Yellow-browed Warbler

The yellow-browed warbler is one of the smaller Old World warblers, 9.5–11 centimetres long and weighing 4–9 grams, distinctly smaller than a chiffchaff. Like many leaf warblers it is greenish above and white below, with prominent double wing bars formed by yellowish-white tips to the coverts, yellow-margined tertials and a long yellow supercilium. Some individuals show a faint paler green central crown stripe. Two former subspecies are now treated as a separate species, Hume's leaf warbler, which differs slightly but consistently. (Wikipedia, general species account)

This is an abundant insect-eating bird of lowland and montane forests and woodlands, and in winter it may also use more open woods. Its breeding range extends from just west of the Ural Mountains east to eastern Siberia, Mongolia and Northeast China, and it is strongly migratory, wintering mainly in tropical South and Southeast Asia and in small numbers in western Europe. The nest is built in dense vegetation, often at the base of a tree or old stump, and two to four eggs hatch after 11–14 days. (Wikipedia, general species account)