Data in Canada are not sufficiently reliable to determine a change in population status relative to about 1970 for Short-tailed Shearwaters occurring in Canadian waters. The total global population of Short-tailed Shearwaters may exceed 30,000,000 birds, with a breeding population of perhaps 11,500,000 pairs (Skira et al. 1996, Brooke 2004). This species is notoriously difficult to differentiate at-sea from Sooty Shearwaters, and consequently, the number of Short-tailed Shearwaters identified in Canada’s Pacific waters has likely been underestimated. Short-tailed Shearwaters have been encountered in Canada in every month. Off the coast of British Columbia (and Washington), Short-tailed Shearwaters are most numerous in May and June and again in September through mid-November (Campbell et al. 1990a, Kenyon et al. 2009, Wahl et al. 2005). Generally, this species is widely distributed in Canadian Pacific waters at low densities in both nearshore and offshore areas (Kenyon et al. 2009). However, Campbell et al. 1990a reported that huge concentrations have been encountered off the southwest coast of Vancouver Island, as well as on both the east and west coasts of Haida Gwaii. Because of the lack of information, a national population goal for the Short-tailed Shearwater has not yet been determined.
