The first endemic bird species to be recorded on the Indonesian island of Lombok, the newly described Rinjani scops owl (Otus jolandae) was interestingly discovered by two separate research groups just days apart during independent expeditions in September 2003.
“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 vocalisations of an owl that [I was] not familiar with,” said George Sangster, lead researcher from Stockholm University’s Department of Zoology.
These unique, whistling vocalisations also caught the attention of Ben King, a researcher from the Ornithology Department of the American Museum of Natural History in New York, just a matter of days later. Coincidentally, King was on a separate expedition on Lombok, an island off the east coast of Bali, to study the same nightjar species as Sangster.
“My experience was similar to George’s,” said King. “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.”
Initially, the researchers were uncertain as to whether or not the calls were being produced by a previously known species from Java and Bali, which perhaps had so far been overlooked on Lombok. However, this possibility was soon dismissed when the sound recordings of the mystery species were played back.
“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.
Due to their inquisitive and territorial nature, the owls responded strongly to the recordings and approached the researchers, giving the scientists a clear view of the birds. Initially, the Rinjani scops owl, named for its volcano home Gunung (Mountain) Rinjani, was thought to be the Moluccan scops owl, as it had a very similar appearance in terms of plumage. However, the whistles it produced were markedly different from the raven-like croak of the Moluccan scops owl.
Confirming the discovery
To verify their new discovery, the researchers conducted detailed examinations of the whistling calls, as well as thorough checks of taxonomic literature. The plumage, body measurements and DNA of the Lombok birds were carefully compared against those of a variety of museum specimens, eventually confirming the Rinjani scops owl as a distinct species.
“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, especially considering that no-one had noticed anything special about these owls in the previous 100 years,” mused Sangster.
Implications and future discoveries
The scientists are keen for future studies to be carried out to determine the exact distribution, elevational range and population density of this new owl species. While surprised at how common the Rinjani scops owl is, with the species being found at several locations and at seemingly high densities, the researchers are particularly interested in finding out whether it occurs throughout the lowland forests where much habitat destruction has occurred.
This latest discovery has highlighted the possibility that there could be further undiscovered bird species in Indonesia yet to be found and described.
“In the past, ornithologists and birdwatchers have largely ignored the island because, unlike Java, Bali, Flores and other islands in the region, no bird species were unique to it,” said Sangster. “Our 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.”
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Kathryn Pintus, ARKive Text Author