Antarctic Prion (Pachyptila desolata)

Antarctic Prion

[order] PROCELLARIIFORMES | [family] Procellariidae | [latin] Pachyptila desolata | [authority] Gmelin, 1789 | [UK] Antarctic Prion | [FR] Prion la Desolation | [DE] Tauben-Sturmvogel | [ES] Pato petrel Antartico | [NL] Antarctische Prion

Subspecies

Genus Species subspecies Region Range
Pachyptila desolata SO, AN widespread

Genus

Prions are a race of abundant small petrels from the Antarctic and subantarctic region with very similar plumages: a white body, bluish grey upperparts with a dark M on the back and upper sides of the wings when seen from above. Although there is considerable difference in measurements, the main difference between the species lies in the shape of the bills. These vary from small ‘pointed’ via ‘fulmarish’ to extreme broad. Characteristic are the lamellae along the sides of the palate in all species. These form a sieving structure to filter small food particles from the water. The development of these lamellae and grooves vary depending on the species. Bills of all Prions are bluish, except in the Broad-billed which has a blackish bill. Identification of the Prions at sea is very difficult. Therefore much of the pelagic distribution is unknown.
The taxonomy of the Prions is difficult and possibly not yet fully understood. It is mainly based on size and structure of the bill. But since there is a lot of intraspecific variability and intergradation between the recognized species and subspecies, the discussion on this topic is not closed yet. The list below shows the seven species that are accepted generally, including the recent separation of the MacGillivrayi’s Prion.

Physical charateristics

They are distinctively patterned black-and-white on their upperparts, while their underparts are mostly white. The chin and throat are blackish and the tail has a blackish tip. The underwing is white with black margins, and the bill, legs and feet are all black.


wingspan min.: 80 cm wingspan max.: 91 cm
size min.: 35 cm size max.: 42 cm
incubation min.: 43 days incubation max.: 47 days
fledging min.: 43 days fledging max.: 45 days
broods: 1   eggs min.: 1  
      eggs max.: 1  

Range

Southern Ocean, Antarctica : widespread. They have a circumpolar distribution that ranges from the subtropics to the edge of the Antarctic continent. Cape Petrels breed on numerous islands surrounding the coasts of Antarctica and on sub-Antarctic islands. A few pairs nest as far north as New Zealand’s Auckland Islands, the Chatham Islands and Campbell Island; the majority of the species nest further south. The species’ stronghold is on the Antarctic Peninsula and the islands of the Scotia Sea. They also breed on other sites on the Antarctic mainland, as well as South Georgia, the Balleny Islands, and Kerguelen Island.

Habitat

Pelagic, breeding on slopes under grass.

Reproduction

Antarctic prion arrive at their colonies in October to early November. They nest on exposed rock faces of cliffs, in cavities under boulders or in short twisting burrows in soft grass-covered slopes. Experienced breeders are the first to appear, and often return to the same site they used the previous year. The females will leave the nesting site for approximately 14 days before laying, but the males will reappear at night keeping the nest hole free from snow. One egg is laid in December, and hatches in late January to mid-February. The egg is incubated by both members of the pair for a total of 45 days. The male takes the first shift. Departure of the chicks and adults occurs in mid-March, 45-55 days after hatching. Adults and fledglings move into subantarctic and temperate waters for the winter months, regularly reaching Australia

Feeding habits

Antarctic prion feed on euphausiids and other crustaceans, small cephalopods and polychaete worms. They feed by running along the surface of the water with wings outstretched and bill (or their entire head) submerged in the water to scoop their food. They also take larger individual prey from the surface in flight or while swimming. They occasionally make shallow dives to capture prey.

Video Antarctic Prion

httpv://www.youtube.com/watch?v=2BFS7ToIFz8

copyright: Greg Baker


Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Antarctic Prion status Least Concern

Migration

All birds leave colonies after breeding, probably moving N; disperses widely over S Atlantic and S Indian Oceans, from pack ice to subtropical latitudes off S America, where recorded N to 12? S off Peru; also occurs off S Africa and Australia.

Distribution map

Antarctic Prion distribution range map

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