All species › Tubenoses › Petrels and shearwaters › Great Shearwater
Great Shearwater | Ardenna gravis
Grote pijlstormvogel | Pardela capirotada
A large, contrasting shearwater with a dark cap that breeds on the Tristan da Cunha islands and circles the North Atlantic in the northern summer. In the region a scarce autumn visitor far off the Moroccan coast, officially still treated as a vagrant to Morocco.
Voice
Usually silent at sea, but when squabbling over fish waste behind boats a sharp, screaming and quacking eeyah. At the colony loud moaning at night.
Recording: Sven Normant — CC BY-NC-SA 4.0 · converted to mono · xeno-canto
Identification
Large and powerful, with long, straight wings. A sharply defined dark brown cap reaching below the eye contrasts with a white throat and an almost complete white collar. Upperparts grey-brown with pale fringes, giving a scaly pattern; a narrow white band across the uppertail coverts stands out against the dark tail. Underparts white with a dark belly patch and dark undertail coverts; the underwing is white with dark lines across the coverts and a dark trailing edge. The bill is long, slender and black. Flies strongly with stiff beats and long glides; readily follows fishing boats.
Confusion species
Scopoli’s Shearwater (Calonectris diomedea) and Cory’s Shearwater (Calonectris borealis) are duller and plainer, without a sharp cap or white collar, with a pale yellow bill and a slower, more flexible flight. Manx Shearwater (Puffinus puffinus) is much smaller and cleanly black and white. Balearic Shearwater (Puffinus mauretanicus) is smaller and browner and lacks the cap and the rump band.
Habitat
Open ocean, especially over the continental shelf and shelf edge; follows fishing boats and whales. Breeds in burrows among tussock grass on remote southern islands.
Where the bird is most at home, classified by the habitats of North Africa and the Middle East.
Range and movements
In the region only off Morocco’s Atlantic coast, where it is a regular but scarce passage migrant offshore while remaining rare close inshore; the Moroccan Rare Birds Committee still officially treats it as a vagrant. The largest numbers have been seen off Agadir: 65 in the bay on 6 November 2011 and 32 on a pelagic trip on 30 October 2017; otherwise singles and groups of two to four, mainly from September to November. Probably more regular off Western Sahara, but those waters are barely watched. An exceptional vagrant in the Mediterranean. Beyond the region it breeds almost entirely on Tristan da Cunha and Gough Island, with a small colony in the Falklands; in the southern winter it moves north through the western Atlantic and returns down the eastern side in autumn.
- Summer visitor (c. Apr–Sep)
- Passage (Mar–Apr, Oct–Nov)
- dark = core range, pale = thinly spread
How and when to look
Pelagic trips from Agadir in October and November are by far the best chance; from land it is only to be expected at Cap Rhir and in Agadir bay in stormy weather. Look for a big shearwater with a dark cap and a white collar.
Conservation status
Not globally threatened, with millions of pairs on Gough and Tristan da Cunha; on Gough introduced mice eat chicks, and longline bycatch is a threat. In the region a scarce passage migrant of no conservation significance.
Scientific name
Ardenna gravis | (O'Reilly, 1818) (GBIF: Puffinus gravis)
O'Reilly described the species in 1818 as Procellaria Gravis; because it was later moved to another genus, the author and year stand in brackets. The genus Ardenna was introduced in 1853 by Reichenbach. Ardenna goes back to Artenna, the spelling the Italian naturalist Ulisse Aldrovandi used for a seabird in 1603 and which Reichenbach cited when naming the genus. gravis is Latin for 'heavy' or 'weighty'. The specimen the first description was based on came from Cape Farewell, Greenland.