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Antarctic Prion | Pachyptila desolata
Antarctische prion | Prión Antártico
The Antarctic Prion is the most numerous prion of the Southern Ocean and in winter the prion most often seen off the Cape, sometimes in flocks of hundreds that sweep low and twisting over the waves.
Voice
Silent at sea. At the breeding sites a cooing, cackling koo-koo-kuk from the burrows at night.
Recording: Émile Brisson-Curadeau — CC BY-NC-SA 4.0 · converted to mono · xeno-canto
Identification
About 26 cm, a medium-sized prion with a round head. The upperparts are blue-grey with a clear black M across the wings. The head shows a dark eye-stripe, a white supercilium and fairly dark sides; on the side of the breast there is a prominent grey half-collar, often broader than in other prions. The underparts are white. The bill is blue, moderately broad and clearly narrower than in Salvin's Prion. The tail has a narrow to moderately broad black terminal band. It flies fast and erratically, often in large flocks.
Confusion species
Salvin's Prion (Pachyptila salvini) is slightly larger, with a broader bill; the two can rarely be separated with certainty at sea. Slender-Billed Prion (Pachyptila belcheri) is paler, with a narrower bill, a broad white supercilium and a weaker half-collar. Fairy Prion (Pachyptila turtur) is smaller and paler, with a much broader black tail tip. Blue Petrel (Halobaena caerulea) has a white tail tip.
Habitat
Cold Antarctic and subantarctic ocean, to the edge of the pack ice; in winter north over the cool waters of the Benguela Current. It feeds mainly on krill and copepods, fluttering or swimming at the surface. It breeds in burrows and crevices on subantarctic islands.
Where the bird is most at home, classified by the vegetation units of southern Africa.
Range and movements
In the region a winter visitor far off the Western and Southern Cape, in varying numbers and numerous in some years, scarcer east to KwaZulu-Natal and north off Namibia; sometimes washed up in numbers after storms. It does not breed on the Prince Edward Islands. Beyond the region it breeds on South Georgia, the South Orkney and South Shetland Islands, the Crozet, Kerguelen and Heard islands, Macquarie and the Auckland Islands.
- Winter visitor (c. Apr–Sep)
- dark = core range, pale = thinly spread
How and when to look
Winter pelagic trips from Cape Town to the trawlers on the continental shelf often produce prions, most of them Antarctic Prions. Photograph birds from above and from the side: bill width, half-collar and tail band together decide the identification. Dead birds on the tideline after a cold front make it possible to examine the species at close range.
Conservation status
Not threatened; with many millions of pairs one of the most numerous seabirds in the world. Locally introduced rats, cats and mice on the breeding islands are a threat, and in the long term so are changes in krill stocks caused by climate change.
Scientific name
Pachyptila desolata | (Gmelin, 1789)
Gmelin described the species in 1789 as Procellaria desolata; because it was later moved to another genus, the author and year stand in brackets. The genus Pachyptila was introduced in 1811 by Illiger. Pachyptila comes from the Greek pakhus, 'dense, thick', and ptilon, 'feather' — for the dense, soft plumage of the prions. desolata refers to Desolation Island, James Cook's name for the Kerguelen Islands, where the type specimen came from. The specimen the first description was based on came from Kerguelen Islands.