Asian Brown Flycatcher (Muscicapa dauurica)

In past, sometimes considered conspecific with M. randi and M. segregata. Fairly distinctive race williamsoni commonly treated as a separate species, although seemingly mainly on basis that breeding range approaches that of siamensis, but no overlap yet demonstrated and a few individuals in shared non-breeding range have been considered intergrades; further study required (especially of voice: to date no recordings of williamsoni available) including of race umbrosa, which may represent a third species or be treated with williamsoni#R. Race sodhii recently described as a full species#R, but genetic and morphometric evidence in description place it close to (or within range of variation in) present species as here constituted, while stated plumage differences amount to three minor ones (but race siamensis, genetically closest, was not compared; score at best 3) and detectable song differences, involving fewer low-pitched notes, are based on a single individual and require substantiation and fuller analysis (claim that lowest frequency in sample was 5.75 kHz contradicted by analysis here, which found 2.2 kHz; and claim that maximum frequency higher also contradicted by other sampling), including comparison with geographically closest race umbrosa, whose song is apparently unknown#R. Species has occasionally been listed as M. latirostris, as Pallas’s name claimed to be infrasubspecific#R, but ICZN Code supports its validity#R. Six subspecies recognized.