157986 Dartford Warbler - Sylvia undata. (L 12-13cm), often seen perched on a Gorse spray with its tail cocked up, is emblematic of heathland conservation. Adults have blue-grey upperparts, reddish underparts with a white belly, a beady red eye and reddish eyering, and pinkish yellow legs; males are brighter than females. The species is often first detected by sound: it utters a tchrr-tche alarm call and has a rapid, scratchy warbling song. Dartford Warblers are restricted to Gorse-covered heathland areas in southern England and are mainly resident.