others more orange, but each mountaintop population has a different song style and genetic fingerprint. Speciation is happening through separation not just on oceanic islands, but these sky islands, too.

This research led by V.V. Robin at the Indian Institute of Science Education and Research showed that what was previously thought to be one species of shortwing is really three, each unique to its own mountaintop.

A parallel finding was discovered with birds called laughingthrushes—and it is likely other singular species of mammals, birds, and reptiles in the region will be divided into many more.

"New species continue to be discovered in these mountains, with over a dozen frog species, about three plant species and two new bird genera, and one bird species described just in 2017," says Robin. (Read aboutseven new M&M-sized frog species found in the Western Ghats.)

Preserve and Protect

The legacy of this separation between populations of one species that over time became multiple is due to a glaciation event around four million years ago. Aridity caused by glaciation drove species, including shortwings and laughingthrushes, higher up the mountains for suitable habitat.

"Understanding the evolutionary past of these sky islands also helps us to better prioritize areas that we should conserve for the future," says Uma Ramakrishnan, a molecular ecologist at the National Centre for Biological Sciences in Bangalore who was involved in the bird speciation research.

When the glaciers receded and the climate changed, the animals and plants all stayed confined to their preferred locations—confined to separate sky islands. Examining the differences in the color, shape, and