South Georgia diving petrel

South Georgia diving petrel
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Procellariiformes
Family: Procellariidae
Genus: Pelecanoides
Species: P. georgicus
Binomial name
Pelecanoides georgicus
Murphy & Harper, 1916

The South Georgia diving petrel or Georgian diving-petrel (Pelecanoides georgicus) is one of four very similar small auk-like diving petrels of the southern oceans. It is native to the South Atlantic and islands of the southern Indian Ocean, New Zealand, and south-eastern Australia.

Taxonomy and nomenclature

The American ornithologist Robert Cushman Murphy and his partner Harper described the South Georgia diving petrel in 1916.[1] Its specific name, georgicus, is derived from the South Georgia islands where they identified the species. Other common names include puffinure de Géorgie du Sud (French), Breitschnabel Lummensturmvogel (German), and potoyunco de Georgia (Spanish).[2] The Codfish Island population in New Zealand diverged from the Indian Ocean populations several hundred thousand years ago and may be a distinct species.[3]

Description

The South Georgia diving petrel is a small, plump petrel, 180 to 220 mm (7.1–8.7 in) in length and weighing around 90 to 150 g (3.2–5.3 oz).[4] Its plumage is black above and dull white below, and it has a stubby black bill with pale blue edges.[5] The wings have thin white strips. The face and neck can be more brown than black. The legs are blue with posterior black lines down the tarsi.[5] Unless seen very close, it is almost indistinguishable from the common diving petrel; the common petrel has brown inner web primary feathers, whereas the South Georgia petrel has light inner web feathering. Common petrels have smaller and narrower bills than the South Georgia petrel,[5][6] and there are also slight size differences.[7]

Distribution and habitat

Pelecanoides georgicus (South Georgia diving petrel)
Pelecanoides georgicus on Sealer's Bay beach, Codfish Island/Whenua Hou, New Zealand.

This species nests in colonies on Subantarctic islands. It breeds on South Georgia in the south Atlantic and on the Prince Edward Islands, Crozet Islands, Kerguelen Islands and Heard Island and McDonald Islands in the southern Indian Ocean. In New Zealand, it breeds on Codfish Island, and formerly bred on the Auckland Islands and Stewart Island.[8] It disperses to surrounding seas and vagrants have been recorded in the Falkland Islands and Australia.[1] While 1.5 m (4.9 ft) nesting burrows are usually built on scree slopes above the vegetation line, they are occasionally built on flat land.[4][5] On Codfish Island in New Zealand, the population burrows into sand dunes at Sealers Bay.[9]

Behaviour

Egg of Pelecanoides georgicus

The South Georgia diving petrel feeds primarily on planktonic crustaceans, particularly krill, but will also feed on small fish and young cephalopods. Breeding season is October–February.[10] The female lays one egg that is incubated for 44–52 days. Fledging occurs in 43–60 days.[4] Threats to the South Georgia diving petrel include skuas, cats, rats, and weka. They became extinct on Auckland Island because Hooker's sea lions destroyed their nests,[4] and on Stewart Island becuse of kiore.[8] South Georgia diving petrels are noted for their diving capabilities: "The most proficient divers of the order Procellariformes are likely to be the diving petrels in the family Pelecanoididae."[11] Dive depths for the South Georgia diving petrel have been recorded to 48.6 m (159 ft), with most in the range of 20.4 to 24.4 m (67–80 ft).[11]

References

  1. 1 2 3 BirdLife International (2012). "Pelecanoides georgicus". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
  2. ↑ "South Georgia Diving Petrel (Pelecanoides georgicus)". Internet Bird Collection. Retrieved 5 June 2011.
  3. ↑ Paterson, Adrian M.; Wallis, L.J.; Wallis, G.P. (2000). "Preliminary molecular analysis of Pelecanoides georgicus (Procellariiformes : Pelecanoididae) on Whenua Hou (Codfish Island): implications for its taxonomic status". New Zealand Journal of Zoology. 27 (4): 415–423. doi:10.1080/03014223.2000.9518250.
  4. 1 2 3 4 "South Georgia Diving Petrel". Polar Conservation. Retrieved 5 June 2011.
  5. 1 2 3 4 Dewey, Tanya. "Pelecanoides urinatrix". Animal Diversity Web. Retrieved 5 June 2011.
  6. ↑ Brooke, Michael (2004). Albatrosses And Petrels Across The World. Oxford: Oxford University Press. pp. 428–430. ISBN 0-19-850125-0.
  7. ↑ "A Comparison Between Common and South Georgia Diving Petrels". Sea Birding. Retrieved 5 June 2011.
  8. 1 2 Holdaway, Richard N.; Jones, Martin D.; Beavan Athfield, Nancy R. (2003). "Establishment and extinction of a population of South Georgian diving petrel (Pelecanoides georgicus) at Mason Bay, Stewart Island, New Zealand, during the late Holocene". Journal of the Royal Society of New Zealand. 33 (3): 601–622. doi:10.1080/03014223.2003.9517748. Retrieved 29 July 2016.
  9. ↑ Taylor, G.A. (2013). Miskelly, C.M., ed. "South Georgia diving petrel". New Zealand Birds Online. Retrieved 29 July 2016.
  10. ↑ "South Georgia Diving Petrel Pelecanoides georgicus". BirdLife International. Retrieved 5 June 2011.
  11. 1 2 Prince, P. A.; M. Jones (1992). "Maximum dive depths attained by South Georgia Diving Petrel Pelecanoides georgicus at Bird Island, South Georgia" (PDF). Antarctic Science. 4 (4): 433–434. doi:10.1017/s0954102092000646. Retrieved 5 June 2011.
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