I LIVE beside the sea, where the arrival of the seasons is announced on the avian public address system.
Spring is ushered in, shortly after St Patrick’s Day, by the ‘kik-kik-kik’ of sandwich terns who have worked their way up the coast from Africa. In October, the gentle purring of brent geese, just arrived from Arctic Canada, will mean that winter has arrived.
This month, the plaintive whistling of common sandpipers can be heard, a sure sign that autumn isn’t far away. The Séamus Ennis of the wader world doesn’t stay on the coast for long; he’s soon on his way to Africa. Heading south with him, will be swallows and warblers, strange bed-fellows. Only one other Irish wader migrates in such company; the smaller version of the curlew, the whimbrel, also travels to the deep south for the winter.
But an unusual migration pattern isn’t the common sandpiper’s only idiosyncrasy. This bird may look like your typical wader, smaller than a starling, brown on top and pale on the belly, but appearances are deceptive. The musical prodigy has a mind of its own and does things differently from other waders.
Some Irish waders stay here to breed, as do oystercatchers and curlews. Others, such as godwits and redshanks, head north to Iceland or Scandinavia. The common sandpiper, however, lives in sub-Saharan Africa and comes here to breed. It arrives at the end of April, setting up shop on the same territory every year. The eggs are hatched by the end of June. The family stays together for about a month, until the youngsters become independent. Then it’s back to Africa.
Most migrant birds moult at the end of the breeding season. It makes sense to grow a pristine set of flight feathers before setting out on a long arduous journey. Common sandpipers, however, are so anxious to get back to their beloved Africa that they travel on their old feathers and don’t grow new ones until they get there. Birds which have not bred, or whose nests have failed, are the first to leave; some are on their way by mid June. Those on the move just now are probably Irish or Scottish breeders. Scandinavian birds nest later and will pass through Ireland next month.
Most waders migrate along coasts, but sandpipers seem to move on a broad front, flying over deserts and crossing mountain ranges. The British Trust for Ornithology’s Migration Atlas mentions that a common sandpiper, which had been ringed as a chick in Yorkshire, was found a few months later in the radiator of a plane at Moscow Airport. The plane had flown from Accra via Belgrade, with almost all of the journey over land.
Wetland birds generally spend the winter months in flocks, feeding and roosting together, but here, once again, common sandpipers do there own thing. An unsociable lot, they live solitary lives along African rivers. They even stake out winter territories, stretches of river about 200kms long, much the same size as their breeding ranges in Europe. During a study of a river valley in Senegal, 65 common sandpipers were ringed. Of these, 14% were captured again in subsequent years, a much higher re-trap rate than for the other waders ringed in the study. This can only mean that the sandpipers returned to the same territories every year. They also engage in sexual activity in Africa, although there are no records of nesting attempts.
But the common sandpiper is no temperamental prima donna. This is an adaptable species, which breeds throughout Europe and Asia from the south of Spain to the coast of Siberia wherever there are suitable rivers or lakes.
It will tolerate huge variations in climate and exploit a range of habitat types. It particularly likes fresh, clear lakes and clean, rocky upper streams. Mudflats and estuarine salt marshes, the favourite haunts of most waders, are avoided.
Nests are always located near water. The male helps with the nest building and does his share of the incubating. Birds of either sex will perform ‘chick imitation’ displays, fluttering along the ground to lead intruders away from the eggs. Once the chicks have hatched, their parents will put on ‘distraction’ displays, in which a bird pretends that its wing is injured and that it has difficulty flying. Although some sandpipers remain paired from one year to the next, most birds go their separate ways in the autumn and team up with a new partner the following year.
But the common sandpiper’s most endearing features is its clear piping song. We tend to associate singing with garden birds, but waders also sing and some are accomplished performers. The song of the curlew, for example, is one of Ireland’s most characteristic sounds. Just why waders sing is a bit of a mystery. Birds which live in forests have little choice but to sing; they can’t see each other and have to resort to sound to communicate. Waders, however, live in open spaces where they are more visible. Ducks quack, geese honk and swans whoop but their vocabulary is basic. Only waders, among the wetland birds, have developed complex songs.
In the bird world, generally, the males do the singing. Among waders, however, both sexes sing.
Just why sandpipers sing when on migration, attracting unnecessary attention to themselves, is another of their secrets.
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