Grey-headed albatross

Mollymawks are a type of albatross that belong to the family Diomedeidae from 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, although the nostrils of an 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.[3] They also have a salt gland situated above the nasal passage that helps desalinate their bodies, to compensate for the ocean water they imbibe. It excretes a concentrated brine from the nostrils.[4]

The name chrysostoma is derived from two Greek words. Khrusos means "gold" and stoma means "the mouth", in reference to its golden bill.[5]

The grey-headed albatross averages 81 cm (32 in) in length and 2.2 m (7.2 ft) in wingspan. Weight can range from 2.8 to 4.4 kg (6.2 to 9.7 lb), with a mean mass of 3.65 kg (8.0 lb).[6] It has a dark ashy-grey head, throat, and upper neck, and its upper wings, mantle, and tail, are almost black. It has a white rump, underparts, and a white crescent behind its eyes. Its bill is black, with bright yellow upper and lower ridges, that shades to pink-orange at the tip. Its underwings are white with a lot of black on the leading edge and less on the trailing edge. Juveniles have a black bill and head and a darker nape. Its eye crescent is indistinct and its underwing is almost completely dark.[7]

Grey-headed albatrosses nest in colonies on several islands in the Southern Ocean, with large colonies on South Georgia in the South Atlantic, and smaller colonies on Islas Diego Ramírez, Kerguelen Islands, Crozet Islands, Marion Island, and Prince Edward Islands in the Indian Ocean, Campbell Island and Macquarie Island south of New Zealand, and Chile. While breeding, they will forage for food within or south of the Antarctic Polar Frontal Zone.[8][9] Birds that roost in the Marion Island area forage for food in the sub-tropical zone.[10] Juveniles or non-breeding adults fly freely throughout all the southern oceans,[7] north to 35°S.[11]

Flying in Drake's Passage, Southern Ocean

The IUCN classifies this bird as endangered due to rapidly declining numbers in South Georgia which holds around half the world's population.[1] It has an occurrence range of 79,000,000 km² (31,000,000 sq mi) and a breeding range of 1,800 km² (690 sq mi),[7] with a population, estimated in 2004, of 250,000.[16][17] Estimates place 48,000 pairs at South Georgia Island,[18] 6,200 on Marion Island,[19] 3,000 pairs on Prince Edward Islands,[20] 7,800 pairs on Campbell Island,[21] 16,408 pairs in Chile,[22] 84 pairs on Macquarie Island, 5,940 on Crozet Island, and 7,905 on Kerguelen Islands[23]

Populations have been shrinking based on different studies. Bird Island numbers have been reduced 20% to 30% in the last 30 years.[24] Marion Island registered 1.75% reduction per year until 1992 and now appears to be stable.[25] Campbell Island has seen reduction of 79% to 87% since the 1940s.[26] Overall, the trends looks like a 30-40% reduction over 90 years (3 generations).[7] Illegal or unregulated fishing in the Indian Ocean for the Patagonian toothfish, Dissostichus eleginoides resulted in 10–20,000 dead albatrosses, mainly this species, in 1997 and 1998.[27][28][29] Longline fishing is responsible for other deaths.[23][30]

To assist this species, studies are being undertaken at most of the islands. Also, Prince Edward Islands is a special nature preserve, and Campbell Island[31] and Macquarie Island[32] are World Heritage Sites.

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• Clay, T.A.; Small, C.; Tuck, G.N.; Pardo, D; Carneiro, A.P.B.; Wood, A.G.; Croxall, J.P.; Crossin, G.T.; Phillips, R.A. (2019). "A comprehensive large‐scale assessment of fisheries bycatch risk to threatened seabird populations". Journal of Applied Ecology. 141 (6): 1117–1129. doi:10.1111/1365-2664.13407.
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• Croxall, J. P.; Gales, R. (1998). "Assessment of the conservation status of albatrosses". In Robertson, G.; Gales, R. (eds.). Albatross biology and conservation. Chipping Norton, Australia: Surrey Beatty & Sons.
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• Croxall, J. P.; Silk, J.R.D.; Phillips, R.A.; Afanasyev, V.; Briggs, D.R. (2005). "Global Circumnavigations: Tracking year-round ranges of nonbreeding Albatrosses". Science. 307 (5707): 249–250. Bibcode:2005Sci...307..249C. doi:10.1126/science.1106042. PMID 15653503. S2CID 28990783.
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• Ehrlich, Paul R.; Dobkin, David, S.; Wheye, Darryl (1988). The Birders Handbook (First ed.). New York, NY: Simon & Schuster. pp. 29–31. ISBN 978-0-671-65989-9.{{cite book}}: CS1 maint: multiple names: authors list (link)
• Gales, R. (1998). "Albatross populations: status and threats". In Robertson, G.; Gales, R. (eds.). Albatross biology and conservation. Chipping Norton, Australia: Surrey Beatty & Sons.
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• Moore, P. J. (2004). "Abundance and population trends of mollymawks on Campbell Island". Science for Conservation. Wellington, NZ: Department of Conservation. 242.
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• Nel, D. C.; Ryan, P. G.; Crawford, R. J. M.; Cooper, J.; Huyser, O. (2002). "Population trends of albatrosses and petrels at sub-Antarctic Marion Island". Polar Biology. 25 (2): 81–89. doi:10.1007/s003000100315. S2CID 11970816.
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• Phillips, R. A.; Silk, J. R. D.; Phalan, B.; Catry, P.; Croxall, J. P. (2004). "Seasonal sexual segregation of two Thalassarche albatross species: competitive exclusion, reproductive role specialization or foraging niche divergence?". Proceedings of the Royal Society B. 271 (1545): 1283–1291. doi:10.1098/rspb.2004.2718. PMC 1691717. PMID 15306353.
• Poncet, S.; Robertson, G.; Phillips, R. A.; Lawton, K.; Phalan, B.; Trathan, P. N.; Croxall, J. P. (2006). "Status and distribution of wandering Black-browed and Grey-headed Albatrosses breeding at South Georgia". Polar Biology. 29 (9): 772–781. doi:10.1007/s00300-006-0114-9. S2CID 21411990.
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• Ryan, P. G.; Cooper, J.; Dyer, B. M.; Underhill, L. G.; Crawford, R. J. M.; Bester, M. N. (2003). "Counts of surface-nesting seabirds breeding at Prince Edward Islands, Summer 2001/02". African Journal of Marine Science. 25: 441–451. doi:10.2989/18142320309504033. S2CID 84355648.
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• Xavier, J. C.; Croxall, J. P.; Trathan, P. N.; Wood, A. G. (2003). "Feeding strategies and diets of breeding grey-headed and wandering albatrosses at South Georgia". Marine Biology. 143 (2): 221–232. doi:10.1007/s00227-003-1049-0. S2CID 85569322.

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• Species factsheet - BirdLife International
• Photos and fact file - ARKive
• Photos - Christopher Taylor Nature Photography