Currently, monitoring data are insufficient to determine the Great Shearwater population status in Canada relative to about 1970. This species is a trans-equatorial migrant known to migrate to the North Atlantic Ocean off New Brunswick, Nova Scotia, Newfoundland, and Greenland for the non-breeding season. Two pelagic survey programs in Atlantic Canada conducted from 1969-1992 (PIROP; Programme Intégré de recherches sur les oiseaux pélagiques) and 2006-2018 (ECSAS; Eastern Canada Seabirds at Sea) indicate that this species is common in Canadian waters between May and November, peaking in August (Brown 1986, Fifield et al. 2009, C. Gjerdrum, Environment and Climate Change Canada, unpublished data). The average number observed per year is between 11,000 (PIROP) and 13,000 (ECSAS), but this number varies widely from less than 1,000 to over 60,000 individuals, likely owing to differences in survey coverage among years. The world population is estimated to be at least 15,000,000 birds (Brooke 2004), breeding almost exclusively on Gough, Nightingale, and Inaccessible Islands of Tristan da Cunha in the South Atlantic Ocean. Monitoring data at the colonies are not sufficient to detect any recent or historical changes in the species’ global population status, but populations are suspected to be stable (BirdLife International 2018i). Because of the lack of information, a national population goal for the Great Shearwater has not yet been determined.
