The status, subspecies and migration routes of Dunlin Calidris alpina breeding on Svalbard

Probably fewer than 300 pairs of Dunlins Calidris alpina breed in the archipelago of Svalbard, mainly in Nordenskiöld Land on the island of Spitsbergen. Genetic studies have shown that they are most similar to C. a. arctica breeding in NE Greenland, but also show some similarity to populations of C. a. schinzii breeding around the Baltic Sea. Until now, migration routes and subspecies status of Dunlins on Svalbard have been unclear, as there were no records to show whether they shared similar migration routes or wintering areas to C. a. arctica or C. a. schinzii. We present 73 sightings of 52 individual Dunlins colour-marked on Svalbard and two recaptures of birds with only metal rings to document, for the first time, the migration routes and wintering areas of the population. We also describe their bill lengths and breeding plumage and compare these to published data on other Dunlin populations. In July–October the sightings of individually marked birds suggest that they have two initial migration routes through northern Europe, through (1) the Baltic and (2) southwestern and southern Norway. Further south the route is then along the Wadden Sea coasts to western France, but four birds were also observed in southern England. In November–January, marked birds were recorded in southern France, on the Iberian Peninsula, in Tunisia and on the Banc d’Arguin in Mauritania. In April–May, they were recorded in northern Spain, southern and western France, the Netherlands, Denmark and Latvia. Most records were from the second half of May, but two records were from April, in southern France and western Denmark. Four birds marked as juveniles migrated north in their second year. One was in western France on 5 June, one was sighted on Svalbard and two were sighted on southward migration in Denmark and eastern England. No Svalbard Dunlins were seen on the main wintering areas of C. a. alpina in western Europe and the plumage and bill lengths were more similar to those of C. a. arctica and C. a. schinzii than to C. a. alpina. This corroborates the earlier genetic studies that Svalbard Dunlins are more closely related to arctica and schinzii than alpina.