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

[3] This is a bird of open but shady mature woodlands, such as beech and sessile oak, with some sparse ground cover for nesting.

It can be distinguished from similar species, like the chiffchaff P. collybita and the willow warbler, P. trochilus by its yellow supercilium, throat and upper breast, pale tertial edges, longer primary projection, and by its shorter but broader tail.

[7][8] It has two song types, often (but not always) given alternately; a high-pitched fluid metallic trill of increasing tempo pit-pit-pitpitpitpt-t-t-tttⓘ lasting 2–3 seconds, and a series of 3 to 5 descending piping notes of lower pitch piüü-piüü-piüü.

The contact call is a soft piping note, similar to the second song type, but shorter and given singly, piü.