The sooty shearwater (Ardenna grisea) is a medium-large shearwater in the seabird family Procellariidae. In New Zealand, it is also known by its Māori name , and is harvested by Māori people for muttonbird, like its relatives the wedge-tailed shearwater (A. pacificus) and the Australian short-tailed shearwater (A. tenuirostris).

Taxonomy

The sooty shearwater was formally described in 1789 by the German naturalist Johann Friedrich Gmelin under the binomial name Procellaria grisea. The shearwater had been briefly described in 1777 by James Cook in the account of his second voyage to the Pacific, but without a valid scientific name; and also in 1785 the English ornithologist John Latham had described a museum specimen, again without giving it a scientific name. The sooty shearwater is now placed in the genus Ardenna, that was described in 1853 by Ludwig Reichenbach. The genus name Ardenna was used to refer to a seabird by Italian naturalist Ulisse Aldrovandi in 1603, and the specific epithet grisea is medieval Latin for "grey". The species is considered to be monotypic; no subspecies are recognised.

Description

thumb|left|Up close, the chocolate-coloured [[plumage can be appreciated. Kaikōura, New Zealand.]]

Sooty shearwaters are in length with a wingspan.

In the Atlantic, it is the only all-dark large shearwater, though can be confused with the smaller and usually somewhat paler Balearic shearwater at long range; the latter does not have the pale stripe on the underwing. may be seen flying back north up the British east coast as they retrace their path back to the Atlantic over northern Scotland.

Ecology and status

The sooty shearwater feeds on fish and squid. They can dive up to 68 m deep for food,

They breed in huge colonies and the female lays one white egg, which on average measures 48mm (1.7 in.) in width and 77.5mm (3.1 in.) in length. These shearwaters nest in burrows lined with plant material, which are visited only at night to avoid predation by large gulls and skuas. The architecture of sooty shearwater burrows can vary within and between breeding colonies, and is influenced by competition for breeding space and habitat type, with soil under dense tussac grass being easier to excavate than other substrates.

In New Zealand, about 250,000 chicks are harvested for muttonbird for oils and food each year by the indigenous Māori population. Young birds just about to fledge are collected from the burrows, plucked, and often preserved in salt. In 2022, climate change was thought to be impacting this cultural harvest by Ngāi Tahu.

Its numbers have been declining in recent decades, and it is presently classified as near threatened by the IUCN. were sighted on the shores of North Monterey Bay in California, regurgitating anchovies, flying into objects, and dying on the streets. The incident sparked the interest of local resident Alfred Hitchcock, along with a story about strange bird behaviour by the British writer Daphne du Maurier, helping to inspire Hitchcock's 1963 thriller The Birds, a cautionary tale of nature revolting against man. The film is now ranked among the American Film Institute's top-10 thrillers of the last century.

Scientists looking at the stomach contents of turtles and seabirds gathered in 1961 Monterey Bay ship surveys found that toxin-making algae were present in 79% of the plankton the creatures ate. "I am pretty convinced that the birds were poisoned," says ocean environmentalist Sibel Bargu of Louisiana State University. "All the symptoms were extremely similar to later bird poisoning events in the same area."

Plankton expert Raphael Kudela of USC points to leaky septic tanks installed amid a housing boom around Monterey Bay in the early 1960s as the ultimate culprit that may have fed the toxic algae: "It is to some extent a natural phenomenon, and the best thing we can do is monitor for the presence of toxins, and treat impacted wildlife."

==References==<!-- AnnualReviewOfEcologyEvolutionAndSystematics37:637. BulletinOfTheBritishOrnithologistsClub129:129. -->

Further reading

  • Bull, John L.; Farrand, John Jr.; Rayfield, Susan & National Audubon Society (1977). The Audubon Society field guide to North American birds, Eastern Region. Alfred A. Knopf, New York. <small></small><!-- 1984 is reprint -->
  • Harrison, Peter (1988). Seabirds (2nd ed.). Christopher Helm, London. <small></small>
  • Gillson, Greg (2008). Field separation of Sooty and Short-tailed Shearwaters off the west coast of North America Birding 40(2): 34–40.
  • Sooty shearwater – Species text in The Atlas of Southern African Birds.
  • Sooty shearwater photos
  • BTO BirdFacts – sooty shearwater
  • The Titi Project: Website of a long-term sooty shearwater research project in New Zealand . Recovered 2006-NOV-20
  • NPR: "The Common Shearwater, Nature's Migration King". Day to Day, aired August 8, 2006. Recovered 2006-NOV-20
  • TerraNature "The incredible journey of sooty shearwater from New Zealand to the north Pacific for an endless summer" 25 April 2007
  • Tītī – muttonbirding in Te Ara – the Encyclopedia of New Zealand
  • A Seaweed Pantry – Tales from Te Papa episode 100 – a short video on muttonbirding