A bush-warbler of the genus Bradypterus, known from the mountains of Taiwan
since 1917, has never been formally named as a distinct taxon. Songs of th
e Taiwan population differ strikingly from those of its Asian congeners in
being much clearer, sweeter, more piercing, and in having a very different
structure of elements. Several subtle but consistent morphological differen
ces exist between specimens from Taiwan and all named taxa, principally in
bill size and shape, plumage color and reduced variability, pattern of unde
rtail coverts, and wing formula. Therefore, the Taiwan population is best t
reated as a new species.