Wetland use by white-winged scoters (Melanitta fusca) in the Mackenzie Delta region

Abstract

Reasons for apparent declines in populations of white-winged scoters (Melanitta fusca) in the northern boreal forest are not well understood, but some evidence suggests factors associated with the breeding grounds may be responsible. Climate warming or increased forest fire frequency could adversely affect upland or wetland breeding habitats or key food sources for breeding females or ducklings, which in turn may lower productivity. However, very little is known about wetland habitat preferences of scoters. Determining what habitat features scoters need to breed successfully and whether changes in boreal forest breeding habitat affect scoter productivity are important steps towards understanding their ecology and developing appropriate conservation initiatives. Thus, our overall goal was to characterize features of wetlands used by scoter pairs and broods. Additionally, we compared features of wetlands surrounded by recently burned versus unburned forest to investigate whether fire-induced changes in wetland productivity, water chemistry, or amphipod abundance could affect patterns of scoter habitat use. Scoter pairs and broods used wetlands with more abundant amphipods, a finding that is consistent with other waterfowl studies. However, unlike some previous waterfowl studies, we did not find consistent positive correlations between total phosphorus levels and amphipod abundance or wetland use by scoters. We did not detect differences in our measured water chemistry variables, indices of wetland productivity, or amphipod abundance between wetlands surrounded by burned versus unburned forest.