This warbler is strongly migratory; the entire population winters in southeast Asia.

Its single wing bar distinguishes it from most similar species except the greenish warbler, Phylloscopus trochiloides.

It is larger than that species and has a heavier, dagger-like bill, with a dark tip to the lower mandible.

This species occurs as an autumn vagrant in western Europe and is annual on Great Britain.

[3] The genus name Phylloscopus is from Ancient Greek phullon, "leaf", and skopos, "seeker" (from skopeo, "to watch").