Soft-plumaged Petrel (Pterodroma mollis)

Soft-plumaged Petrel

[order] PROCELLARIIFORMES | [family] Procellariidae | [latin] Pterodroma mollis | [authority] Gould, 1844 | [UK] Soft-plumaged Petrel | [FR] Petrel soyeux | [DE] Weichfeder-Sturmvogel | [ES] Petrel Suave | [NL] Donsstormvogel

Subspecies

Genus Species subspecies Region Range
Pterodroma mollis SO IO, AO

Genus

Genus Pterodroma, Pseudobulweria and Aphrodroma are also knwon as the Gadfly Petrels. They vary in size from rather small birds such as the Cookilaria-species, measuring about 26 cm, to the much larger and robust representatives of this group like the White-headed Petrel with an overall length of about 43 cm. Their plumages also vary a great deal from species to species; from completely black to light grey mantles and pure white bellies, and with different color phases within species. One feature shared by all of them is the black bill of which the shape also shows much variation. Some species are extremely rare and restricted to a very limited area, other are abundant and wander widely or have unknown pelagic ranges.
The group of the Gadfly Petrels counts over 35 species, mainly from the Southern Hemisphere. There are three genera: Pterodroma with about 30 species, Pseudobulweria counting four and Aphrodroma with only one. Many authors have tried to classify the large number of species of this group and to determine their relationships. This has resulted in a division in several subgenera and the grouping of several species which are considered to have a more or less close relationship. The taxonomic discussion has not come to an end yet: new species have been added or split recently and probably will be in the near future.

Physical charateristics

Intermediate in size and structure between Zino?s and Fea?s Petrels, sharing heavy bill with latter species. Counterpart in southern oceans of Fea?s Petrel, normally differing distinctly in complete dusky band round upper breast and darker, dusky, not pale grey tail, contrasting far less with dark rump. On well-marked birds, breast band restricts white throat which may not show at long range, unlike Zino?s and Fea?s Petrels, but beware some birds showing incomplete or paler breast band. On some birds, underwing less uniformly dark than northern congeners, with mainly white larger coverts, pale bases to primaries and secondaries restricting solidly black areas to band along outer primaries, carpal panel and band sloping back from carpal joint to centre of wing-pit. Pattern of head similar to Fea?s Petrel, lacking full dark hood of Zino?s Petrel.


wingspan min.: 83 cm wingspan max.: 95 cm
size min.: 32 cm size max.: 37 cm
incubation min.: 49 days incubation max.: 51 days
fledging min.: 88 days fledging max.: 51 days
broods: 1   eggs min.: 1  
      eggs max.: 2  

Range

Southern Ocean : Indian Ocean, Atlantic Ocean. The Soft-plumaged Petrel breeds on islands in the Southern Hemisphere, nesting on Tristan da Cunha and Gough Island (St Helena to UK), the Prince Edward Islands (South Africa), Crozet Islands (French Southern Territories) and on the Antipodes Islands (New Zealand). It disperses outside the breeding season, reaching eastern South America north to Brazil, South Africa, Australia and New Zealand

Habitat

Pelagic and marine in subtropical to Antarctic southern oceans coming near land only at breeding colonies; tolerates wide range of water temperatures. Nests colonially in burrows on steep slopes, usually on coast but sometimes in inland valleys, often in dense ground vegetation. Remains mainly in lowest airspace at sea, soaring to c. 20 m in high winds. Gregarious, at times in loose flocks of up to 1000; sometimes follows ships.
It breeds in burrows on well-vegetated ledges at 1,600 m. Birds return to their breeding grounds in late March or early April. A single egg is laid mid-May to early June and young fledge in late September or early October. Breeding success on one ledge has improved since the 1980s, with a total of eight chicks fledged in 1993. Its diet probably consists of small squid and fish. Rat populations in the breeding area have decreased since 1986 as a result of poisoning regimes

Reproduction

Starts Sep.Colonial; nests in long burrows ( burrow can be occupied by two pairs.
1 egg. Incubation 50 days.

Feeding habits

Mostly cephalopods, also crustaceans and some fish.
Prey apparently taken mainly by surface-seizing. Occasionally follows ships and cetaceans

Video Soft-plumaged Petrel

httpv://www.youtube.com/watch?v=FXTeWNgtnFA

copyright: P. Fraser


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). The population trend appears to be stable, and hence the species does not 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.
Not globally threatened. Total population thought to number tens of thousands of breeding pairs
Soft-plumaged Petrel status Least Concern

Migration

Poorly known; wanders over South Atlantic and Indian Ocean generally north of c. 60 degrees S, dispersing towards but rarely entering tropics; young birds probably move further than adults. Returns to colonies around September-October, eggs laid November-December and disperses into ocean April-June. Occurs off eastern South America, southern Australia, and southern Africa in southern winter. Some populations perhaps sedentary, for example recorded around Amsterdam Island all year. No definite records in northern hemisphere apart from Dead Sea individual.

Distribution map

Soft-plumaged Petrel distribution range map

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