Our Returning Wild Geese And Swans
Every year during the first week of September, just like clockwork, a distant honking in the skies signals the return of the migratory geese and swans. Throughout the following two months we down tools at dusk to watch the huge skeins flying high and low over the gardens. Early October is peak viewing time, with flock after flock appearing in perfect 'V' formation against the pink sunset, Mars twinkling away to the north.
Most numerous are the dark-bellied Brent geese, heading back from Northern Russia to overwinter in southern and eastern England. They nest on the boggy Arctic tundra, where the severe climate allows them only two months in which to raise a family. By September the geese have left their breeding grounds, migrating in family groups and travelling mostly at night. At dawn they search for marshland, coastal grassland or farmland on which to rest and feed for the day, before pushing on again when evening falls. Where the grazing is good they might linger for a week or longer but by early October most have arrived in England, settling around estuaries and in the fields of sugar beet they find so delectable.
Pink-footed geese are medium-sized,'smaller than a mute swan but bigger than a mallard'. They are pinkish-grey in colour with a dark head and neck and, unsurprisingly, pink feet and legs. They breed in Iceland and Greenland and every autumn tens of thousands migrate to the Wash, whose inaccessible tidal mud-banks offer a safe haven, packed with worms and molluscs for a feeding frenzy. Pink-foots are known for their loud honking call whilst in flight and for travelling in particularly large skeins.
Some of the geese we see are not true migrants at all. Canada geese were introduced to St James's Park in London in 1665 and have been naturalised in England for centuries, but instinct still leads them to fly north in what is known as a 'moult migration'. They gather at remote sites selected for abundant food supplies and protection from predators, where they can safely shed and regrow their flight feathers - a process that leaves them grounded and vulnerable.
Two species of wild swan also overwinter in Britain, the whooper and the Bewick. These tend to be the last of our arrivals, sometimes not appearing in the skies until November. The whooper is the same size as our familiar mute swan and the name derives from its mournful cry on the
return flight from eastern Iceland. The smaller Bewick or tundra swan has an even longer journey, travelling more than 2,000 miles from western Siberia. Bewicks migrate in stages, gathering first on the southern shores of the Baltic, then in the Low Countries, finally arriving in Britain for only a brief sojourn before heading back to Russia in February. Unlike their mute swan cousins, wild swans are highly gregarious and demonstrative, using vocal signals and displays to keep the family and the flock together.
WHY DO THEY FLY IN SKEINS?
Why geese, swans and other large-winged birds fly in V formation remained a mystery until researchers from the Royal Veterinary College fitted a flock of ibis with data loggers. These monitors revealed that the skein
synchronises wing-beats, with each bird making the most of upward-moving air generated by the one in front. Lead researcher Dr Steven Portugal explains in the journal Nature: 'They're seemingly very aware of where the other birds are in the flock and they put themselves in the best possible position for ease of flight.'
Copyright © Karen Meadows 2018