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Cory's Shearwater | Calonectris borealis
Kuhls pijlstormvogel | Pardela cenicienta atlántica
Cory's Shearwater breeds on islands in the eastern Atlantic, from the Azores and Madeira to the Canary Islands and the Berlengas off Portugal. Outside the breeding season it ranges widely across the Atlantic, in the northern summer reaching waters off the east coast of North America. In the Caribbean it is a rare visitor far offshore and does not breed.
Voice
Almost silent at sea. At the colonies, loud, raucous wailing and cackling calls at night.
Recording: Sven Normant — CC BY-NC-SA 4.0 · converted to mono · xeno-canto
Identification
45–56 cm. A large, heavily built shearwater with long, broad wings held slightly bowed and swept back. The flight is relaxed, with slow, flexible beats and long glides in wide arcs. Upperparts grey-brown with paler fringes; head and sides of neck grey-brown, merging without a sharp border into the white throat, with no cap. Underparts white. Underwing white with a narrow dark border; the primaries are largely dark below, with at most short white tongues. The bill is stout and yellow with a dark band before the tip. Some show a narrow pale band across the uppertail coverts. The sexes are alike; males average heavier-billed.
Confusion species
Scopoli's Shearwater Calonectris diomedea averages smaller and slimmer, with a finer bill; below, the white extends as long tongues far into the primaries, reaching the outermost one. Without a good photograph of the underwing many birds remain unidentified. Great Shearwater Ardenna gravis has a sharply defined dark cap, a white collar, a white horseshoe above the tail, a dark belly patch, a dark bill and a stiffer flight with quicker beats.
Habitat
Open sea, often over the edge of the continental shelf and over deep water. It eats fish, squid and crustaceans, often where dolphins or predatory fish drive shoals to the surface, and also follows fishing boats. It breeds in burrows and rock crevices on islands and cliffs.
Where the bird is most at home, classified by the vegetation types of the Caribbean.
Range and movements
A rare visitor at sea, almost only far offshore. Documented records are few and scattered, including from waters around the Bahamas and the Lesser Antilles. The first documented record for Dominica was a bird in December 2002. The range map shows presence mainly in the northern summer; these are non-breeding birds. Older reports often did not separate it from Scopoli's Shearwater. Beyond the region it breeds on the Azores, Madeira, the Selvagens, the Canary Islands and the Berlengas. After breeding most birds move to the South Atlantic; in the northern summer it is regular off the east coast of the United States.
- Summer visitor (c. Oct–Mar)
- dark = core range, pale = thinly spread
How and when to look
A chance exists almost only on pelagic trips or seawatches from projecting headlands, mainly in late spring and summer. Photographs of the spread underwing are needed to exclude Scopoli's Shearwater.
Conservation status
Not threatened. On the breeding islands introduced rats and cats play a part, and fledglings are disoriented by artificial light. At sea birds die as bycatch in longline fisheries. No regular presence in the Caribbean.
Scientific name
Calonectris borealis | (Cory, 1881) (GBIF: Calonectris diomedea)
Cory described the species in 1881 as Puffinus borealis; because it was later moved to another genus, the author and year stand in brackets. The genus Calonectris was introduced in 1915 by Mathews & Iredale. Calonectris combines the Ancient Greek kalos 'good, noble' with the genus name Nectris, used for shearwaters by the German naturalist Heinrich Kuhl in 1820. borealis is Latin for 'northern'. The specimen the first description was based on came from off Chatham, Massachusetts.