Bonin petrel
| Bonin petrel | |
|---|---|
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| On Midway Atoll | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Procellariiformes |
| Family: | Procellariidae |
| Genus: | Pterodroma |
| Species: | P. hypoleuca |
| Binomial name | |
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Pterodroma hypoleuca (Salvin, 1888) |
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The Bonin petrel (Pterodroma hypoleuca) is a seabird in the family Procellariidae. It is a small gadfly petrel. The species is native to the North Pacific Ocean. Its secretive habits, remote breeding colonies and limited range have resulted in few studies and many aspects of the species' biology are poorly known.
The Bonin petrel is a small gadfly petrel, 30 cm long with a wingspan of around 67 cm. It has a white head with a black cap and face markings; overall the head often has a scaled appearance. Its pale grey upperparts have darker primaries and wing coverts creating an "M" mark across the back. The underwing is white with dark edging and a patch at the carpal joint and across underwing coverts. The tail is dark grey, and the rest of the plumage is white, except for a dark half collar on the breast. Like the rest of the Pterodroma petrels the black bill is short and hooked. The legs and feet are pink with dark patches.
The Bonin petrel is currently thought to be closely related to the mottled petrel and white-necked petrel in the subgenus Proaestrelata, based on a review of the whole Pterodroma genus looking at morphology, calls, breeding biology, diet and parasitic lice. Despite the species having two remote and separate breeding localities the species is monotypic and no subspecies are recognised.
995,000 individuals, about 99% of the total population, breed on the Northwestern Hawaiian Islands, while 5,000 individuals (1% of the population) breed off the coast of Japan on the Bonin and Volcano Islands.
The Bonin petrel and the closely related mottled petrel are the only Pterodroma petrels with a fish dominated diet. Principal prey items are fish from the family Myctophidae (lantern fish) and Sternoptychidae (hatchetfish). Squid from the family Ommastrephidae are also consumed. All of these prey are midwater residents that use photophores and migrate to the surface during the night to feed; thus it is assumed that Bonin petrels are nocturnal feeders that seize prey at the surface while resting on the sea or in flight. Bonin petrel eyes contain high levels of the pigment rhodopsin which aids nocturnal vision. The Bonin petrel is usually solitary at sea, but is occasionally seen in large multi-species flocks. Like all procellariids the Bonin petrel has a modified area of the gut known as a proventriculus which partly digests prey to create stomach oil, an energy rich oil which is lighter to carry than prey.
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Wikipedia