Elevated mercury levels in a declining population of ivory gulls in the Canadian Arctic

摘要

The ivory gull (Pagophila eburnea) is a high Arctic marine bird which is in serious population decline for reasons unknown. Local ecological knowledge interviews and colony surveys indicate an 80% decline in numbers of nesting ivory gulls in Arctic Canada since the early 1980s (Gilchrist and Mallory, 2005). Ivory gulls feed largely on fish and invertebrates, but also scavenge placentae, faeces and carrion of marine mammals (Haney and MacDonald, 1995). Given their relatively high trophic position in marine food webs (Hobson et al., 2002), contaminants have been proposed as one stressor which could be affecting this species.