New leaf-warbler discovered in Indonesia

Rote Leaf-Warbler
The newly described Rote Leaf-Warbler. Photo by Philippe Verbelen

Researchers from Singapore and Indonesia have described an unusual new songbird species. They named it the Rote Leaf-Warbler (Phylloscopus rotiensis) after the island of Rote, where it is found. The discovery was published in the journal Scientific Reports on October 23.

Rote Island is a dry monsoon island with an area of 1,200 square kilometers (463 square miles) in eastern Indonesia. It is about 500 kilometers (310 miles) northwest of Australia. In December 2017, a bird species new to science, the Rote Myzomela, was discovered on the island.

The presence of a leaf-warbler of unknown identity on Rote was first noted in December 2004 by Colin Trainor of Charles Darwin University, Australia. In July 2009, Philippe Verbelen and Veerle Dossche, two Belgian birdwatchers, made detailed observations and obtained a series of photographs of the bird.

“Alarm bells went off when we realized how strikingly different the bill shape and the coloration of the Rote bird were compared to all other leaf-warblers,” Verbelen remembered.

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“The new species is part of a large group of Asian warblers but is unique among them due to its unusually long bill,” said Nathaniel Ng, who was involved in the description of the bird during his PhD candidature at the National University of Singapore’s Department of Biological Sciences.

He added, “This odd bill shape is likely an adaptation to Rote’s dry landscapes, given that most other Asian leaf-warblers live in humid forest.”

The scientific description was partly aided by comparisons using genome-wide data collected through Next-Generation Sequencing. “This may well be the first time – to the best of our knowledge – that a new bird species has been described partly on the basis of genome-wide DNA data,” added Elize Ng, a researcher with the Avian Evolution Lab under the NUS Department of Biological Sciences.

“This work would not have been possible without the partnership with the Indonesian Institute of Science, and in particular, with Dr Dewi Prawiradilaga,” said Assistant Professor Frank Rheindt, the leader of the study and head of the AEL under the NUS Department of Biological Sciences.

Each year, about five to 10 new bird species are described worldwide. The fact that this bird is the second novel species described from Rote in the last 12 months highlights the island’s conservation value. Rote’s natural landscapes are under grave threat, with a burgeoning human population exerting ever-increasing pressures on its monsoon woodland and savannah. These factors prompted the research team to propose the bird to be formally classified as Vulnerable by the International Union for the Conservation of Nature.

Watch a video about the discovery

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