Scientists have described a new species of bird found only on the island of Rote in eastern Indonesia — but already the population of the bird, a honeyeater in the widespread genus Myzomela, is threatened by habitat loss as a result of rapid deforestation.
The discovery of the Rote Myzomela (Myzomela irianawidodoae), which was named after Indonesia’s first lady, Iriana Joko Widodo, involved a series of separate field studies between 1990 and 2015 by different groups of researchers, according to a paper published December 31, 2017, in the scientific journal Treubia.
The first observation of a Myzomela species on Rote in East Nusa Tenggara province — one of the many islands that comprise the Lesser Sunda Islands — was carried out by the Australian ornithologist Ron Johnstone in 1990.
The survey, however, was too brief for visual or audio recordings to be taken, and subsequent scientific publications referred to the bird species on Rote as being similar to one on Sumba, an island in the same chain about 230 kilometers (143 miles) to the west.
Nearly 20 years later, two Belgian ornithologists visited Rote for a different project in which they photographed extensively and made a long series of sound recordings of the birds they encountered there.
“Considering the fact that Sumba and Rote have a distinct biogeographical history — they were never connected to each other — it would appear unlikely that the Rote bird would be the same species as on Sumba,” Philippe Verbelen, one of the two Belgian researchers, said in an email.
“This suspicion was further strengthened when we realized how strong the vocal differences were between the song of the Rote and the Sumba Myzomela,” he added.
That led the Belgian scientists to conduct another field study in 2014, during which they performed a bioacoustic analysis comparing the responses of Sumba Myzomelas and Rote Myzomelas to playback recordings of the birds.
The result, Verbelen said, was that the song of male Rote Myzomelas failed to trigger territorial reactions from male Sumba Myzomelas, and vice versa. Meanwhile, playback experiments on both Sumba and Rote triggered strong territorial reactions when recordings of the territorial song of a male myzomela from the same island (playback of Rote recordings on Rote; playback of Sumba recordings on Sumba) were used.
“The territorial song of Myzomelas has a strong biological function. Those reactions are a strong indicator that the Myzomelas from Sumba and Rote are indeed different species,” the researchers said in a statement.
The final confirmation of a new bird species was made by scientists from the National University of Singapore and the Indonesian Institute of Sciences (LIPI) who went to Rote in December 2015 to capture four specimens of the bird.
The team made another bioacoustic analysis, and also compared the animals’ body structure with other species in the Myzomela genus, such as Buru Myzomela (Myzomela wakoloensis), Seram Myzomela (Myzomela elisabethae), Banda Myzomela (Myzomela boiei), Sulawesi Myzomela (Myzomela chloroptera), Sumba Myzomela (Myzomela dammermani), Timor Myzomela (Myzomela vulnerata), and the Red-headed Myzomela (Myzomela erythrocephala).
“The Rote Myzomela is closely related to other species of honeyeater that occur on surrounding Indonesian islands, but it has a unique song which differentiates it from all its relatives,” the statement said. They also noted several subtle and previously overlooked differences in shape and plumage, including a narrower black breast band than the Sumba birds.
The newly described bird typically inhabits the tropical woodlands on Rote, the researchers said. However, they also noted that most of the island, which is only 1,226 square kilometers (473 square miles) in size, smaller than Phoenix, Arizona, had been heavily deforested and developed for residential and agricultural use to accommodate a growing population.
“[Rote] does not have a major terrestrial protected area despite the fact that it has several endemic bird species as well as other birds with a highly restricted range — only shared with Timor and Semau [islands] for example — and certain species that are highly threatened throughout their range, such as the Olive-shouldered Parrot, the Yellow-crested Cockatoo and the Timor Green Pigeon,” Verbelen said.
In Indonesia, members of the genus Myzomela, including the Rote Myzomela, are protected under the country’s 1990 conservation law and a 1999 government regulation on wildlife. The researchers hope that naming the new species after the wife of President Joko Widodo will do even more to promote the protection of the bird.
“The fact that this bird was named after Indonesia’s first lady generated big media attention. I believe and hope this can help the general cause of forest conservation and biodiversity protection in Indonesia. It is badly needed considering the rates of forest destruction in Indonesia,” Verbelen said.
Due to these threats, the team has also suggested that the species be categorized by the IUCN as “Vulnerable,” and that follow-up surveys be made to describe the population size of the Rote Myzomela.
“If the Rote Myzomela were to vanish from Rote, I’d expect that other unique bird species such as the Rote Boobook that strongly depends on good quality forests and big trees would go extinct, too,” Verbelen said.
“The world becomes a poorer place each time we are losing a species. In general, it is important to halt biodiversity loss and prevent any species from going extinct,” he added. — Basten Gokkon
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