Sedge warblers are migratory, crossing the Sahara to get from their European and Asian breeding grounds to spend winter in Africa. The sedge warbler is mostly insectivorous.
The male's song is composed of random chattering phrases and can include mimicry of other species. The song is varied, rushed and chattering, with sweeter phrases and some mimicry. It is composed of phrases in random order, so that it is never the same. Male sedge warblers which have the widest repertoire mate with the largest number of females.