Martens's Warbler Phylloscopus omeiensis

A bright and attractive small warbler with many virtually identical relatives. Breeds in foothill and montane forests, where it favors areas with a dense understory. Descends into lower elevations in the winter, when it often moves around with mixed flocks. Bright green above and yellow below, with a gray-and-black-striped crown and a bright yellow eyering; note intermediately strong crown patterning and distinct yellow eyering, often weak but not broken above the eye. Song is a series of lively whistles and chirps uttered in discrete bursts.