Each winter flocks return to Slim bridge, the largest congregation of the species in Britain.

Young that have left their nest remain nearby until well after their moult, before departing for winter flocks, followed later by the adults.

Little passage is recorded in the spring, although there is fairly steady decline in the winter flocks after February.

In winter huge flocks of greylag geese and greater white-fronted geese shelter here.

Where additional food is available, winter flocks are larger and contain a high proportion of immature birds.

This was odd as it indicated that the winter flock had already scattered as separate pairs at this very early date.

The winter flocks of finches were lost, the yellowhammers disappeared, the skylarks nearly so.

Each fall and winter, vast flocks gather in Rome.

This bird is often solitary, but joins with other birds in winter flocks.

During the day, these large winter flocks break up into smaller flocks.