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The species breeds widely across Canada, where a large portion of its breeding population is well covered by the Breeding Bird Surveys(BBS). Results from the BBS suggest that the population in Canada has exhibited a large increase in abundance since about 1970. The species has also expanded its range to the north and west (Sirois et al. 1995, Pollet et al. 2012). However, although the abundance in Canada remains well above 1970s levels, recent censuses of colonies in the Great Lakes report a 26% decline in the abundance of Ring-billed Gulls between 1999 and 2009. This decline is partly attributable to direct management of populations considered over-abundant at several locations (Morris et al. 2011; see Conservation and Management).
Additional information on: Breeding Bird Survey (BBS) - Canadian analysis
Additional information on: Great Lakes Decadal Colonial Waterbird Census
View numerical data of the graph.