All species › Tubenoses › Petrels, shearwaters and diving petrels › Sooty Shearwater
Sooty Shearwater | Ardenna grisea
Grauwe pijlstormvogel | Pardela sombría | Bobo-escuro
The Sooty Shearwater is a dark shearwater that breeds on islands in the southern oceans and outside the breeding season makes large loops across the Pacific and Atlantic. Over the cold Humboldt Current off Peru it gathers in flocks of thousands to hundreds of thousands of birds. It is one of the most numerous seabirds in the guide area.
Voice
Usually silent at sea; at feeding sites sometimes hoarse, cackling calls. At the breeding colonies moaning and cooing calls at night.
Recording: David Boyle — CC BY-NC-SA 4.0 · xeno-canto
Identification
43–46 cm, a slender, uniformly dark sooty-brown shearwater with narrow, somewhat swept-back wings, a short, rounded tail and a slender dark bill. The underwing coverts are silvery grey to whitish and form a pale panel along the middle of the underwing that flashes in flight. The legs are dark. It flies with fast, stiff wingbeats and short glides; in strong wind it arcs high above the water. The sexes are alike; juveniles resemble adults.
Confusion species
The dark morph of Wedge-tailed Shearwater Ardenna pacifica has a long, wedge-shaped tail, a dark underwing, a paler bill and a slower, relaxed flight. Black Petrel Procellaria parkinsoni and Westland Petrel Procellaria westlandica are more heavily built, with a blackish underwing without a pale panel and a pale bill with a dark tip. Pink-footed Shearwater Ardenna creatopus is larger and has white underparts and a pink bill.
Habitat
Cool, productive waters over the Humboldt Current, often within a few kilometres of the coast, also further out at sea. It feeds mainly on anchovies and other small schooling fish, also squid and krill; it dives to tens of metres and often hunts in large, dense flocks. It breeds in colonies in burrows on islands off New Zealand, southern Australia, southern Chile and the Falkland Islands.
Where the bird is most at home, classified by the vegetation units of the Andes and the west coast.
Range and movements
In Peru common to abundant off the entire coast, especially in the austral winter, and then often visible from shore. In Ecuador common at sea, especially off the south. In Colombia scarcer, off the Pacific coast, mainly as a passage migrant. Scarce around the Galápagos. Absent from Bolivia. It does not breed in the guide area. Outside the guide area it breeds in the southern oceans; outside the breeding season it migrates north into the North Pacific and North Atlantic.
- Resident
- Summer visitor (c. Apr–Sep)
- Passage (Mar–Apr, Oct–Nov)
- dark = core range, pale = thinly spread
How and when to look
In Peru from headlands and harbour piers, for example at Pucusana and Paracas, where long lines and dense flocks pass; on pelagic trips from Callao and other harbours year-round, with the largest numbers between May and September.
Conservation status
Near Threatened. The world population is still large but has declined in some colonies. Bycatch in fisheries, the traditional harvest of chicks in New Zealand, introduced predators on breeding islands and changes in food supply due to ocean warming are the main threats.
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. The genus name is a Late Medieval Latin name that Aldrovandi used in 1603 for the 'Diomedean birds'. Ardènna and Artènna are Italian dialect names for a shearwater, according to Capponi based on ardea, 'heron'. The species name comes from Medieval Latin griseus, 'grey'. The specimen the first description was based on came from New Zealand.