Century-old debate on its relationship with other owlets resolved

Between four and six million years ago, long before humans evolved, drastic climatic changes in the Indian subcontinent led to the evolution of a new bird: central India’s now-endangered and rare forest owlet. Scientists have also found that it belongs to the same genus as the commonly-seen spotted owlet, finally settling a century-old debate on its genetic relationship with other Indian owlets.

The taxonomy of the forest owlet (Heteroglaux blewetti), which resembles the spotted owlet Athene brama, has always been a mystery. Taxonomists placed it in a separate genus Heteroglaux and sometimes in Athene; others saw it as more closely related to another species, the jungle owlet.

For the first time, a team of scientists obtained permits to carefully take some feathers from forest, spotted and jungle owlets in the states of Madhya Pradesh, Maharashtra, Gujarat and Chhattisgarh. From the feathers, they extracted DNA (of five genes, both mitochondrial and nuclear) and built a genetic tree to reveal the relationship between the birds. Their results show that the forest owlet belongs to the same genus (Athene) as the spotted owlet, thus settling a century-old debate about its taxonomy. According to their paper published in PLoS ONE, the bird can now be known as Athene blewetti.

Fossil records

Using dated fossil records of ancient owls on this genetic tree, the team estimated the time at which the forest owlet diverged from its nearest relatives, the process by which new species evolve. Their results show that the forest and spotted owlets split as different species between 4.3 and 5.7 million years ago, when drastic climatic changes occurred in the Indian subcontinent.

“Multiple cycles of wet and dry climes characterised the Indian subcontinent then,” says lead author Pankaj Koparde (Salim Ali Centre for Ornithology and Natural History). “Independent research shows that this period, the Plio-Pleistocene, also saw the speciation of several other high-altitude birds in the Western Ghats.”

This means that climate played a major role in the speciation of the owlets, says Koparde. With climate change being a concern now, it would be important to study how new weather events affect the forest owlet, he adds.

This would be crucial to conserve the species, which is rare and found in a severely fragmented habitat threatened by the activities of humans, a species that came into being a few million years after they did.