Spatial and Temporal Variation in the Dietary Ecology of the Glaucous-winged Gull Larus Glaucescens in the Pacific Northwest

The widespread distribution of contaminants in marine environments is of global concern, particularly for those compounds that do not readily degrade and are relatively volatile, such as persistent organic pollutants (POPs) (Jones & De Voogt 1999, Tanabe 2004). POPs are a group of lipophilic compounds that accumulate in fatty tissues of organisms, leading to their bioaccumulation and biomagnification in marine food webs (Jones & De Voogt 1999, Tanabe 2004), with particularly high concentrations in piscivorous seabirds (Gilbertson et al. 1987, Furness & Camphuysen 1997, Gochfeld & Burger 2001, Becker 2003, Elliott & Elliott 2013). Accordingly, seabirds, including gull species, are integral components of several monitoring programs and provide data on trends, exposure pathways and effects of persistent contaminants (Newton et al. 1990, Elliott et al. 1989, 1992, 2005, Bignert et al. 1998, Hebert et al. 1999a, Becker et al. 2001, Braune 2007, Verreault et al. 2010, Fliedner et al. 2012, Burgess et al. 2013, Miller et al. 2014, 2015a, 2015b). One such program, the Great Lakes Herring Gull Monitoring Program, has successfully used the Herring Gull Larus argentatus since the early 1970s to track spatial and temporal trends in the distribution of many POPs (e.g. Norstrom et al. 1995, Hebert et al. 1999b, Gauthier et al. 2008, 2009). In 2006, the Environment Canada Chemical Management Plan (CMP) expanded annual gull monitoring to the national level, with the intention of tracking emerging contaminant trends in various gull species across Canada (Gebbink et al. 2011, SPATIAL AND TEMPORAL VARIATION IN THE DIETARY ECOLOGY OF THE GLAUCOUS-WINGED GULL LARUS GLAUCESCENS IN THE PACIFIC NORTHWEST