Range & Status
Europe and west Asia; in Britain and Ireland colonised southern England, with first breeding record in 1972; now (1990s) fluctuates between 200 and 350 pairs.
Cornwall: first recorded in 1973, now a very localised resident, with some dispersal in autumn and winter. Numbers fluctuate, with peak highs in 1984 (11 sites, some 15 singing birds) and 1993 (12 sites, some 30 singing birds). The main sites are Marazion (nine in song, with a further 27 trapped, in 1985), Gunwalloe (six in song 1991) and Par (five in song 1993). Isles of Scilly: absent.
Habitat & Ecology
Prime habitat is reed-beds with ditches and scrubby cover, i.e. Willows Salix spp. and ditches bordered by Bramble Rubus fruticosus agg. Males are polygamous; therefore the potential for population explosions is good.
Severe cold spells in winter has created population crashes in south-east England.
Main sites are SSSI. Listed (long list) as a globally threatened/declining species (BSGR, 1995).