The male common blackbird defends its breeding territory, chasing away other males or utilising a "bow and run" threat display.
This consists of a short run, the head first being raised and then bowed with the tail dipped simultaneously.
If a fight between male blackbirds does occur, it is usually short and the intruder is soon chased away.
The female blackbird is also aggressive in the spring when it competes with other females for a good nesting territory, and although fights are less frequent, they tend to be more violent.

The bill's appearance is important in the interactions of the common blackbird.
The territory-holding male responds more aggressively towards models with orange bills than to those with yellow bills, and reacts least to the brown bill colour typical of the first-year male.
The female is, however, relatively indifferent to bill colour, but responds instead to shinier bills.

As long as winter food is available, both the male and female will remain in the territory throughout the year, although occupying different areas.
Migrants are more gregarious, travelling in small flocks and feeding in loose groups in the wintering grounds.
The flight of migrating birds comprises bursts of rapid wing beats interspersed with level or diving movement, and differs from both the normal fast agile flight of this species and the more dipping action of larger thrushes.
The male common blackbird defends its breeding territory, chasing away other males or utilising a "bow and run" threat display. This consists of a short run, the head first being raised and then bowed with the tail dipped simultaneously. If a fight between male blackbirds does occur, it is usually short and the intruder is soon chased away. The female blackbird is also aggressive in the spring when it competes with other females for a good nesting territory, and although fights are less frequent, they tend to be more violent.
The bill's appearance is important in the interactions of the common blackbird. The territory-holding male responds more aggressively towards models with orange bills than to those with yellow bills, and reacts least to the brown bill colour typical of the first-year male. The female is, however, relatively indifferent to bill colour, but responds instead to shinier bills.
As long as winter food is available, both the male and female will remain in the territory throughout the year, although occupying different areas. Migrants are more gregarious, travelling in small flocks and feeding in loose groups in the wintering grounds. The flight of migrating birds comprises bursts of rapid wing beats interspersed with level or diving movement, and differs from both the normal fast agile flight of this species and the more dipping action of larger thrushes.
Common blackbird