Evidence that fidelity to natal breeding colony is not absolute in female snow geese

Abstract

A sharp increase in population size, a lower than expected proportion of marked birds, and the utilization of new nesting areas led to the hypothesis that there was a large number of nonnative female snow geese breeding at La Pérouse Bay, Man., in 1978. Evidence is presented that the unmarked birds nesting in the new area differ significantly from the rest of the colony in clutch size and initiation date. The alternate hypothesis, that there was extraordinary recruitment from the young of the colony in 1978, is shown to have consequences in contradiction to the data.