MONITORING WATERFOWL PRODUCTION IN FINLAND

Abstract

SUMMARY As a part of a nation-wide monitoring programme of waterfowl in Finland, yearly monitoring of breeding success (production of young) of most important game species was started in 1989. Broods are censused once each year between late June and mid July. Censuses are made by volunteer hunters using a standardized point count method. Between-year variation (1989–1997) of the production of the Mallard (Anas platyrhynchos), Teal (A. crecca), Wigeon (A. penelope) and Goldeneye (Bucephala clangula) was studied. Production was indexed as the product of number of broods and mean size of at least three weeks old broods. Production varied considerably between years in the three Anas species but was fairly stable in the Goldeneye. The size and, especially the number of broods, varied more in Teal and Wigeon than in Mallard and Goldeneye. In the Teal and Wigeon the number of broods varied more and also explained better than brood size the variation in production. No association was found between production and the number of breeding pairs in the same year in the four species. The production of young of Mallard, Teal and Goldeneye was studied also in a special study area in southern Finland. The number of broods observed in censuses in relation to the number of breeding pairs was highest in the Goldeneye and lowest in the Mallard. Due to differences in brood size, however, the number of young produced per pair was highest in the Teal and lowest in the Goldeneye.