L 13-14 cm. Breeds in N Europe among willows and soggy upland birch forest, in rest of Europe in swampland by fens and rivers overgrown with bushes, reeds, alder etc. Summer visitor, winters mainly from NE Africa to W India. Passage migrant in Britain (Mar-May, Aug-Oct). Food insects. Nests in tussock or low in dense willow bush.
IDENTIFICATION: A rather small and slim bird with long thin legs, in all plumages told by obvious whitish supercilium and rusty-red patch on sides of tail-base (often seen in flight, or when perched bird flicks tail up). - male: Bright blue bib, bordered below by a narrow black and white band and a broader rusty-red one. Inlaid in centre of the blue, birds in chiefly N Europe (ssp. svecica) have a rusty throat patch, those in rest of Europe, E Turkey and Caucasus (incl. cyanecula, magna) a small white patch or none at all. In autumn, some of the bright throat colours are replaced by yellowish-white areas. - female: Variable throat markings; usually just an arc of black spots on creamy-white ground, older birds occasionally with some blue, plus black and rusty border across breast (those with most blue can look quite a-like). - Juvenile: Finely spotted like juvenile Robin, but note tail markings.
VOICE: Commonest call a dry, throaty clicking ‘track’ (like flag halyard flapping in the wind). When agitated, also a wheatear-like whistled ‘hiit’ (and at times a Redstart imitation, ‘huit’). In autumn a hoarse, cracked ‘bzrü’ may also be heard. Song powerful and clear, often starts with a long-repeated, loud, metallic ‘zrü’, or a polysyllabic ‘zri-zri-zrütt’ or the like, which slowly speeds up and suddenly turns into a cascade of melodious or hard and squeaky notes, often mixed with good imitations of other species (even reindeer bells may be mimicked!).