Acrocephalus schoenobaenus
A mouse-like reedbed warbler that can double its body weight before migrating.
Size: 11.5-13 cm | Habitat: Pond, Lake & River Birds | Season: Summer visitor
Streaked brown above with a bold creamy eyebrow stripe, the sedge warbler creeps mouse-like through reeds and waterside scrub rather than perching in the open like its relative the reed warbler. Its fast, scratchy, improvised song is a familiar sound of reedbeds and ditches in early summer.
Broad creamy eyebrow stripe · streaked brown back · plain unstreaked underparts · cinnamon-tinged rump
Sedge warblers favour reedbeds, ditches, and waterside scrub, creeping through low cover rather than perching openly. Males occasionally deliver their scratchy song in a brief fluttering song-flight.
Before migrating south, a sedge warbler can almost double its body weight in fat, then fly nonstop for up to 60 hours over open sea and desert to reach its wintering grounds south of the Sahara.
The Sedge Warbler (Acrocephalus schoenobaenus) is a streaked brown warbler with a bold creamy stripe over the eye, told apart from the plainer reed warbler by that eyebrow and its habit of creeping mouse-like through low waterside cover.
Like the whitethroat, sedge warbler numbers crashed dramatically in the late 1960s when severe drought struck the Sahel region of Africa, where the species winters, and numbers still fluctuate from year to year depending on rainfall there. Before its return migration, a sedge warbler can nearly double its body weight in fat reserves, enabling a nonstop flight of up to 60 hours over open sea and desert.
This reliance on a single, drought-prone African wintering region explains the sedge warbler's Amber listing, and makes it another clear example, alongside the whitethroat, of how a British breeding bird's fate can be decided far outside the UK.
🟠 Conservation status: Amber (UK Birds of Conservation Concern 5)
Amber-listed, reflecting a history of sharp population swings driven by Sahel drought in its African wintering grounds — a pattern shared with several other UK warblers that winter in the same region.