Population structure and origins of Purple Sandpipers Calidris maritima in north Norway during winter

Wintering Purple Sandpipers Calidris maritima were captured at Varangerfjorden, Finnmark, in March 1992, and compared with samples from Troms county in November 1988 to describe the population structure in north Norway in terms of age and sex classes, and to determine the origins of these wintering birds. The overall percentage of first-year birds was 35% at Varangerfjorden, higher than that in Troms (21%). However, there may have been biases in the catches at Varangerfjorden, and the percentage in the largest catch was 23% first-year. In both regions, the percentage of first-year birds varied among sites, indicating age segregation. There was a higher percentage of males than females in the first-year population at Varangerfjorden and in both age classes at Troms. The wing and bill lengths of the different age/sex classes at Varangerfjorden and Troms were similar, indicating largely similar origins. Comparison of bill and wing lengths of wintering birds with samples from the breeding grounds supports results from ringing data that the wintering birds come predominantly from Russia, but with some also from Svalbard.

Karl-Birger Strann, Ron W. Summers and Rab Rae, Ringing & Migration (2006) 23, 95-100