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Sep 11 2011

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White-bellied Storm-petrel (Fregetta grallaria)

White-bellied Storm-petrel

[order] PROCELLARIIFORMES | [family] Hydrobatidae | [latin] Fregetta grallaria | [authority] Vieillot, 1817 | [UK] White-bellied Storm-petrel | [FR] Oceanite a ventre blanc | [DE] Weissbauch-Sturmschwalbe | [ES] Paino Ventriblanco | [NL] Witbuikstormvogeltje

Subspecies

Monotypic species

Genus

Storm-petrels are rather small and often dark colored tubenoses with a world wide distribution. All have fine black bills with very pronounced tubes. Storm Petrels are separated in two groups: the long legged, Southern Hemisphere birds subfamily Oceanitinae and the shorter legged species of more northern seas the subfamily Hydrobatinae. The first groups shows more morphological differences than the second. The genera are characterised on colour patterns, the condition of the nasal tubes, tail shape, structure of claws and proportions of the leg bones. The genus Fregetta have their plumage black above, white below and white upper tail coverts; nasal tube free at end and upturned, half culmen in length; tarsus booted in front, webs black, basal joint middle toe flattened, claws blunt and flattened.

Physical charateristics

A small, compact storm-petrel with a square cut tail, white forehead, face and underparts and a broad dark mark through the eye. Upperparts are dark grey. Various colour phases have been observed, including a dark phase, having sooty plumage, with only the rump and belly showing white.

Listen to the sound of White-bellied Storm-petrel

[audio:http://www.planetofbirds.com/MASTER/PROCELLARIIFORMES/Hydrobatidae/sounds/White-bellied Storm-petrel.mp3]

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 45 cm wingspan max.: 47 cm
size min.: 19 cm size max.: 20 cm
incubation min.: 0 days incubation max.: 0 days
fledging min.: 0 days fledging max.: 0 days
broods: 1   eggs min.: 1  
      eggs max.: 1  

Range

Southern Ocean : widespread. This species ranges widely over most oceans in the southern Hemisphere, breeding on Lord Howe Island (Australia), the Kermadec Islands (New Zealand), the Austral Islands (French Polynesia) and Juan Fernandez Islands, Chile in the Pacific Ocean, Tristan da Cunha and Gough Island (St Helena to UK) in the Atlantic Ocean, and Ile Saint-Paul (French Southern Territories) in the Indian Ocean.

Habitat

This marine species is highly pelagic and rarely approaches land except when near colonies. It forms loose colonies on offshore islands or stacks, generally amonst boulder scree or on grassy slopes up to 450 m above sea level, nesting in rock crevices or burrows

Reproduction

The White-bellied Storm-Petrel breeds in late summer and autumn. Eggs are laid from January to March, and the young fledge in May. It nests in crevices between large volcanic rocks, or in burrows excavated in banks. The nest chamber is sparsely lined with dried grass. It occurs at sea during the day, and returns to its breeding colonies at night. The young are fed by both parents on a mixture of crustaceans and squid.

Feeding habits

The White-bellied Storm-Petrel forages by skimming low over the ocean, sometimes pattering the water with its feet, and plucking small crustaceans and squid from beneath the surface of the water. It forages both at day and at night, usually far from shore.

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 very 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.
White-bellied Storm-petrel status Least Concern

Migration

Apparently disperses N to lower latitudes, but probably not as widely as F. tropica. In general, movements poorly known, as specific identification of these 2 species often very difficult, especially at sea.

Distribution map

White-bellied Storm-petrel distribution range map

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