Bonin Petrel (Pterodroma hypoleuca)

Bonin Petrel

[order] PROCELLARIIFORMES | [family] Procellariidae | [latin] Pterodroma hypoleuca | [authority] Salvin, 1888 | [UK] Bonin Petrel | [FR] Petrel des Bonin | [DE] Bonin-Sturmvogel | [ES] Petrel de las Bonin | [NL] Boninstormvogel

Subspecies

Genus Species subspecies Region Range
Pterodroma hypoleuca PO nw

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

Gray-black back and head. Forehead, chin, and throat white. Underparts white with partial gray collar extending from nape. Underwings white with dark margins and diagonal bar extending from carpal inward across coverts. Wedge-shaped tail. Flesh colored legs and feet with black toes. Length: 30 cm; wingspan: 63-71 cm.

Listen to the sound of Bonin Petrel

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

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 63 cm wingspan max.: 71 cm
size min.: 29 cm size max.: 31 cm
incubation min.: 48 days incubation max.: 50 days
fledging min.: 80 days fledging max.: 84 days
broods: 1   eggs min.: 1  
      eggs max.: 1  

Range

Pacific Ocean : Northwest. The Bonin Petrel disperses widely over the subtropical north Pacific, nesting on the Bonin and Volcano Island (Japan) and on the western Hawaiian Islands (USA).

Habitat

Bonin Petrels breed on low vegetated sandy islands throughout the Northwestern Hawaiian Islands, and disperse northwestward in the N Pacific after breeding.

Reproduction

Strictly nocturnal over breeding grounds. Monogamous. Return to same burrow every year. Adults arrive in August and spend the fall months courting, establishing pair bonds, excavating burrows, and nest building. Bonin Petrels nest in burrows that can be as long as three meters and one meter deep, usually in sandy areas. A single, white egg is laid in the nesting chamber at the end of the burrow. No relaying will take place if the egg is lost. Incubation duty is shared by both adults and lasts about 49 days. Chicks begin to hatch in early March. Parents feed chicks by regurgitating concentrated stomach oil (similar to Albatross). Parents average one feeding every two nights. Fledging occurs approximately 82 days after hatching. By the end of June, adults and chicks have departed the nesting colonies.

Feeding habits

Feed alone or in small groups, primarily at night. Feed on small fish and squid probably by dipping or surface-feeding. Occasionally associate with feeding Wedge-tailed Shearwaters, Sooty Terns, and Great Frigatebirds

Video Bonin Petrel

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

copyright: Peter Fraser


Conservation

This species has a very 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.
Bonin Petrel status Least Concern

Migration

Disperses widely over subtropical N Pacific, though some birds remain in warm waters to E of Japan; recorded N to Sakhalin.

Distribution map

Bonin Petrel distribution range map

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