- 02.13.13
After hiding in plain sight for more than a century, a small Indonesian owl has finally been revealed for what it is: a previously unrecognized species in the genus Otus, betrayed not by its appearance but by its song.
The newly named Otus jolandae, a scops owl, lives on Lombok island and resembles the owls living on the islands next door. But O. jolandae doesn’t sing the same tune as its neighbor, Otus magicus. The owl’s nocturnal whistling call suggested that the bird living in the foothills of Indonesia’s second-tallest volcano was actually a different species, researchers report today in PLoS ONE.
“Scops owls are small, nocturnal forest inhabitants, whose presence in an area is very easily missed unless they are calling,” said Per Alstrom, a taxonomist at the Swedish University of Agricultural Sciences, who was not a member of the owl-finding team. “The authors have done very thorough analyses of both morphology and vocalizations, and found the new scops owl to be significantly different from all other known species.”
The owl had been lumped in with O. magicus since at least 1896; that was when British naturalist Alfred Everett, a civil servant who had been stationed in Borneo, collected several of the birds and sent the specimens to museums.
For more than a hundred years, the owl’s true identity was a mystery — until 2003, when taxonomistGeorge Sangster and his wife Jolanda were visiting Lombok’s forests. Sangster, a graduate student at Sweden’s Stockholm University, was there to record the songs of a different bird, the nightjar.
“On the very first night, just a few hours after my wife and I arrived on Lombok, we heard the vocalizations of an owl that we were not familiar with,” Sangster said. “Initially, we thought it was perhaps a previously known species from Java and Bali, that for some reason had been overlooked on Lombok.”
Sangster recorded the owl and played its songs into the forest. When the owls approached, he saw that they looked nothing like the owls on Java or Bali. Instead, they resembled O. magicus, which lives on the islands to Lombok’s east.
But something was wrong.
“Its whistle sounded completely different from the raven-like croak of that species,” Sangster recalled. “At home, I learned that no one had given a name yet to the scops owls on Lombok, which was the first time I realized that this might indeed be an entirely new species.”
Otus jolandae
Otus magicus albiventris
Independently, a few days later, Ben King, a study coauthor and research associate at the American Museum of Natural History, also recorded the owl. Additional recordings from various spots on the island captured the same strange song, a tune familiar to Lombok residents. But people living on nearby islands had never heard it — instead, they were familiar with the barking owl call. When Sangster’s colleague, Philippe Verbelen, went looking for the whistling owl on nearby islands in 2008, he came up empty. And the whistling owl was the only scops owl found on Lombok.
“This suggested that only one species occurs on each island,” Sangster said.
When the team compared the new owl with museum specimens — such as those Everett had collected — to O. magicus, they found only very subtle differences in color on the back, breast, and belly. That makes sense, said Niels Krabbe, an ornithologist at the University of Copenhagen. Owls in the genusOtus “communicate vocally and have rarely evolved plumage characteristics for signalling. Their plumage coloration seems to serve no other purpose than camouflage,” Krabbe said.
The results of DNA sequencing, which Sangster intends to publish later this year, also confirm that O. jolandae is a different species.
Now, the team thinks there are two types of owl living on Lombok: the new species, which Sangster named after his wife, and a type of barn owl.
Identifying birds based on behavior — and not just appearances or genetics — is helping taxonomists undo much of the lumping together of species that occurred in the past. “We’re realizing there’s a lot more diversity in plants and animals than we might have expected, just based on their physical appearance,” said Wesley Hochachka, an ornithologist at Cornell University’s Lab of Ornithology said. “There’s a fairly time-honored tradition in accepting that, at least as the first line of evidence, differences in vocal behavior are good markers of differences in species.”
(Recordings: George Sangster)
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