Research into their lives reveals that outside the breeding season both males and females sing to declare and defend their own individual territories. Songs are identical. Behaviour changes around Christmas-time. Robins begin exploring other robins' territories seeking a mate. By mid-January the majority will be paired and the females stop singing.
Male robins continue singing, declaring what has become a joint future breeding territory.
On occasions singing lasts into the night especially where street lights are prominent. Detailed research shows that a few robins hold more than one territory simultaneously for up to six weeks. These are usually adult males moving up to a third of a mile between breeding and winter territories. British robins are largely resident. However some, mostly females, cross the Channel to spend the winter as far south as southern Spain and Portugal.