Cory's Shearwater
(Calonectris diomedea)

Overview

Summary

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Cory’s Shearwaters breed on remote islands of Portugal and Spain in the North Atlantic, and winter predominantly off the coast of South America and southern Africa. Wintering birds are also known to occur regularly but in low numbers in the warm waters of the Gulf Stream, making them a regular visitor to Canada’s Scotian Shelf (ECCC 2017f). Reliably assessing changes in the number of Cory’s Shearwaters travelling and foraging in Canadian waters relative to 1970 is not possible with available survey data. However, at-sea surveys conducted since 2006 suggest that densities have increased in the waters off the coast of Nova Scotia since 2007 (Gjerdrum et al. 2018). With less than 1% of the population occurring in Canadian waters, Canada’s conservation responsibility for this species is very low. This species has been identified as a priority for conservation and/or stewardship in one or more Bird Conservation Region Strategies in Canada.

Designations

Population status

Population estimate

Distribution maps

• eBird Canada 2018

Migration strategy, occurrence

Responsibility for conservation

Conservation and management

Cory’s Shearwaters, like many pelagic seabirds, are attracted to fishing vessel offal and baited hooks, which are a substantial cause of incidental mortality to both breeding and wintering birds (Granadeiro et al. 2006). This species is also vulnerable to oiling from accidental hydrocarbon releases throughout its marine range. The Eastern Canada Seabirds at Sea (ECSAS) Monitoring Program provides current data and information on Cory’s Shearwater abundance and distribution in Canadian waters (see Gjerdrum et al. 2012, ECCC 2017f). These data provide critical information for environmental assessments related to offshore developments, emergency response related to oil spills, risk assessments, marine protected area planning, and other management and conservation initiatives.

Bird conservation region strategies

Environment and Climate Change Canada and partners have developed Bird Conservation Region Strategies in each of Canada’s Bird Conservation Regions (BCRs). In these strategies, selected species are identified as priorities for one or more of the following reasons:

• conservation concerns (i.e., species vulnerable due to population size, distribution, population trend, abundance, or threats)
• stewardship responsibilities (i.e., species that typify the regional avifauna or have a large proportion of their range or population in the sub-region)
• management concerns (i.e., species that require ongoing management because of their socio-economic importance as game species, or because of their impacts on other species or habitats)
• other concerns (i.e., species deemed a priority by regional experts for other reasons than those listed above or because they are listed as species at risk or concern at the provincial level)

Select any of the sub-regions below to view the BCR strategy for additional details.

References

• Brown, R.G.B. 1986. Revised Atlas of Eastern Canadian Seabirds. Canadian Wildlife Service, Ottawa, Ontario. 111 pp.
• Environment and Climate Change Canada (ECCC). 2017f. Atlas of Seabirds at Sea in Eastern Canada 2006-2016. Environment and Climate Change Canada (ECCC). 2017f. Atlas of Seabirds at Sea in Eastern Canada 2006-2016. (Link)
• Gjerdrum, C., D.A. Fifield, and S.I. Wilhelm. 2012. Eastern Canada Seabirds at Sea (ECSAS) standardized protocol for pelagic seabird surveys from moving and stationary platforms. Canadian Wildlife Service Technical Report Series No. 515. Atlantic Region. vi + 37 pp. Gjerdrum, C., D.A. Fifield, and S.I. Wilhelm. 2012. Eastern Canada Seabirds at Sea (ECSAS) standardized protocol for pelagic seabird surveys from moving and stationary platforms. Canadian Wildlife Service Technical Report Series No. 515. Atlantic Region. vi + 37 pp. (Link)
• Gjerdrum, C., J. Loch, and D.A. Fifield. 2018. The recent invasion of Cory's Shearwaters into Atlantic Canada. Northeastern Naturalist 25(4):532-544. Gjerdrum, C., J. Loch, and D.A. Fifield. 2018. The recent invasion of Cory's Shearwaters into Atlantic Canada. Northeastern Naturalist 25(4):532-544. (Link)
• Granadeiro, J.P., M.P. Dias, R. Rebelo, C.D. Santos, and P. Catry. 2006. Numbers and populations trends of Cory’s Shearwater Calonectris diomedea at Salvagem Grande, Northeast Atlantic. Waterbirds 29:56-60. Granadeiro, J.P., M.P. Dias, R. Rebelo, C.D. Santos, and P. Catry. 2006. Numbers and populations trends of Cory’s Shearwater Calonectris diomedea at Salvagem Grande, Northeast Atlantic. Waterbirds 29:56-60. (Link)