Sanderling of the UK and Ireland
The Sanderling (calidris alba) is a small wading bird from Siberia that winters along the coasts of Britain and Ireland. Wintering Sanderlings from Greenland fly over when migrating to and from their wintering grounds in West Africa. It is also known as the Ruddy Plover and Sand Runner (Ireland).
The Sanderling is about the size of a Dunlin and is much whiter than other waders in winter. Adults measure 20 to 21 cm (or 7.9 to 8.3 inches) and weigh between 50 and 60 grams (or 1.8 and 2.1 pounds).
Males and females are alike. The upperparts are pale grey and the underparts are white in winter with a dark shoulder patch. In the summer, the plumage on the upperparts, head and breast are mottled with black, white, grey and chestnut colours. The bill is short and stout. A white wing-bar can be seen during flight. The legs are black. Immature birds are mottled with black on the upperparts with some buff on the breast.
It belongs to the Scholopacidae (or Sandpiper) family of birds that includes its cousin, the Dunlin. Adults start breeding when they are 2 years old. The average lifespan of these birds is 7 years.
Sanderlings, who are sociable and active birds, inhabit the open coast and includes sandy beaches, mudflats, rocky shores, coastal pools, saltmarshes and estuaries. Very few are found inland on lakes and reservoirs. They often form large flock with other waders, such as the Ringed Plover, on sandy beaches or mud-flats.
Most members of the Sandpiper family of birds have a fourth toe (hind toe) but the Sanderling differs as it has only 3 toes (or no hind toe). The toes are also separated. This adaptation allows it to run and walk quickly on firm surfaces.
The diet includes marine worms (ragworm), molluscs, insects and small crustaceans (sandhoppers). Seeds, nuts and some plant material (roots, stems) are also eaten. They are usually seen foraging for food and roosting together in small flocks, often with other waders such as Dunlins.
Sanderlings are hyperactive birds who use a "bicycling" action as they run across the sand and stop for a few seconds to probe the ground or pick up bits of food. Foraging also takes place along the edge of waves of a beech, quickly snaching food as the waves retreat and running away as it moves in.
Wintering Sanderlings from Siberia arrive in Britain and Ireland between August and September. Sanderlings from north-east Greenland use Britian and Ireland as a stopover point when migrating to and from their wintering grounds in West Africa. It has been found that some birds stay for the winter whereas before it was thought that they were birds of passage. Wintering birds can be seen on estuaries and along the coast. They return to their breeding grounds between May and June. Their flight is fast and low, often in well coordinated groups.
The most important wintering sites in Enlgand include the Ribble (Lancashire), Morecambe Bay (Kent), the Wash (Norfolk), Dee Estuary(Wales) and Teeside ( High Beam). They may be seen Dublin Bay and Akeragh Lough in County Kerry in Ireland.
The Sanderling Project is currently studying these birds so that certain aspects of their lives (eg migration) may be answered ( International Wader Group).
Sanderlings breed in the Arctic regions of Siberia and Greenland. They do not breed Britain and Ireland.
The global population is not considered Vulnerable by conservationists (such as Birdlife International) due to the wide range of these birds (Europe, Asia, Africa, North America etc). The European population is considered Secure.
The Sanderling is classified as of Least Concern by IUCN.
The UK population increased by 34% between 2000 and 2009 (RSPB) where they are an amber listed species of bird. The WeBS reported an increase in the population of Sanderlings in the UK between 2012 and 2013 ( WeBS - page 11). The Sanderling is green listed in Ireland.
The main threats are human disturbance (dog walking, motor vehicles), changes in nutrient levels of water (eg changes in sewerage treatment), commercial overfishing of shellfish (mussels and periwinkles), estuarine development, land reclamation ( Durham Bio-diversity), pollution and avian flu.
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