Redwing bird is a small thrush, boldly marked with a long whitish supercilium and whitish submoustachial stripe framing the brown ear coverts. The underparts of redwing bird are white with a buffish wash across the breast, a dark malar stripe and bold dark streaks and mottling on the breast and flanks. The flanks are brick-red, as are the underwing coverts. The upperparts are uniform olive-brown.
Redwing bird is a common winter visitor to Britain, with odd pairs staying to breed in Scotland. Commonly found in northern Europe, breeding mainly in coniferous forests but also in mixed forest, scrub and birch. Often favours river valleys and damp areas, and will nest in parks and gardens. In winter in Britain it is found in farmland with berry-bearing hedgerows, open woodland and occasionally in parks and gardens.
The commonly heard call in Britain is uttered in flight, a thin, slightly buzzing and descending "tszeeep", often heard from migrant birds flying over at night. Redwing bird also has a soft "pok" or "chup" note given by perched birds, a nasal "gak", and on the breeding grounds gives a dry scolding rattle, a hard stony "trrrr trrr ktrrrr" or "trrac trrac". Migrant flocks at rest also give a collective twittering and chuckling. The song varies much between individuals, and is a loud clear sequence of three or four repeated notes lasting 1 -2 seconds, almost always followed by a strangled, hard-to-transcribe, warbling and squeaky twittering phrase that lasts two or three times as long as the clear note phrase. Variants are a rising "tlui-tlui-tlui", a descending "vee'du-vee'du-vee'du", a level-toned "tui-tui-tui-tui", a steeply ascending "kt'rt'tr'tr'tr'tr'tr" and a cheery "ki-chirri-chirri-chirri-chirri", delivered on a level tone, all followed by the twittering "ksch't't'rr'ttschrr'tr't'tii".