Family Petrels, Shearwaters (Procellariidae)

Least Concern

Cory's Shearwater (Calonectris borealis)


French: Puffin cendré German: Corysturmtaucher Spanish: Pardela cenicienta canaria

Puffinus borealis


, 1881,

off Chatham Island, Massachusetts


Until recently considered conspecific with C. edwardsii (which see) and C. diomedea, differing from latter in its usually darker, browner head (1); more extensive dark tip of underwing (no white bases on primaries) (2); larger size, as expressed by mean wing length of males#R, effect size of 4·6 (score 2); calls delivered in threes vs twos, and in diomedea the notes are longer and with a high-pitched hiccup between them (2). Molecular evidence supports this split in one study#R, but is equivocal in another, with further research being called for#R. Monotypic.

What do (1) and (2) mean? Learn more about the scoring system.

E Atlantic, breeding from Galicia (NW Spain) and Berlengas Is (off WC Portugal) W to Azores and S to Canary Is; outside breeding season ranges widely in Atlantic, but wintering mainly in upwelling systems of the Benguela and Agulhas Currents#R. Has bred occasionally in Mediterranean (Columbretes, Giraglia)#R; population of Almería apparently of this species, based on both morphometric and genetic evidence#R.

Descriptive notes

48–56 cm; 605–1060 g; wingspan 113–124 cm. A large, bulky shearwater with a prominent yellowish bill. Flight style is characteristic, with slow, deliberate... read more


Vocalizes frequently at colonies, both in flight and on ground (including from within burrows),... read more


Marine and pelagic, usually keeping well away from land, except at colonies. Breeds on barren... read more

Food and feeding

Few if any known differences in diet and foraging behaviour from C. diomedea. In Azores, fish species taken are mainly small... read more


Very well studied. Starts Apr, although return to colonies starts in Feb, with pre-laying exodus averaging 19 days in females and just... read more


Migratory; regularly recorded mainly from Jul and Oct between Bay of Biscay and SW Ireland, with... read more

Status and conservation

Not globally threatened (Least Concern). Widespread and locally abundant, with total population numbering c. 600,000 birds, with a survey in 1996 recording 365,729... read more

Recommended citation

del Hoyo, J., Collar, N., Kirwan, G.M. & Garcia, E.F.J. (2018). Cory's Shearwater (Calonectris borealis). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 18 March 2018).