robin, from the National Centre for Biological Sciences (NCBS), Bengaluru, and the Indian Institute of Science Education and Research, Tirupati, has studied shortwings for 15 years.
In 2002, he figured out what kind of forests the white-bellied shortwing favoured. Although he spent more time in the lowland rainforests, he found many more of these little blue birds in the sholas. The 40-kilometre-wide Palghat Gap is an insurmountable barrier for many species of birds, reptiles and mammals. On either side of this break in the hill ranges live two subspecies of the white-bellied shortwing. By analysing differences in the songs of the two populations, Robin concluded they were two species. But nagging questions about other inconsistencies drove him to investigate further.-read more
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