Elachura bird species
Elachura are difficult to observe as they hide in dense undergrowthPer Alstrom

A new species of bird has been discovered in the eastern region of the Himalayas and southeast China.

Named Elachura formosa by researchers, it belongs to a unique family of birds which contains no other known species. According to researchers, the Elachura males have an unusual high-pitched song, unlike those of other Asian birds.

Scientists investigating families within the Passerida group of birds also discovered the spotted wren-babbler, whose natural habitat is subtropical or tropical mountain forests.

Elachura singing
Male Elachura have a high-pitched song which is different from those of other Asian birdsC Ramki Sreenivasan/Conservation India

The study was undertaken by researchers from the Swedish University of Agricultural Sciences in Uppsala and the Chinese Academy of Sciences in Beijing. The results were published in the Royal Society Journal Biology Letters.

Professor Per Alstrom, from the University of Agricultural Sciences, told the BBC: "This single species is the only living representative of one of the earliest off-shoots within the largest group of [perching birds], which comprises [around] 36% of the world's 10,500 bird species."

Alstrom described Elachura as "extremely secretive and difficult to observe, as it usually hides in very dense tangled undergrowth in the subtropical mountain forests."

He added: "However, during the breeding season, when the males sing their characteristic, high-pitched song, which doesn't resemble any other continental Asian bird song, it can sometimes be seen sitting on a branch inside a bush."

According to Alstrom, the bird had been previously overlooked because it resembles wrens and wren-babblers.

He explained: "This similarity is apparently either due to pure chance or to convergent evolution, which may result in similar appearances in unrelated species that live in similar environments - some wren-babblers can be neighbours to the Elachura."

Researchers were able to identify the species by analysing the molecular differences in the DNA of Elachura, which revealed their evolutionary heritage. Previously, this method was used to probe evolutionary patterns in neotropical birds through DNA barcodes, which compared Argentinian birds and their patterns of genetic diversity to those of North American birds.