http://wildbirdseeds.co.uk/lincs/index.php/whats-that-bird-mainmenu-7/56-redwing#sigProId8f6b912d94
Identification
The Redwing most closely resembles the Song Thrush but is best identified by the obvious buff stripes over its eye and through the moustache. These features are often more obvious than the red flanks and red underwing which give the species its name.
Habitat
Breeds in Norther Europe in woodland and scrub. Winters in hedges, fields, and gardens.
Behaviour
Redwings often sing in their winter quarters, especially towards the end of the winter. This singing is usually performed by birds in flocks which obviously aren't defending a territory or indeed planning to, unless the territory is confined to their bit of space within the flock.
Migration
A migrant or partial migrant depending on range. Northernmost populations winter in western Europe from Scotland southwards.
For more details click here