February 14, 2013
New Owl Species Discovered In Indonesia By Its Unique Whistle
Lawrence LeBlond for redOrbit.com - Your Universe Online
A new species of owl has been discovered in Lombok, Indonesia by two researchers just a few days apart from one another in early September 2003. But it was not the plumage that gave this bird away. The unique night song of the Rinjani Scops owl (Otus jolandae) caught the attention of these two scientists, offering evidence that the island of Lombok has its first recorded endemic bird species.
Nearly a decade later, the first detailed description and naming of this species has been published in the open access journal PLoS ONE by an international team of scientists led by George Sangster of the Swedish Museum of Natural History.
The Rinjani Scops owl had long been confused with a more widespread owl species because of its similar plumage. However, George Sangster and a colleague, Ben King of the American Museum of Natural History (AMNH) in New York, found evidence on two separate occasions in September 2003 that this owl may have been a new species based on its unique call.
"I found the new owl on 3 September 2003," said Sangster, describing the encounters in a BBC Nature interview. "I was on Lombok to collect sound recordings of the local population of a species of nightjar. On the first night I arrived on Lombok, we heard the vocalizations of an owl that [I was] not familiar with."
Coincidentally, King was in Lombok at the same time, recording the sounds from the same nightjar species, when he made his audible discovery on 7 September 2003. Interestingly, the two researchers had never met before this and had been working separately.
"My experience was similar to George's. While I was tape-recording the nightjar, I heard a song that sounded like an owl, but unlike any I'd heard in years of field work in Indonesia," explained King.
"It was quite a coincidence that two of us identified this new bird species on different parts of the same island, within a few days of being on the island. That is quite a coincidence, especially considering that no-one had noticed anything special about these owls in the previous 100 years," Sangster commented.
Sangster initially doubted what he captured was in fact a unique owl species to Lombok, and surmised that the sounds were from a previously known species that is also found on Java and Bali that for some reason had been overlooked on Lombok.
But this explanation was quickly overruled when he played the sounds back on his recorder.
"When we first heard them, the owls were very vocal, and either involved in a duet (of male and female) or a duel (between two males). Because we were not sure which species this was, we made recordings and played it back. Owls are territorial, so when their sound is played back in their territory, the owl usually comes to investigate the 'intruder'," explained Sangster.
When playing back the recording, the owls responded strongly and approached the researchers, giving the team a clear view of the owls. This confirmed that the vocalizations did in fact come from this particular owl, a crucial piece of evidence, according to the researchers.
The Rinjani Scops owl looked very similar to the Moluccan Scops owl, which had been previously reported on Lombok. However, the whistles of the new species sounded completely different from the “raven-like croak” of the Moluccan Scops variety.
And the researchers had only realized that this was in fact a new species after checking taxonomic records in literature and examining the sounds more closely.
To further verify the species as a new discovery, the researchers studied plumage differences in museums around the world and took measurements of various body parts. They then used playback in the field to determine which species are present on Lombok and Sumbawa, before using DNA data to compare all relevant species.
The team surveyed locals on Sumbawa, to which they discovered the sounds were unfamiliar to them.
"With one exception, none of the locals recognized the songs from playback of recordings made on Lombok except for one man, but he was an immigrant from Lombok who knew the song only from Lombok and had never heard it on Sumbawa," said the researchers.
So based on all their work, the researchers came to the conclusion that this was in fact a new species from Lombok, the first endemic bird species of the island.
The naming of the species, O. jolandae, comes in honor of the wife of one of the researchers who co-discovered the species. The common name, Rinjani, is named after Gunung Rinjani, a volcano on Lombok that is the second highest volcano in Indonesia.
Sangster said that this discovery gives scientists hope that more undiscovered bird species may be hiding in the jungles of Indonesia.
"Several species have already been announced in the scientific literature but await formal description. There are probably several other species of Scops owls in Indonesia that remain overlooked, even if they are already named,” he told BBC Nature.
“Until recently, many species of owls were included as 'subspecies' of highly variable, widespread species. Step-by-step, we are learning that this is not always correct, and that some of those are better considered as species,” he noted.
What was perhaps most surprising to Sangster, was how common this new species was. After making the initial discovery, researchers found the owls at several other locations and often heard multiple individuals calling from different directions.
If one thing is certain, Sangster noted, the “study underscores that even after 150 years of scientific study we still do not know all birds in the Indo-Malayan region. In fact, Indonesia is a treasure trove for taxonomists."
Listen to more calls of the Rinjani Scops owl in the PloS ONE article.