Mottled Petrel (Pterodroma inexpectata)

Mottled Petrel

[order] PROCELLARIIFORMES | [family] Procellariidae | [latin] Pterodroma inexpectata | [authority] Forster, 1844 | [UK] Mottled Petrel | [FR] Petrel de Peale | [DE] Regen-Sturmvogel | [ES] Petrel Moteado | [NL] Regenstormvogel

Subspecies

Genus Species subspecies Region Range
Pterodroma inexpectata PO, IO widespread

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

Medium-sized and distinctive petrel species, most easily identified by the grey patch on its lower breast and belly, which contrasts with the otherwise white underparts. The upperparts are grey, with a darker ?M’ shape across the back, rump and wings. The face is white, mottled with grey and with a dark patch behind the eye. The underside of the wing is white, with a broad black band running diagonally from the bend of the wing towards the body, and the tip and trailing edge of the underwing are dark.


wingspan min.: 0 cm wingspan max.: 0 cm
size min.: 33 cm size max.: 35 cm
incubation min.: 46 days incubation max.: 54 days
fledging min.: 90 days fledging max.: 105 days
broods: 1   eggs min.: 1  
      eggs max.: 1  

Range

Pacific Ocean, Indian Ocean : widespread. Pterodroma inexpectata is endemic to New Zealand. It breeds on islands off Fiordland, the Solander Islands, Foveaux Strait islands, islands around Stewart Island (including Titi islands, Codfish, Big South Cape Islands, and islets in Pacific Oceanrt Pegasus) and the Snares Islands

Habitat

It breeds in burrows on remote offshore islands and otherwise ranges widely at sea, outside the breeding season pelagic.

Reproduction

The nesting burrow is built in a various locations, but usually in contact with rock. The burrow extends for up to one meter and ends in an enlarged chamber, lined with grass. Breeding pairs usually stay together and use the same burrow from year to year. The female lays a single egg, which is incubated by both the male and female for around 50 days. Each incubation shift lasts between 12 and 14 days, giving the non-incubating adult time to travel huge distances to feeding grounds in the Antarctic. The newly hatched mottled petrel is covered in grey down and is brooded by the adults for one to two days, after which both adults forage and bring food back to the chick. The adults only return to the colony at night, possibly to avoid predation by the brown skua (Catharacta lonnbergi) . The young mottled petrel fledges at around 90 to 105 days old and departs from the colony by early June.

Feeding habits

The mottled petrel feeds mainly on squid, fish and some crustaceans, taking prey from or plunging just below the surface of the sea. It sometimes feeds in association with the sooty shearwater

Video Mottled Petrel

httpv://www.youtube.com/watch?v=BLw3WS96HP8

copyright: Peter Fraser


Conservation

This poorly known seabird breeds on only a few moderately small islands; on a number of these there are introduced predators and the population is therefore thought to be declining. It is consequently classified as Near Threatened.
Weka Gallirallus australis have been introduced to several colonies, and have caused significant losses on Codfish. Black rat Rattus rattus is present on Big South Cape Island, and may have a severe impact on breeding success. Some populations are on islands that are regularly harvested for Sooty Shearwater Puffinus griseus chicks, and the impact of trampling of burrows and incidental take is not known.
Mottled Petrel status Near Threatened

Migration

Transequatorial migrant. During breeding season, common S to pack ice zone near Antarctica; probably main foraging area for nesting adults. After breeding, quickly moves N to Bering Sea, where concentrates off Aleutian Is and in Gulf of Alaska; uncommon off W coast of N America. A few records off extreme S America, dating back to times when more abundant. One record from N Atlantic, off North Carolina, USA.

Distribution map

Mottled Petrel distribution range map

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