Of late, several new species have been discovered in Arunachal Pradesh, a mysterious, magical and mystical land tucked away in the north eastern tip of India.

And now the latest one being a new bird species – the Himalayan Forest Thrush – the fourth new species of bird to be discovered in Arunachal Pradesh, reports C K Duworah, a conservationist  working in NE India.

A team of scientists from India, Sweden, China, the US and Russia described the Himalayan Forest Thrush from the northeastern India and adjacent parts of China.

Dr Per Alström of Uppsala University, Sweden, and the team discovered the species they were studying birds at different elevations in the mountains of western Arunachal Pradesh.

Ironically, it was the tuneful birdsong that led to the discovery of the country’s first new bird species in a decade and the fourth since independence in 1947.

Scientists named the new species as Zoothera salimalii, in honour of the late Indian ornithologist Dr Salim Ali.

According to Dr Pamela Rasmussen, of Michigan State University, “the discovery process for the Himalayan forest thrush began in 2009 when it was realized that what was considered one species, the plain-backed thrush (Zoothera mollissima), was in fact two different species.”

Further analyses of plumage, structure, song, DNA and ecology from throughout the range of the “Plain-backed Thrush” revealed that a third species was present in central China. While this population was already known, it was treated as a subspecies of “Plain-backed Thrush”. The scientists have instead called it Sichuan Forest Thrush. The song of the Sichuan Forest Thrush was found to be even more musical than the song of the Himalayan Forest Thrush.

DNA analyses suggested that these three species have been genetically separated for several million years. Genetic data from three old museum specimens indicated the presence of a fourth species from China that remains unnamed. Future field studies are required to confirm this.
The Himalayan Forest Thrush is locally common. It has been overlooked until now because of its close similarity in appearance to the Alpine Thrush.

Since 2000, an average of five new species per year have been discovered globally, a significant numbers are from NE India or East Himalayan region. But rampant deforestation might pushed some species towards extinction before discovering, Duworah said

It is said that the plain-backed thrush in the coniferous and mixed forest caught scientists’ attention as it had a rather musical song, as birds found in the same area had a much harsher, unmusical song.

“We realized that the two different song types from plain-backed thrushes that we first heard in northeast India in 2009, and which were associated with different habitats at different elevations, were given by two different species,” said Dr Alström, who led the group.

Later investigations revealed both physical and genetic differences between birds from these two populations.

The study describing the new species has been published online in the journal Avian Research.

by Pranab Sarma