Species delimitation in the White-faced Cuckoo-dove (Turacoena manadensis) based on bioacoustic data

The White-faced Cuckoo-dove (Turacoena manadensis) is a poorly-known Wallacean endemic with a limited distribution on Sulawesi and its satellites, including the Togian, Banggai and Sula archipelagoes. In 1900, populations from the Sula archipelago were awarded subspecies status T. manadensis sulaensis based on smaller size and minor differences in plumage; however, this distinction has not been corroborated subsequently, and T. manadensis is considered by most modern sources to be monotypic across its range.

We conducted vocal analysis of the cuckoo-doves' main song using recordings collected from across the taxon's natural range. Descriptive information on the songs was obtained from the recordings using bioacoustic analysis software, after which several statistical methods were used to investigate differences in vocalizations among populations.

We report deep bioacoustic divergences in vocal trait pattern from across the cuckoo-doves' range, with birds from Peleng and Taliabu in the east having a different vocal trait pattern from birds from Sulawesi, Buton, and Togian in the west. These patterns agree with changes in landmass that accompanied the sea level fluctuations caused by Pleistocene glacial cycles, and indicate that eastern and western cuckoo-dove populations are at the level of different biological species.

We propose that the eastern taxon be elevated to species level as T. sulaensis. Given the rampant degree of habitat destruction in its limited range, this taxonomic change will have important implications on the conservation status of T. sulaensis.