The geography of diet: diversity in diet and foraging behavior in herring gulls (Larus argentatus) across Atlantic Canada
University of New Brunswick
Changes in food availability are thought to be the primary driver of Herring Gull (Larus argentatus) species decline, but empirical evidence linking gull diet to population dynamics is lacking. First, I test the ability of new GPS tracking technology to provide representative data on Herring Gull movement, analyzing the effect of tag deployment on adult behavior and reproductive output. I found that effects were short-term. Secondly, I analyze data from GPS tags deployed on Herring Gulls at two colonies in the Bay of Fundy, Canada, and combine results with those from a more established diet methodology, stable isotope analysis. I found that variation in individual foraging strategy is high, but colony-level differences in diet and foraging location do emerge. This study provides the foundation for understanding how differences in individual foraging strategy may lead to variation in individual reproductive success and the ability to adapt to a changing environment.