All species › Tubenoses › Petrels, shearwaters and diving petrels › Sooty Shearwater
Position in the tree Birds Aves › Birds with a flexible palate Neognathae › All other modern birds Neoaves › Birds of the elements Elementaves › Tropicbirds and waterbirds Phaethoquornithes › Core waterbirds Aequornithes
Sooty Shearwater | Ardenna grisea
Grauwe pijlstormvogel | Pardela sombría
The Sooty Shearwater is one of the most numerous seabirds in the world. It breeds in the southern hemisphere and in the southern winter migrates in great loops through the Pacific and Atlantic Oceans to the north and back again. In the guide area it is a regular passage migrant and summer visitor, mainly off the Pacific coast of Baja California, sometimes in large flocks.
Voice
Almost silent at sea; sometimes harsh sounds when competing for food. In the colony moaning and cooing calls at night.
Recording: David Boyle — CC BY-NC-SA 4.0 · shortened to the first 60 s, mono · xeno-canto
Identification
40–51 cm. A large, entirely dark shearwater with long, narrow wings set well back, a fairly short body and a short tail. The plumage is dark chocolate brown, slightly paler below. The underwing coverts form a silvery-grey to whitish band along the middle of the underwing, which flashes when the bird banks. Bill long, slender and dark; legs dark. Flies with quick, stiff wingbeats and long glides, in strong wind in high arcs. Sexes alike.
Confusion species
Dark morph Wedge-tailed Shearwater Ardenna pacifica has a uniformly dark underwing, a long, pointed tail, flesh-coloured legs and a calm, floating flight. Black Petrel Procellaria parkinsoni has a pale bill with a dark tip and flies more slowly. Christmas Shearwater Puffinus nativitatis is smaller, with a dark underwing. Dark jaegers such as Pomarine Jaeger Stercorarius pomarinus have broader wings with a white patch at the base of the primaries.
Habitat
Open ocean, both over deep water and over the continental shelf, sometimes also close inshore; occasionally follows ships. Eats fish, squid and krill, taken at the surface or caught in dives to depths of tens of metres. Breeds in burrows on vegetated islands in the southern hemisphere.
Where the bird is most at home, classified by the vegetation units of Mexico and Central America.
Range and movements
Mainly off the Pacific coast of Baja California, where in spring and summer large flocks sometimes pass or feed; also in the mouth of the Gulf of California. Further south along the Pacific coast to Panama a scarcer passage migrant, mainly far offshore. Rare in the Gulf of Mexico and on the Caribbean side. Outside the guide area the species breeds around New Zealand and southern Australia, in southern Chile, around Tierra del Fuego and on the Falkland Islands, and migrates through the Pacific and Atlantic Oceans into subarctic waters.
How and when to look
Seawatching from headlands and pelagic trips off the west coast of Baja California in spring and summer offer the best chance. An entirely dark shearwater with a silvery central band on the underwing and a stiff, fast wingbeat is almost certainly this species.
Conservation status
Near Threatened. The world population still numbers many millions of birds, but has declined in recent decades. Causes include bycatch in fisheries, the harvest of chicks in New Zealand and changes in food supply due to ocean warming.
Scientific name
Ardenna grisea | (Gmelin, 1789) (GBIF: Puffinus griseus)
Gmelin described the species in 1789 as Procellaria grisea; 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. grisea is medieval Latin for 'grey'. The specimen the first description was based on came from New Zealand.