Movements and migrations of WigeonAnas penelopewintering in Britain and Ireland

Abstract

The paper describes an analysis of 1419 recoveries of Wigeon ringed in Britain and Ireland and 401 recoveries in that area of foreign-ringed birds. They result from ringing carried out from the early part of the century to January 1986. Most of it took place in SE England, in Essex, Suffolk and Norfolk. Most recoveries were of shot birds. The recoveries had 1.5 males per female, a proportion which was similar to that in the population at large. The median time between ringing and recovery was 771 days for males and 567 days for females, suggesting a higher survival rate of males. This supports the hypothesis that the imbalance in the sex-ratio occurs because females lose out in competition for food. The Wigeon wintering in southern Britain mainly breed between Scandinavia and central Siberia, especially in the basins of the Ob and Pechora rivers. Birds passing through and wintering in northern England and Scotland mostly breed in Iceland. A proportion of both stocks moves on to winter in Ireland. Males migrate before females in autumn, along a direct route from the breeding area. In spring, the route is more southerly and there is an important staging area in the Tula and Ryazan steppes, southeast of Moscow. The populations of Iceland, northwest Europe and of the Black Sea and Mediterranean have different flyways but there is considerable mixing. There is substantial turnover of Wigeon in Britain during the winter, as early arrivals are shot or pass through into Ireland. The number of Wigeon using Britain during the winter is probably half as much again as is present at the peak, which is usually in January. More work is needed to provide accurate estimates. There is also an urgent need to assess the relationship between sites within Britain and between Ireland and Britain, so that we can assess autumn dispersal and, in particular, hard weather movements of Wigeon.