Effects of a severe winter on ducks breeding in north Somerset

Abstract

About 140 pairs of Mallard, 13 pairs of Shoveler and 120 pairs of Tufted Ducks attempted to breed at two reservoirs in Somerset in 1963. These numbers were 6%, 59% and 15% respectively lower than the average for the previous six years. Mallard were more numerous than in 1962. The reduced numbers of Shoveler and Tufted Ducks could well have been due to their exceptional lack of breeding success in 1962. Thus it is unlikely that the severe weather of December, 1962 to March, 1963 increased winter mortality in these populations. Breeding success in 1963 was unusually high.