Asian Scientist (Sep. 11, 2013) – Researchers have discovered a new ground-dwelling forest bird species that lives on Luzon Island of the Philippine archipelago.
The new species, dubbed the Sierra Madre Ground-Warbler, is described in a paper published in The Condor, a scientific journal of the Cooper Ornithological Society.
“The ground-warblers are very unique birds,” said Pete Hosner, who co-authored the study.
“They’re only known from the northern Philippines, and they have no close relatives. As the name suggests, they’re ground-walking songbirds—rotund, with strong legs and weak wings—and it appears that they can barely fly.”
“They tend to inhabit dense forest understory, where they feed on insects. Their song is extremely high in pitch, and ventriloquial—it’s almost impossible to locate the source of the sound in the forest—they always sound like they are far away, even when they are almost at your feet.”
Hosner said the new species of ground-warbler looks similar to the other two species of ground-warblers in the Philippines, so it wasn’t recognized as an independent species at first.
“The three species of ground-warblers now recognized are essentially identical in size, shape and juvenile plumage coloration held in their first year of life, but they differ from one another in adult plumage coloration,” he said.
According to Hosner, the reason that this new species remained undescribed for so long was that the adult plumage of the very first ground-warbler to be described was unknown.
That species, Cordilleran Ground-Warbler, was documented only from a single juvenile until our recent fieldwork.
As a result, the ‘discovery moment’ was when the researchers saw an adult individual of the known species.
Examination of its DNA was key to differentiating the new ground-warbler once it was spotted in the field.
“When we noted the different plumage coloration between adult birds in the Cordillera and the Sierra Madre in northern Luzon, we sequenced DNA to determine if the plumage differences were individual variation within a species, or if the two plumage forms were also genetically diagnosable,” Hosner said.
Through this analysis, the researchers found that Cordillera and Sierra Madre birds were highly divergent in their DNA, almost as different as the distinctive Bicol Ground-Warbler in southern Luzon.
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Source: Kansas University.
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