Shy albatross

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Shy albatross
Thalassarche cauta - SE Tasmania.jpg
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Procellariiformes
Family: Diomedeidae
Genus: Thalassarche
Species: T. cauta
Binomial name
Thalassarche cauta
(Gould, 1841)[2]
Over pelagic waters off the southeast coast of Tasmania

The shy albatross or shy mollymawk (Thalassarche cauta) is a medium-sized albatross that breeds off Australia and New Zealand's subantarctic islands and ranges extensively across the Southern Ocean.

Some authorities call this species the white-capped albatross.[3]

Taxonomy[edit]

This mollymawk was once considered to be the same species as the Salvin's albatross, Thalassarche salvini and the Chatham albatross, Thalassarche eremita, but they were split around 2004. In 1998, Robertson and Nunn suggested a four-way split including the white-capped albatross, Thalassarche steadi.[4] The three-way split was accepted by Brooke in 2004,[5] the ACAP in 2006,[6] SACC in 2008,[7][8][9] and BirdLife International by 2000.[10] James Clements seems to be the last major holdout on the three-way split.[11] The fourth split, steadi, was only accepted by the ACAP in 2006,[6] and BirdLife International in 2008.[10] Finally, following Brooke, this species was shifted from Diomedea to Thalassarche, which was generally agreed upon by most experts.

Mollymawks belong to the albatross family, Diomedeidae, which shares the order Procellariiformes with shearwaters, fulmars, storm petrels, and diving petrels. Procellariiformes have certain identifying features. They have nasal passages that attach to the upper bill, called naricorns (although the nostrils on the albatross are on the sides of the bill). The bills are also unique in that they are split into between seven and nine horny plates. They produce a stomach oil made up of wax esters and triglycerides that is stored in the proventriculus. This is used against predators as well as an energy-rich food source for chicks and for the adults during their long flights.[12] They also have a salt gland that is situated above the nasal passage and helps desalinate their bodies, required due to the high amount of ocean water that they imbibe. It excretes a high saline solution from their nose.[13]

Description[edit]

The shy albatross averages 90 to 99 centimetres (35–39 in) in length, 220–256 cm (87–101 in) wingspan,[14] and 4.1 kg (9.0 lb) in weight. Alongside its similarly sized sister species, the Salvin's albatross, this species is considered the largest of the mollymawks or the small albatrosses.[15][16] It is a black, white and slate-grey bird with the characteristic black thumb mark at the base of the leading edge of the underwing. Adults have a white forehead and a crown, which is bordered on the bottom with a dark eyebrow and pale grey face. Its mantle, tail and upperwing are grey-black, and the rest is white. Its bill is grey-yellow with a prominent yellow culmen and yellow tip.[17]

Behavior[edit]

Shy albatross frequently follow fishing boats

Feeding[edit]

The shy albatross feeds by a combination surface-seizing and some pursuit diving – it has been recorded diving as deep as 5 m (16 ft). Fish, cephalopods, crustacea, and tunicates are the sustenance for this species.[18]

Reproduction[edit]

The shy albatross breeds on rocky islands and builds mounded nests of soil, grass, and roots. They lay one egg in the second half of September.[5]

Range and habitat[edit]

Breeding population and trends[17]
Location Population Date Trend
Albatross Island 5,017 pairs 2007 Increasing 3% per yr
Mewstone 7,258 — 7,458 pairs 1996
Pedra Branca 268 pairs 1996 Decreasing 10% per yr
Total 26,000 2007 Unknown

The shy albatross is endemic to Australia and it breeds on three island colonies; Albatross Island, Pedra Branca, and the Mewstone.[19] During the breeding season, adults concentrate around southern Australia and Tasmania.[20][21][22][23] Juvenile birds are known to fly as far as South Africa;[22][23] otherwise, non-breeding birds can be found throughout the southern oceans, but specifics are hard to determine due to their similarity to the other species.[6][24] It is sometimes found off the Pacific coast of the United States.

Conservation[edit]

The IUCN classifies this species as near threatened,[1] with an occurrence range of 23,900,000 km2 (9,200,000 sq mi). The population from an estimate in 2007 was 25,500 breeding birds with 5,100 pairs on Albatross Island, 270 pairs on Pedra Branca, and 7,380 on the Mewstone.[17] Historically, they were exploited for their feathers, and by 1909 there were only 300 pairs left on Albatross Island.[5][25]

Today, longline fishing still impacts this species but their numbers have been maintained despite this threat.[23] They also had an avian pox outbreak on Albatross Island that has impacted their numbers slightly.[26] Finally, the Australasian gannet, Morus serrator is the primary threat to their survival.[6]

Footnotes[edit]

  1. ^ a b BirdLife International (2012). "Thalassarche cauta". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013. 
  2. ^ Brands, S. (2008)
  3. ^ Remsen Jr., J. V. (2008)(a)
  4. ^ Robertson, C. J. R. & Nunn, G. B. (1998)
  5. ^ a b c Brooke, M (2004)
  6. ^ a b c d ACAP (2006)
  7. ^ Remsen Jr., J. V. (2004)
  8. ^ Remsen Jr., J. V. (2005)
  9. ^ Remsen Jr., J. V. (2008)
  10. ^ a b BirdLife International (2008b)
  11. ^ Clements, J. (2007)
  12. ^ Double, M. C. (2003)
  13. ^ Ehrlich, Paul R. (1988)
  14. ^ Dunn, Jon L. & Alderfer, Jonathan (2006)
  15. ^ "Save the albatross: Shy albatross". The RSPB. 
  16. ^ Brooke, Michael, Albatrosses and Petrels across the World (Bird Families of the World). Oxford University Press (2004), ISBN 978-0-19-850125-1
  17. ^ a b c BirdLife International (2008a)
  18. ^ Hedd, A. & Gales, R. (2001)
  19. ^ Brothers, Nigel (2001). Tasmania's Offshore Islands: seabirds and other natural features. Tasmanian Museum and Art Gallery. ISBN 0-7246-4816-X. 
  20. ^ Hedd, A., et al. (2001a)
  21. ^ Garnett, S. T. & Crowley, G. M. (2000)
  22. ^ a b BirdLife International (2004)
  23. ^ a b c Baker, G. B., et al. (2007)
  24. ^ Double, M. C. , et al.(2003)
  25. ^ Johnstone, G. W., et al. (1975)
  26. ^ Woods, R. & Gales, R. (2008)

References[edit]

External links[edit]