Discovery of the Large Blue Flycatcher Cyornis [banyumas] magnirostris breeding in northern Kachin State (Burma/Myanmar) and taxonomic implications for the Cyornis-group

The little-known taxon Cyornis [banyumas] magnirostris has long been treated as a race of the widespread Hill Blue Flycatcher C. banyumas, with which it was thought to be allopatric during the breeding season. On the basis of morphology, magnirostris has lately been considered a full species, endemic as a breeder to northeastern India. Our recent field work during migration and the breeding season (September 2005 and June–July 2006) has, however, resulted in the first records of magnirostris from northern Burma/Myanmar, establishing that its breeding range broadly overlaps the range of C. banyumas whitei. We demonstrate how historical factors, sources of error, including fraud, errors of omission and commission, and inferences based on lack of data have all negatively affected assessment of species limits and conservation status in this speciose group of flycatchers. We also provide evidence that the taxon C. [banyumas] lemprieri is highly distinct and should be treated as a full species.