Factors related to breeding production of Brent Geese Branta b. bernicla and waders (Charadrii) on the Taimyr Peninsula

There are large cyclic variations in the breeding success of Brent Geese; we have examined 3 hypotheses in an attempt to explain these. Spring feeding conditions play no more than a minor role in causing variations: 3 species of wader, arriving on the Taimyr Peninsula by different routes and having different diets from the geese, have similar and correlated variations in breeding success to the geese. With respect to weather on the breeding grounds, goose production was not correlated with precipitation but it was correlated with March and June temperatures. The strongest correlations of goose breeding success were with lemming abundance, either within a given year or when a lag effect was introduced. These results are consistent with the hypothesis that predators, 'uch as Arctic Foxes, which usually eat lemmings when they are available, switch to birds in years when lemming numbers are low.