The Sedge Warbler (Acrocephalus schoenobaenus) is a lively reed-dwelling warbler best known for its broad, bright white eyebrow stripe and its improvised, constantly varying song, often delivered in a short display flight up out of the reeds. It is a small warbler, about 12–14 cm long with a wingspan of 17–21 cm and a weight of only 10–14 g. Unlike its close relative the Reed Warbler, its upperside is clearly streaked with dark markings on the back, while the underside is pale and unstreaked, often with a warm yellowish-beige tone on the flanks. The white eyebrow stripe is the most reliable field mark, giving the bird a distinctive expression, and the crown is dark with a warm rust-brown rump — both marks show best when the bird perches briefly in the open, which it often does during its display flight.
Its song is varied and improvisational, an irregular stream of harsh and whistling phrases, trills and mimicry of other species, often rendered as "tjerr-tjerr-lili-tjerr" with constantly shifting tempo and pitch, and the bird frequently sings while rising from the vegetation on vibrating wings before dropping back down. Sedge Warblers breed across almost the whole of Sweden, even reaching the willow and birch belts of the fells, with a large national population of some 100,000–200,000 pairs and a status of Least Concern; less strictly tied to tall reed than the Reed Warbler, it also occurs in lower shore vegetation. It builds a bowl-shaped nest low in dense vegetation, often shoreline grass, sedge or bushes near water, laying 5–6 eggs, and both parents feed the young, which leave the nest before they can fly and stay hidden in cover until they can. The diet is insects, spiders and other invertebrates gleaned from shore vegetation, and before its long migration to wintering grounds in sub-Saharan Africa, the bird builds up fat reserves as fuel for the journey.
Read about this species in Swedish →