Pallas's Leaf Warbler

Pallas's leaf warbler (Phylloscopus proregulus) or Pallas's warbler is a bird that breeds in mountain forests from southern Siberia east to northern Mongolia and northeast China. It is named after the German zoologist Peter Simon Pallas, who first formally described it. This leaf warbler is strongly migratory, wintering mainly in south China and adjacent areas of southeast Asia, although in recent decades increasing numbers have been found in Europe in autumn.

Pallas's leaf warbler is one of the smallest Palearctic warblers, with a relatively large head and short tail. It has greenish upperparts and white underparts, a lemon-yellow rump, and yellow double wingbars, supercilia and central crown stripe. It is similar in appearance to several other Asian warblers, including some that were formerly considered to be subspecies of it, although its distinctive vocalisations aid identification.