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Scopoli's Shearwater Calonectris diomedea

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Taxonomic source(s)
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.

Taxonomic note
Calonectris diomedea and C. borealis (del Hoyo and Collar 2014) were previously lumped as C. diomedea following Sibley and Monroe (1990, 1993), which was also formerly lumped with C. edwardsii following Hazevoet (1995), contra Brooke (2004).

Distribution and population
This species breeds in Algeria, Croatia, France, Greece, Italy, Malta, Spain (excluding the Canary Islands), Tunisia and Turkey (Derhé 2012). The majority of the population spends the non-breeding season in the Atlantic, including areas off the west coast of Africa and east coast of Brazil (Péron et al. 2012). The global population is thought to be in slow decline overall, although more research is required (Derhé 2012, Carboneras et al. 2013).

Population justification
The most recent assessment of the European population provided an estimate of 30,500-48,100 pairs, equating to 61,000-96,000 mature individuals (BirdLife International 2015). The population on Zembra Island, Tunisia is estimated at 113,720-176,750 pairs (Defos du Rau et al. 2012). The overall population has been estimated at 142,478-222,886 pairs (Derhé 2012, Carboneras et al. 2013), assumed here to be equivalent to c.285,000-446,000 mature individuals. This estimate follows recent surveys of the largest colony on Zembra Island, Tunisia, which resulted in an alternative revised estimate for the total breeding population of 179,000-193,000 pairs (Defos du Rau et al. 2012).

Trend justification
The overall population trend is estimated to be declining. The species's population is estimated and projected to be declining by c. 2% over three generations (1980-2038), although this is based on data from only 6% of the population (Derhé 2012, Carboneras et al. 2013). The European population is estimated to be declining by less than 25% in three generations (BirdLife International 2015). Estimates of adult survival and breeding probabilities in Tunisia are required to fully estimate the global population trend (Carboneras et al. 2013).

Pelagic movements are easily divided into frequent foraging trips around the breeding areas, rapid, long-distance migrations, and smaller-scale movements within a well defined wintering ground (González-Solís et al. 2007). Breeding starts in April on barren offshore islands, occupying cliffs, caves and boulder fields (del Hoyo et al. 1992). Diet is mostly squid, which are obtained mainly by surface-seizing. It is regularly attracted to trawlers to feed on offal (del Hoyo et al. 1992).

The main threats to the species include the impacts of invasive, non-native mammals and mortality from fisheries bycatch (Derhé 2012, Carboneras et al. 2013). Recent studies have highlighted the pressures imposed by introduced mammal species, and colonies have shown marked increases in breeding success during mammal control measures (e.g. Igual et al. 2006, Pascal et al. 2008). It is one of the most frequent seabird species to occur in bycatch in the Mediterranean (Valeiras and Caminas 2003, García-Barcelona et al. 2010, Laneri et al. 2010), with estimates of the number of individuals killed annually by Spanish fleets ranging from 200 (García-Barcelona et al. 2010) to 467-1,867 (estimated 4-6% of the local breeding population; Belda and Sanchez 2001). It is the main seabird species caught as bycatch by the Spanish long-line fleet in the western Mediterranean (Báez et al. 2014). Results from a questionnaire suggest an annual bycatch of up to 1,220 individuals by Maltese fleets (8.5-10% of the breeding population), although this is likely to be an over-estimate skewed by high bycatch in a small number of vessels (Dimech et al. unpubl. per Derhé 2012). The species may also suffer significant bycatch in its non-breeding range (e.g. Granadeiro et al. 2006). Light pollution has been identified as a further threat (Rodríguez et al. 2015).

Báez, J.C, García-Barcelona, S., Mendoza, M., Ortiz de Urbina, J.M., Real, R. and Macías, D. 2014. Cory's shearwater by-catch in the Mediterranean Spanish commercial longline fishery: implications for management. Biodiversity and Conservation 23: 661-681.

Belda, E. J.; Sanchez, A. 2001. Seabird mortality on longline fisheries in the western mediterranean: factors affecting bycatch and proposed mitigating measures. Biological Conservation 98: 357-363.

Brichetti, P.; Foschi, U. F.; Boano, G. 2000. Does El Niño affect survival rate of Mediterranean populations of Cory's Shearwater? Waterbirds 23: 147-154.

Brooke, M. de L. 2004. Albatrosses and Petrels Across the World. Oxford University Press, Oxford.

Carboneras, C.; Derhé, M.; Ramirez, I. 2013. Update on the population status and distribution of Mediterranean shearwaters. Report to Seventh Meeting of the ACAP Advisory Committee, La Rochelle, France, 6-10 May 2013.

Defos du Rau, P.; Bourgeois, K.; Ruffino, L.; Dromzée, S.; Ouni, R.; Abiadh, A.; Estève, R.; Durand, J-P.; Anselme, L.; Faggio, G.; Yahya, J.M.; Peters, P.; Rguibi, H.; Renda, M.; Miladi, B.; Hamrouni, H.; Alilech, S.; Ben Dhafer, A.; Nefla, A.; Jaouadi, W.; Agrebi, S.; Renou, S. 2012. New assessment of the world largest colony of Scopoli's Shearwater Calonectris diomedea. In: Yésou, P.; Baccetti, N.; Sultana, J. (ed.), Ecology and Conservation of Mediterranean Seabirds and other bird species under the Barcelona Convention - Proceedings of the 13th Medmaravis Pan-Mediterranean Symposium. Alghero (Sardinia) 14-17 Oct. 2011, pp. 26-28. Medmaravis, Alghero.

del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International.

del Hoyo, J.; Elliot, A.; Sargatal, J. 1992. Handbook of the Birds of the World, vol. 1: Ostrich to Ducks. Lynx Edicions, Barcelona, Spain.

Derhé, M. 2012. Developing a Population Assessment for Scopoli's and Cory's Shearwaters Calonectris diomedea/Calonectris borealis. In: Yésou, P.; Baccetti, N.; Sultana, J. (ed.), Ecology and Conservation of Mediterranean Seabirds and other bird species under the Barcelona Convention - Proceedings of the 13th Medmaravis Pan- Mediterranean Symposium. Alghero (Sardinia) 14-17 Oct. 2011, pp. 29-38. Medmaravis, Alghero.

García-Barcelona, S.; Ortiz de Urbina, J. M.; de la Serna, J. M.; Alot, E.; Macias, D. 2010. Seabird bycatch in Spanish Mediterranean large pelagic longline fisheries, 2000-2008. Aquatic Living Resources 23: 363-371.

Gonzalez-Solis, J., Felicisimo, A., Fox, J.W., Afanasyev, V., Kolbeinsson, Y. and Munoz, J. 2009. Influence of sea surface winds on shearwater migration detours. Marine Ecology Progress Series 391: 221-230.

Granadeiro, J. P.; Dias, M. P.; Rebelo, R.; Santos, C.D.; Catry, P. 2006. Numbers and population trends of Cory's Shearwater Calonectris diomedea at Selvagem Grande, Northeast Atlantic. Waterbirds 29: 56-60.

Hazevoet, C. J. 1995. The birds of the Cape Verde Islands. British Ornithologists' Union, Tring, U.K.

Igual, J.M.; Forero, M. G.; Gomez, T.; Orueta, J. F.; Oro, D. 2006. Rat control and breeding performance in Cory's Shearwater (Calonectris diomedea): effects of poisoning effort and habitat features. Animal Conservation 9(1): 59-65.

IUCN. 2015. The IUCN Red List of Threatened Species. Version 2015-4. Available at: (Accessed: 19 November 2015).

Navarro, J. and Gonzales-Solis, J. 2009. Environmental determinants of foraging strategies in Cory's shearwaters Calonectris diomedea. Marine Ecology Progress Series 378: 259-267.

Péron, C.; Grémillet, D.; Culioli, J.-M.; Faggio, G.; Gillet, P.; Mante, A.; Vidal, P. 2012. Exploring marine habitats of two shearwater species breeding on French Mediterranean islands. In: Yésou, P.; Baccetti, N.; Sultana, J. (ed.), Ecology and Conservation of Mediterranean Seabirds and other bird species under the Barcelona Convention - Proceedings of the 13th Medmaravis Pan-Mediterranean Symposium. Alghero (Sardinia) 14-17 Oct. 2011, pp. 19-25. Medmaravis, Alghero.

Pascal, M.; Lorvelec, O.; Bretagnolle, V.; Culioli, J. M. 2008. Improving the breeding success of a colonial seabird: a cost-benefit comparison of the eradication and control of its rat predator. Endangered Species Research 4: 267--276.

Rodríguez, A., García, D., Rodríguez, B., Cardona, E., Parpal, L. and Pons, P. 2015. Artificial lights and seabirds: is light pollution a threat for the threatened Balearic petrels? Journal of Ornithology DOI: 10.1007/s10336-015-1232-3.

Sibley, C.G. and Monroe, B.L. 1990. Distribution and Taxonomy of Birds of the World. Yale University Press, New Haven, USA.

Sibley, C.G. and Monroe, B.L. 1993. A supplement to 'Distribution and Taxonomy of Birds of the World'. Yale University Press, New Haven, USA.

Valeiras, J.; Caminas, J. A. 2003. The incidental capture of seabirds by Spanish drifting longline fisheries in the western Mediterranean Sea. Scientia Marina 67: 65-68.

Further web sources of information
Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Butchart, S., Calvert, R., Ekstrom, J., Newton, P., Symes, A., Taylor, J. & Ashpole, J

IUCN Red List evaluators
Symes, A.

Recommended citation
BirdLife International (2016) Species factsheet: Calonectris diomedea. Downloaded from on 31/05/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from on 31/05/2016.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Cory's shearwater (Calonectris diomedea) 0

Key facts
Current IUCN Red List category Least Concern
Family Procellariidae (Petrels, Shearwaters)
Species name author (Scopoli, 1769)
Population size 285000-446000 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 45,000,000 km2
Country endemic? No
Links to further information
- Additional Information on this species
- 2015 European Red List assessment