Fulmar Prion
The Thick-billed Petrel ( Pachyptila crassirostris ) is a species of the family of the petrels. It is a rather small members of this family, which can be observed only in the region of the southern oceans. There are two subspecies.
The IUCN classifies the Thick-billed Petrel as uncritical ( least concern ), since the range of the species is very large and the population numbers appear to be stable. The global population is estimated at 150.000 to 300.000 mature individuals.
Appearance
The Thick-billed Petrel reaches a body length of 24-28 inches. The wing length is 15.6 to 19 inches and the wingspan 60 centimeters. Thick -billed petrels weigh 102-185 grams. Males tend to be slightly larger than the females.
Compared with other representatives of the genus of the Thick-billed prions Petrel is relatively feathery pale. the body top is a pale blue-gray. About the wings runs as with all other prions a flashy, black gray "M". The Thick-billed Petrel also has a very broad black tail band. A dark gray eye-streak that runs through pale gray face. The face markings but overall is less conspicuous than is the case with other prions through this dark coloring. The body underside is white with pale brew sides of the chest. Young birds differ in their plumage not by the adult birds.
Confusion opportunities exist with the other species of the genus of prions. Is particularly marked resemblance to the Feensturmvogel.
Distribution area
The Thick-billed Petrel breeds on the snare Islands, Heard Island, the Auckland Islands, Bounty Islands and the Chatham Islands. The exact limits of its distribution outside the breeding season are unknown, however, the Thick-billed Petrel seems to reside mainly in the widths of its breeding islands. However, it was also observed before the south-eastern coast of Australia and off the coast of South Africa.
Way of life
The Thick-billed Petrel eats mainly small crustaceans and sticks while foraging near the coast. He is usually seen with both at sea and on land in swarms. These are monogamous birds with a long-term pair bond.
The Thick-billed Petrel breeds in crevices, in caves, in cavities in scree and boulders. The actual Nistmulde is lined with feathers and other materials. Most breeding Thick-billed petrels in dense colonies, often located in the vicinity of Albatross colonies. The nest consists of a single egg. This is white-skinned. The laying period falls in October and November. On the Bounty Islands, the chicks hatch usually from mid to late December. There are so far no studies, the age at which young birds fledge. It is a year removed when a large nest and both parents birds are involved in the breeding and care of the young bird.
Inside systematics
There are two subspecies:
- The nominate Pachytila crassirostris crassirostris breeds on the Chatham Islands, the snare islands and the Bounty Islands.
- The subspecies Pachytila crassirostris eatoni breeds on Heard Island and Auckland Islands. The subspecies is slightly smaller than the nominate race and has a slightly narrower beak.
A third subspecies Pachytila crassirostris pyramidalis is occasionally mentioned in the literature, but is not generally recognized.