White-chinned Petrel (Procellaria aequinoctialis)

White-chinned Petrel

[order] PROCELLARIIFORMES | [family] Procellariidae | [latin] Procellaria aequinoctialis | [authority] Linnaeus, 1758 | [UK] White-chinned Petrel | [FR] Puffin a menton blanc | [DE] Weisskinn-Sturmvogel | [ES] Pardela Gorgiblanca | [NL] Witkinstormvogel

Subspecies

Genus Species subspecies Region Range
Procellaria aequinoctialis SO widespread

Genus

The Procellaria petrels represent a group of large and bulky seabirds that can be placed between the shearwaters of the genus Calonectris and the more fulmarine petrels. Until recently the largest of the Procellaria-species, the White-chinned and the only slightly smaller Spectacled Petrel, were considered to be conspecific. Now they are split into two separate species. Both have a large and strong bills, ivory colored with black sulci between the horny plates and ivory colored ungues, the latter sometimes slightly darker in the Spectacled Petrel. The Westland and Parkinson?s Petrel are also two similar species, of which the latter is a smaller version of the first. Both have ivory colored bills (with a bluish tinge in young birds), with blackish ungues. In the Parkinson’s the black is less extensive than in the Westland. There is no overlap in bill measurements. The Westland Petrel is of the same size as the White-chinned and its culmen is always longer than 47.8 mm. That of the Parkinson?s Petrel not longer than 45.1 mm The bill of the somewhat distinct Grey Petrel is about the size of the larger Procellarias, with the same pattern as the White-chinned and pectacled, but instead of ivory, more pearl-grey. The Grey Petrel’s somewhat lighter bill structure comes close to that of the Calonectris species. Because its somewhat different coloration, habits and structure this species formerly formed a genus of its own: Adamastor. It is now considered to belong to Procellaria.

Physical charateristics

Large, black petrel with pale bill. Sooty-black with variable amount of white on throat and chin. Underside of primaries may appear silvery. Horn or yellow bill, with black between nostrils and bill tip. Largest all-dark shearwater or petrel. Bulkier than Westland Petrel P. westlandica and Black Petrel P. parkinsoni and lacks black bill tip. Spectacled Petrel P. conspicillata has diagnostic white eye-rings and dark tip to bill.

Listen to the sound of White-chinned Petrel

[audio:http://www.planetofbirds.com/MASTER/PROCELLARIIFORMES/Procellariidae/sounds/White-chinned Petrel.mp3]

Copyright remark: Most sounds derived from xeno-canto

recorded by Andrew Spencer


wingspan min.: 134 cm wingspan max.: 147 cm
size min.: 51 cm size max.: 58 cm
incubation min.: 57 days incubation max.: 62 days
fledging min.: 87 days fledging max.: 106 days
broods: 1   eggs min.: 1  
      eggs max.: 1  

Range

Southern Ocean : widespread. Procellaria aequinoctialis breeds on South Georgia (Georgias del Sur), Prince Edward Islands (South Africa), Crozet Islands, Kerguelen Islands (French Southern Territories), Auckland, Campbell and Antipodes Islands (New Zealand), and in small numbers in the Falkland Islands (Islas Malvinas).

Habitat

The White-chinned Petrel utilizes many islands during breeding season. 2,000,000 pair breed on South Georgia, Between 175,000 and 226,000 pair are on the Kerguelen Islands, and 100,000 pair on Disappointment Island. The Crozet Islands, Prince Edward Islands, Campbell Islands, Auckland Islands, Antipodes Island, and the Falkland Islands. During non-breeding season, these petrels fly from the Antarctic pack ice to the Subtopics

Reproduction

Both sexes help to build a nest, and will help incubate the egg. Upon hatching, both sexes again will assist in feeding and protecting the young. They start breeding in November/December in self-excavated burrows, on well-vegetated slopes and level ground. It lays one egg, incubated for about 57-62 days. The chicks fledge after 87-106 days.

Feeding habits

Birds avoid competition with other seabirds by ranging more widely when searching out food resources, travelling up to 8,000 km on feeding forays in the breeding season. Individuals breeding at the Crozet Islands display a bimodal foraging strategy, conducting either short trips to the surrounding shelf or long trips ranging from subtropical waters in the north to Antarctic waters in the south. White-chinned Petrels feed on cephalopods, crustaceans and fish.

Video White-chinned Petrel

httpv://www.youtube.com/watch?v=Fdc-Pb7rk0s

copyright: Brooke Clibbon


Conservation

This species is classified as Vulnerable because of suspected rapid declines, although almost no reliable estimates of historical populations exist. Very high rates of incidental mortality in longline fisheries are suspected in recent years; the probability that these circumstances will continue and its susceptibility to predation and loss of breeding habitat indicate a rapid and substantial population decrease is likely.
P. aequinoctialis constitute the majority of bird bycatch in Southern Ocean longline fisheries. It is one of the commonest species attending longline vessels off south-east Brazil during winter and constitutes virtually all the recorded seabird bycatch from the Namibian hake fishery. In South Africa, White-chinned Petrels constitute 10% and 55% of the bycatch in pelagic and demersal longline fisheries. Prior to the introduction of bird streamer lines as a vessel permit condition in August 2006, approximately, 10% of the 18,000 birds killed annually in the South African hake trawl fishery were White-chinned Petrels. In the Indian Ocean, between 2001 and 2003 the legal longline fishery for Patagonian toothfish Dissostichus eleginoides killed 12,400 P. aequinoctialis per year.
White-chinned Petrel status Vulnerable

Migration

Disperses widely over Southern Ocean, normally in zone c. 30 degrees to55 degrees S in Atlantic, Pacific and Indian Oceans; ranges N to c. 6 degrews S following cold waters of Humboldt Current, and to c. 20 degrees S following Benguela Current.

Distribution map

White-chinned Petrel distribution range map

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