A songbird species previously thought to occur across two Indonesian islands has turned out to be two distinct species, according to a recent study. For more than 120 years, many scientists believed that Indonesia’s Babar Islands in eastern Banda Sea, and Tanimbar Islands, roughly 135 kilometers (84 miles) east of the Babar Islands, were both home to the cinnamon-tailed fantail (Rhipidura fuscorufa). But a team of researchers led by James A.

Eaton of Birdtour Asia Limited and Alex J. Berryman of BirdLife International has confirmed that the songbird on Babar Islands is a distinct species, which they’ve named the cheerful fantail (Rhipidura laguceria). To confirm these findings, the researchers analyzed 19 museum specimens of birds labeled cinnamon-tailed fantail, historically collected from both Tanimbar and Babar islands.

They also recorded songs of the birds on both islands, then played the recorded calls back to the wild birds 132 separate times over several years. The researchers found that physical differences between the populations on the two islands are subtle: The cheerful fantail possess slightly darker upperparts and less extensive cinnamon plumage below than the cinnamon-tailed fantail. However, their songs vary considerably.

The researchers said in the study that songs of the birds on Babar typically consist of “single whistles that rise in pitch towards the end.” By contrast, the Tanimbar birds combine very short and longer whistles, which gives their songs a “much more rhythmic cadence,” with pitch that typically goes up and down. The song recording experiments also revealed that birds…This article was originally published on Mongabay