Procellaria di Westland

Identificazione

The adult Westland petrel is a stocky bird, weighing around 1,100 grams (39 oz). It is entirely dark blackish-brown, with black legs and feet. Some individuals may have a few white feathers. The bill is pale yellow with a dark tip. Falla measured the female and male birds for his original description and pointed out that the male of the species measured slightly larger than the female. However the female specimen weighed slightly more than the male. It is one of the largest of the burrowing petrels.<p>Falla described the eggs of this species as follows:<p>These were white, smooth, without gloss and generally similar to the eggs of most other petrels. They vary in shape from elongate pyriform to ovate. The average weight of the entire egg when fresh is about 4 oz.

Tassonomia

The Westland petrel was first described by New Zealand ornithologist Robert Falla in 1946 under the name Procellana parkinsoni westlandica. The Westland petrel was identified in 1945 after the students of Barrytown School wrote to Falla, as he was then the director of the Canterbury Museum. They had heard in a radio broadcast about the sooty shearwater/muttonbird, but noticed that the behaviour of the 'mutton birds' in their area was quite different. They also sent Falla a dead bird, and within a few weeks he visited the West Coast. Initially he considered that the West Coast birds were a subspecies of the black petrel (Procellaria parkinsoni), but it was soon classified as a separate species. The male holotype specimen, collected at Barrytown on 29 April 1946, is held at the Canterbury Museum.<p>The Māori name is tāiko, which also refers to the black petrel, Procellaria parkinsoni.

Nome scientifico

Procellaria westlandica

Autorità

Falla, 1946

Ordine

Procellariformi

Famiglia

Procellaridi

Genere

Procellaria

Areale e habitat

The Westland petrel is endemic to New Zealand. It spends most of its life at sea, only returning to land to breed, and breeds only in a small region of the South Island's West Coast. The breeding range covers an 8 km (5.0 mi) wide strip between Barrytown and Punakaiki, specifically from the Punakaiki River to Waiwhero (Lawson) Creek. The area of the breeding colonies comprises forest-covered coastal foothills within the Paparoa National Park, or other conservation land, or on land belonging to Forest And Bird. There is also a breeding colony located on private land. The total area of all breeding colonies combined is only about 16 hectares (40 acres).<p>During the breeding season, adults may be seen in waters around New Zealand from Cape Egmont to Fiordland in the west, through the Cook Strait, and from East Cape to Banks Peninsula in the east. Westland petrels also range across areas of the Pacific Ocean and Tasman Sea around the subtropical convergence. In the non-breeding season, the birds migrate east to waters off South America and feed in the Humboldt Current. They are often found in waters to the west of the Chilean coast. Individuals usually remain solitary during this time, rejoining the colony when the next breeding cycle begins.

Areale riproduttivo

PO : coastal foothills of Paparoa Range, nw South I. (New Zealand)

Areale non riproduttivo

to se Australian waters and Humboldt Current of se Pacific from n Chile to Cape Horn (s Chile)

Migrazione

Complete migrants

Conservazione

As of 2021, this species is regarded as being endangered under the International Union for Conservation of Nature Red List of Threatened Species. The Department of Conservation assessed its conservation status in 2021 as "At Risk: Naturally Uncommon" under the New Zealand Threat Classification System.<p>During the fledging season, a team of local conservationists patrol an 8 km (5.0 mi) section State Highway 6 in the Barrytown Flats area that lies beneath the flight path from the breeding colonies, looking for birds that have crash-landed on or near the road. Any birds that are found are placed in a box and delivered to the Department of Conservation office in Punakaiki. Each bird gets a checkup, and is then released from a cliff.

Tendenza della popolazione

unknown