Sakhalin Leaf Warbler

The Sakhalin leaf warbler is a small Phylloscopus with a long white supercilium, broad dark-brown eye-stripe, dark crown and upperparts, mottled ear coverts and greenish-brown cheeks. The bill is dark with pink at the base of the lower mandible, and the legs are pale pinkish-brown. It closely resembles the pale-legged leaf warbler; slightly greener upperparts may help, but voice is generally a more useful distinction (Wikipedia, general species account).

It breeds in temperate forest on Sakhalin, the Kuril Islands and Japan, nesting in shrubs, and migrates south through East Asia to winter around the Amami and Okinawa islands and in Indochina. Its lower-pitched vocalizations usually separate it from the pale-legged leaf warbler, although the pitch ranges overlap. Korean records are best assessed with calls as well as plumage because visual separation can be difficult during migration (Wikipedia, general species account).