Effects of Avian Biotransport of Industrial Wastes to a Bog Ecosystem

Big Meadow Bog, in the center of Brier Island, Nova Scotia, has long been the nesting site for American herring gulls (Larus smithsoniansus Coues), with recent counts of approximately 3000 pairs of birds at the colony in the summer. Gulls move from the colony to fish-processing plants, mink farms, aquaculture sites, and marine coastlines to feed, and then return to the colony to incubate their eggs or feed their chicks. These gulls defecate at the colony, regurgitate, and drop pieces of food; in some cases eggs, chicks, or adults die at the colony. These actions provide large nutrient and contaminant subsidies to the bog. Here we review information on this process of avian biotransport, and we examine evidence for amounts of nutrients and of mercury that birds contribute to the habitat.