Cory's Shearwater
(Calonectris diomedea)


Picture of bird
© Ian N White - License
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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.


Main designations for the species
DesignationStatusDateSubspecies, population
IUCN (Global)Least concern2018 
Partners in Flight (North America)Watch list - yellow R2017 
Wild Species (Canada)Not applicable2015 
State of North America’s BirdsWatch list2016 
Bird Conservation Region StrategyPriority Species2013 

Population status

Geographic area or populationPopulation change relative to ~1970ReliabilityStatus in relation to goal
CanadaData DeficientData DeficientData Deficient

Population estimate

Geographic area or populationPopulation estimate
CanadaNot yet available

Distribution maps


Migration strategy, occurrence

Seasonal visitor

Responsibility for conservation

Geographic areaResponsibility based on % of global population
CanadaVery Low

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.

BCRs, marine biogeographic units, and sub-regions in which the species is listed as a priority
RegionSub-region and priority type
Newfoundland and Labrador Shelves Newfoundland and Labrador Shelves , sub-region and priority type: Atlantic, NL -- Other
Scotian ShelfScotian Shelf, sub-region and priority type: Atlantic, NS -- Conservation