The all-black male with his bright yellow bill is unmistakable and the female is distinctively dark brown all over with only obscure streaking on the breast.
Breeds and winters in woods, farmland, gardens, wasteground and hedges.
Blackbirds are one of many species which indulge in 'mate-guarding' whereby, when the female is in her most fertile period, the male never leaves her side. It would be sentimentally nice to think that he is protecting her but actually he is keeping watch on her to make sure she doesn't sneak off and copulate with a rival male. Once he knows she is no longer fertile he becomes much less attentive.
Resident or migratory depending on distribution. Birds from Scandinavia will winter in Britain while some British birds will move southwards.