Also known as Pallas's warbler it is one of the smallest warblers; at 9?10 cm long and 4?7 g weight it is slightly smaller than a yellow-browed warbler and barely any larger than a goldcrest. Overall, it has greenish upperparts and white underparts, but is very striking, with prominent pale yellow wingbars on the tips of the greater and median coverts, bold yellow supercilia and central crown stripe, and a lemon-yellow rump. It is not shy, but its unobtrusive arboreal lifestyle makes it difficult to observe. It is constantly in motion, and often hovers briefly like a Goldcrest.


Habitat and Distribution

It breeds in coniferous taiga and mountain forests. It breeds in southern Siberia (from Novosibirsk Oblast east to Magadan Oblast), northern Mongolia, and northeastern China. It is strongly migratory and winters mainly in subtropical southern China and northeastern Indochina, but also in small numbers in western Europe.


Feeding

Like most warblers, is insectivorous.


Breeding

The nest is built in a tree, usually next to the trunk at 0.5?10 m above ground; four to six eggs are laid, hatching after 12?13 days, with the chicks fledging when 12?14 days old.


Calls and Songs

Its song is a medley of whistles, with some phrases reminiscent of a canary ; the call is a short chweey.