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Southern royal albatross

The southern royal albatross or toroa, (Diomedea epomophora) is a large seabird from the albatross family. At an average wingspan of above 3 m (9.8 ft), it is one of the two largest species of albatross, together with the wandering albatross. Recent studies indicate that the southern royal albatross may, on average, be somewhat larger than the wandering albatross in mass and have a similar wingspan,[3] although other sources indicate roughly similar size for the two species and the wandering species may have a larger average (and maximum) wingspan in some colonies.[4]

Southern royal albatross
East of Tasmania
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Procellariiformes
Family: Diomedeidae
Genus: Diomedea
Species:
D. epomophora
Binomial name
Diomedea epomophora
Lesson, 1825[2]

Taxonomy

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In flight

Albatrosses belong to family Diomedeidae of the order Procellariiformes, along with shearwaters, fulmars, storm petrels, and diving petrels. They share certain identifying features. First, they have nasal passages that attach to the upper bill called naricorns; the nostrils of the albatross are on the sides of the bill. The bills of Procellariiformes are also unique in that they are split into between seven and nine horny plates. Finally, 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.[5]

This species was once considered conspecific with the northern royal albatross (Diomedea sanfordi) as the royal albatross. The split into two species is widely though not universally accepted: it is recognized by, for example, the IOC World Bird List,[6] BirdLife International,[7] Brooke,[8] and Robertson & Nunn,[9] but not by Clements,[10] while the American Ornithologists' Union has recognized the need for a proposal.[11]

Etymology

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In flight
 
In flight

Diomedea refers to Diomedes, a figure from Greek mythology whose companions turned to birds.[12]

Description

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The southern royal albatross has a length of 112 to 123 cm (44–48 in)[13] and a mean weight of 8.5 kg (19 lb). At Campbell Island, 11 males were found to have a mean mass of 10.3 kg (23 lb) and 7 females were found to have a mean mass of 7.7 kg (17 lb), thus may be heavier on average than most colonies of wandering albatross.[4] Males are about 2 to 3 kg (4.4 to 6.6 lb) heavier than females. Average wingspan has been reported from 2.9 to 3.28 m (9.5 to 10.8 ft), with an upper limit of about 3.50 m (11.5 ft). The wandering albatross can exceed this species in maximum size and averages slightly larger in linear dimensions if not bulk, but the two species are close enough in dimensions that size cannot be used to distinguish between them.[14][15][16] The juvenile has a white head, neck, upper mantle, rump, and underparts. There are black speckles on the mantle, and dark brown or black wings with white flecks on coverts. The tail is white except for the black tip as is the under-wing. Young birds soon lose the black on their tail and backs. White appears on the upperwing gradually, as speckles starting from the leading edge. All ages have a pink bill with black on the cutting edge on the upper mandible, and the legs are flesh-coloured. Young birds with all-dark upperwings can be hard to differentiate from the northern royal albatross. There are clear but subtle differences from the wandering albatross, with the southern royal having a clean black and white appearance, lacking the peach neck spot often found on the wandering albatross. Most wandering albatrosses have dark feathers in the tail and crown and the white in this species expands from the middle of the wing, in larger blotches. The bill is also slightly paler, as well as the dark cutting edge along the middle. The average lifespan is 58 years.[17]

Range

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Breeding Population and Trends[13]
Location Population Date Trend
Campbell Islands 8,200-8,600 pair 1997 Stable
Enderby Island 69 pair 2001 Stable
Auckland Island & Adams Island 20 pair 2001 Stable
Total 28,000-29,500 1997 Stable

Most of the royal albatross population is found between 30° S and 45° S.[18] They range along the southern oceans concentrating on the west and east coast of southern South America, and also in the waters surrounding New Zealand.[13] The majority of the world's population of southern royal albatrosses nest on the rat-free[19] subantarctic Campbell Island, around 8,200 to 8,600 pairs. There are smaller colonies on Adams Island and Auckland Island in the Auckland Islands, 20 pairs combined, and 69 pairs on Enderby Island. Direct counts on Enderby Island using a helicopter and also on foot in January 2017 estimated there were 47 breeding pairs there.[20] There are some sanfordi × epomophora hybrids at the northern royal albatross colony on the Otago Peninsula in New Zealand.

Behaviour

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They attract their mates using methods such as bill-snapping, clapping and gulping. Others ways also include sky-calling with outstretched wings, and neck and head stretched upwards.[21]

Feeding

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The southern royal albatross eats squid and fish, with smaller amounts of carrion, crustaceans, and salps.[13] Its foraging activities normally take place within a 1250 km radius of the breeding site.[22] Although they travel vast distances, royal albatrosses in general tend to forage in somewhat shallower waters and closer to continental shelves than wandering albatrosses.[23]

Breeding

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They prefer to nest on tussock grassland, plateaus, or ridges, and will lay one egg biennially. This will normally take place in November or December. Both parents will incubate the egg, and rear the young. After they are born it takes about 240 days for a baby to grow its wings fully and fly by itself. There is very low mortality rates of the laid eggs once the parents settle in.[24] When feeding the young they will range south to the Campbell Plateau and north to the Chatham Rise.[13]

Conservation

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The IUCN classifies this bird as vulnerable,[1] with an occurrence range of 63,400,000 km2 (24,500,000 sq mi) and a breeding range of 750 km2 (290 sq mi), with a total estimated population of between 28,000 and 29,500 (1997). As a top-tier organism in its natural habitat, it has very few predators but major fishing industries are a huge problem for all albatross species among other seabirds.[25]

The population is recovering from its severe downward spiral in the late 19th and early 20th centuries. By the 1880s, this albatross was extirpated from Auckland Island and Enderby Island. Pigs and cats are still a problem, as they take chicks and eggs, on Auckland Island. Longline fishing is a major problem and a possible emerging threat is Dracophyllum, a shrub that is taking away from their nesting range.[13]

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    Adult with chick on mound nest on Campbell Island
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    Southern Ocean, New Zealand
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    Southern Ocean, New Zealand
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    Pair on Campbell Island
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    Off Kaikōura, New Zealand

Footnotes

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  1. ^ a b BirdLife International (2018). "Diomedea epomophora". IUCN Red List of Threatened Species. 2018: e.T22698314A132641187. doi:10.2305/IUCN.UK.2018-2.RLTS.T22698314A132641187.en. Retrieved 12 November 2021.
  2. ^ Checklist of the birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica (4th ed.). Wellington, N.Z.: Te Papa Press in association with the Ornithological Society of New Zealand. 2010. p. 67. ISBN 978-1-877385-59-9.
  3. ^ Albatross, their world, their ways. De Roy, Jones and Fitter, 2008. Firefly Press
  4. ^ a b CRC Handbook of Avian Body Masses, 2nd Edition by John B. Dunning Jr. (Editor). CRC Press (2008), ISBN 978-1-4200-6444-5.
  5. ^ Double, M. C. (2003)
  6. ^ Gill, F.; Donsker, D.; Rasmussen, P. (Eds.). "Master Lists – IOC World Bird List". IOC World Bird List. Retrieved 26 December 2022.
  7. ^ Lee, James (2008)
  8. ^ Brooke, R. (2004)
  9. ^ Robertson, C. J. R. & Nunn, G. B. (1998)
  10. ^ Clements, J. (2007)
  11. ^ Remsen Jr., C. J. (2008)
  12. ^ Gotch, A. F. (1995)
  13. ^ a b c d e f BirdLife International (2008)
  14. ^ Brooke, Michael, Albatrosses and Petrels across the World. Oxford University Press (2004), ISBN 978-0-19-850125-1
  15. ^ Wood, Gerald (1983). The Guinness Book of Animal Facts and Feats. Guinness Superlatives. ISBN 978-0-85112-235-9.
  16. ^ Harrison, Peter, Seabirds: An Identification Guide. Houghton Mifflin Harcourt (1991), ISBN 978-0-395-60291-1
  17. ^ LaGosh, J. (2004). Diomedea epomophora. Retrieved from http://animaldiversity.ummz.umich.edu/site/accounts/information/Diomedea_epomophora.html
  18. ^ Robertson, C. J. R., & Kinsky, F. C. (1972). The dispersal movements of the royal albatross (Diomedea epomophora). Notornis, 19(4), 289-301.
  19. ^ "Campbell Island conservation sanctuary rat free". The Beehive. Retrieved 2022-05-18.
  20. ^ Baker, G. Barry; Elliott, Graeme; French, Rebecca K.; Jensz, Katrina; Muller, Christopher G.; Walker, Kath (2020). "Development of aerial monitoring techniques to estimate population size of great albatrosses (Diomedea spp.)". Notornis. 67 (1): 321–331.
  21. ^ Moore, Peter (2008)
  22. ^ Waugh, S., Troup, C., Filippi, D., & Weimerskirch, H. (2002). Foraging zones of Southern Royal albatrosses. The Condor, 104(3), 662-667.
  23. ^ Imber (1999). Diet and Feeding Ecology of the Royal Albatross Diomedea epomophora - King of the Shelf Break and Inner Slope. Emu 99(3) 200 - 211
  24. ^ Dilks, P. J., & Wilson, P. R. (1979). Feral sheep and cattle and royal albatrosses on Campbell Island; population trends and habitat changes. New Zealand Journal of Zoology, 6(1), 127-139.
  25. ^ Sullivan, B. J., Reid, T. A., & Bugoni, L. (2006). Seabird mortality on factory trawlers in the Falkland Islands and beyond. Biological Conservation, 131(4), 495–504.

References

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