Iceland Gulls breed in the Canadian High Arctic, where no large-scale, systematic surveys monitor their abundance. The population is potentially increasing in abundance in Greenland (Petersen et al. 2008). Surveys of eastern Baffin Island in the 1970s and 1980s suggest a relatively unchanged abundance over this period (Gaston and Nettleship, unpublished data). Surveys at three colonies in Digges Sound documented a 39% increase in abundance between 1980 and 2009 (Gaston et al. 1985; Gaston and Smith, unpublished data). A small colony at Coats Island, Nunavut, thought to have been established between 1975 and the 1990s, now holds some 75 pairs (Gaston and Ouellet 1997). Colony counts up to 2009 suggest no substantial changes in the abundance of L. g. thayeri in the southwestern Foxe Basin (Gaston, A.J., M.L. Mallory, and H.G. Gilchrist, ECCC, unpublished report); this area may support one third of the global population of this subspecies. The species is common along both the Pacific and Atlantic coasts in winter, so results are available from the Christmas Bird Count (CBC) and the British Columbia Coastal Waterbird Survey (BCCWS). However, results from the two surveys are contradictory; the CBC suggests a large increase continentally since 1970, while the BCCWS suggests a large decrease since 1999. While the North American CBC results likely represent birds that breed in Canada, a large proportion of birds do not move out of the Arctic, so only a small fraction of the population is being surveyed. The BCCWS is short-term, and restricted to southern British Columbia, so it is unclear whether its results are representative of the larger population. These surveys may also be unreliable for Iceland Gull because the numbers sighted could be influenced by an increasing tendency for birds to use developed coastal habitats, such as lawns and garbage dumps. Overall, given the limitations in temporal and geographic scope of the surveys during the breeding season, and the limitations and uncertainties tied to the wintering surveys, there is currently insufficient information to assess the status of the Iceland Gull population in Canada relative to 1970. As such, a national population goal for this species has not yet been determined.
Additional information on: Christmas Bird Count (CBC)
Additional information on: British Columbia Coastal Waterbird Survey
