Systematic notes on Asian birds. 41. Territorial songs and species-level taxonomy of nightjars of the Caprimulgus macrurus complex, with the description of a

The Large-tailed Nightjar Caprimulgus macrurus Horsfield, 1821, complex, as currently recognized, comprises 12 taxa which are grouped into four species based on their territorial songs. However, species limits are based on very small samples of a limited number of taxa in the complex. To further document species limits in the complex, we analysed 109 sound recordings representing all recognized taxa. Principal components analysis suggests the existence of six vocally distinct groups within the complex. Discriminant function analysis assigned 98-100% of individuals correctly to their group. Each of these groups differs diagnosably from all other groups by up to eight vocal characters, and each group is recognizable by ear. We propose to treat these six groups as species based on multiple differences in territorial songs, the lack of intermediate vocal types, the concordance of the geographic distribution of vocal types and morphology-based taxonomic boundaries and the sympatry of two groups in northeastern peninsular India without signs of intergradation. Three groups correspond to the currently recognized species C. atripennis Jerdon, 1845, C. celebensis Ogilvie-Grant, 1894, and C. manillensis Walden, 1875. ’C. macrurus’ comprises three vocally distinct species: (i) C. macrurus (s.s.), with a territorial song that is remarkably constant throughout its extensive range, (ii) C. andamanicus Hume, 1873, a population endemic to the Andaman Islands, and (iii) a previously unrecognized species from the east Indonesian islands of Flores and Sumba, which we describe in this paper. Known specimens of this new species were previously assigned to C. macrurus schlegelii A.B. Meyer, 1874, but the species differs from all other taxa in the complex by its vocalizations. Preliminary playback experiments support the recognition of these populations as a species. Finally, our acoustic data corroborate the allocation of the taxon aequabilis Ripley, 1945 to C. atripennis, of jungei Neumann, 1939 to C. celebensis, and of johnsoni Deignan, 1955 and salvadorii Sharpe, 1875 to C. macrurus.