Fair-feather friends

Come autumn, millions of migrant birds flock to Britain to overwinter here. Stephen Moss charts their gruelling journeys from the Arctic, Scandinavia and Siberia and considers why they are prepared to fly so far

EVERY spring, people across the country eagerly await the arrival of birds such as the swallow, swift and cuckoo, which return to Britain to breed and raise a family. We may not be so aware of another group of migrants: those that come each autumn from the north and east to spend the winter months on the British Isles. These birds might not travel quite so far across the globe, yet their arrival is, if anything, even more of a spectacle, as they gather in vast flocks to feed in our fields, marshes, estuaries and coastlines.

They include many large birds, such as ducks, geese, swans and waders. Yet, among their number is a host of songbirds, such as starlings, thrushes and even some warblers —birds we traditionally think of as summer visitors to our shores. They all come here for the same reason: to find enough food to enable them to survive the winter, before they return to their spring and summer homes to breed.

As we brave the chilly air for a walk in the middle of winter, we might not think that Britain’s climate is especially mild. However, compared with the locations migrant birds come from—the Arctic, Scandinavia and Siberia—our winters are positively tropical. This is largely thanks to the warming presence of the Atlantic Ocean and its ocean currents, which make our winter climate much milder than equivalent latitudes around the world. Although the days are short, particularly around the winter solstice, when there may be less than eight hours of daylight, this still offers a lot more time to feed than the 24-hour darkness beyond the Arctic Circle.