Blue Petrel
Blue Petrel ( Halobaena caerulea)
The Blue Petrel ( Halobaena caerulea) is a monotypic species of the family of petrels ( Procellariidae ). It is a very small petrel, which has great similarity with the prions. A key distinguishing feature is the dark head cap that does not occur in prions.
The IUCN classifies the Blue Petrel as an 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 three million mature individuals.
Appearance
The Blue Petrel reaches a body length from 26 to 32 centimeters. The wing length is 19.8 to 23.3 inches and the wingspan from 62 to 71 centimeters. The weight of the blue petrels varies 152-251 grams. Males tend to be slightly larger and heavier than females.
Top and tail are blue-gray, vertex, neck and shoulder feathers are darker in comparison. Similar to the prions runs a dark "M" on the wings. The front head is mostly white with some dark speckles. The body underside is mostly white. The feet are blue and have flesh-colored webbed. Young birds have similar plumage as adult birds.
Voice
At sea, the blue petrel is mostly silent. In the breeding colonies, however, the adult birds can be heard especially during the night. Enter calls from himself, reminiscent of the vocalizations of birds. Onomatopoeic they are circumscribed with kuk - kuk - kuk coo - coo. There are at the call of the males geographical differences. In females, this has not been observed.
Distribution area
The Blue Petrel is found in the Antarctic waters. Very rarely you meet him further north than 40 ° on S. It breeds among other things, on the Prince Edward Islands, the Crozet Islands, Kerguelen and Macquarie and on the south by Chile. Outside the breeding season it is observed to the coasts of South Australia, New Zealand, southern South America and South Africa. However, the majority of the population adheres to all year round in the region of the breeding islands.
Way of life
The Blue Petrel eats crustaceans, fishes, cephalopods, and occasionally insects. While searching for food, he is frequently associated with prions and occasionally he also follows ships. He lives all year gregarious and nest in colonies.
Blue petrels nest in burrows dug itself a length of 15-37 centimeters. These are usually dug to gently sloping sea-facing slopes between tussocks. On the Kerguelen there seems to be a Nistplatzkonkurrenz with Belcher - petrels. The actual Nistmulde is occasionally covered with leaves and small twigs.
The reproductive period falls within the period from September to February. Spawning usually occurs during the period October. The nest consists of a single, white -shelled egg. The incubation period is 45 to 49 days. The young birds fledge after 43 to 60 days. Both parents birds are equally involved in the breeding as to the rearing of the young bird.
Like many other seabirds nesting in burrows also suffers the blue petrel at the introduction of mammals to their breeding islands. Rats have contributed to the number of breeding birds has declined significantly on the Macquarie. On Possession Iceland the breeding colonies are expired as a result of the introduced rats. Feral cats also have an effect on the breeding population at Kerguelen and Prince Edward Islands.
History of Research
The French doctor and naturalist Prosper Garnot reported in 1822 to have seen in the Falkland Islands a blue petrel. But there is no evidence that this species has ever bred in the Falkland Islands. Similar reports were also in later years, although already in the 1950s, ornithologists point out that this kind hatched certainly not in the Falkland Islands. In the observed birds are almost certainly always at Belcher - petrels of the genus prions that have the blue petrel great similarity.