Data Zone
Justification of Red List category
Overall past and predicted future declines amount to a rapid population reduction over a period of three generations, qualifying the species as Vulnerable. At South Georgia, this species is undergoing a rapid decline over three generations (70 years). On the Crozet and Kerguelen Islands, the populations rapidly declined between 1970-1986, then stabilised, but have recently declined again. Longline fishing is likely to be the main cause of decline in this species, causing reductions in adult survival and juvenile recruitment, and this threat is on-going.
Population justification
In 1998, the total annual breeding population was estimated at 8,500 pairs, equivalent to c. 28,000 mature individuals (Gales 1998). However, current estimates are 1,553 pairs on South Georgia (Georgias del Sur) (Poncet et al. 2006), 1,800 pairs on Prince Edward Island (2008, Ryan et al. 2009), c. 1,900 pairs on Marion Island (2013, ACAP 2009), c. 340 pairs on Iles Crozet (CNRS Chinzè Monitoring Database 2010), c. 354 pairs in Iles Kerguelen (CNRS Chinzè Monitoring Database 2011), and 4 pairs on Macquarie Island (DPIWPE 2010, unpublished data), making a total of c. 6,000 annual breeding pairs. Using the same ratio as Gales (1998) for estimating the number of mature individuals, this would equate to approximately 20,100 mature individuals.
Trend justification
At South Georgia, this species has declined by 1.8% per annum over the past 20 years, and there has been an acceleration in the rate of decrease to over 4% per annum since 1997 (Poncet et al. 2006). Overall, the South Georgian population has declined by 30% between 1984-2004 (Poncet et al. 2006), and by 18% between 2004 and 2015 (A. Wolfaardt in litt. 2016). On Bird Island, adult and post-fledging survival has decreased since the mid 1980s (British Antarctic Survey, unpublished data). On the Crozet Islands, the population stabilised following rapid declines during 1970-1986, but is now declining again (Weimerskirch et al. 1997, Delord et al. 2008). Low juvenile recruitment is believed to be delaying recovery (Weimerskirch et al. 2006). On the Prince Edward Islands, the population is now stable (Nel et al. 2002b, 2002c, Crawford et al. 2003, Ryan et al. 2003, 2009). Overall declines are estimated to exceed 30% over 70 years. However, the long generation time of this species makes it difficult to determine the most appropriate trend period for predicting population trends into the future.
Diomedea exulans breeds on South Georgia (Georgias del Sur) (c. 18% of the global breeding population), Prince Edward Islands (South Africa) (c. 44% of the global population), Crozet Islands and Kerguelen Islands (French Southern Territories) (approximately 38% of the global population) and Macquarie Island (Australia) (approximately four pairs breeding per year), with a total global population of c. 8,050 pairs breeding in any given year (ACAP 2009). At South Georgia, the population declined by 1.8% per annum between 1984 and 2004 (Poncet et al. 2006), and continued to decline by 1.8% per annum between 2004 and 2015 (A. Wolfaardt in litt. 2016). The population on Crozet declined by 54% between 1970 and 1986. From the mid-1980s to late 1990s, the Crozet, Kerguelen and Prince Edward Islands populations appeared to be stable or increasing (Weimerskirch et al. 1997, Weimerskirch and Jouventin 1998, Crawford et al. 2003, Ryan et al. 2003), but declines were later detected (H. Weimerskirch in litt. 2008, Ryan et al. 2009). Overall declines are estimated to exceed 30% over 70 years. Recovery is believed to be impeded by a decline in recruitment rate (Weimerskirch et al. 2006). Non-breeding and juvenile birds remain north of 50°S between subantarctic and subtropical waters with a significant proportion crossing the Indian Ocean to wintering grounds around the southern and eastern coast of Australia (Weimerskirch et al. 2014). A significant proportion of the Crozet and Kerguelen populations disperse into the Pacific and the western coast of South America (Weimerskirch et al. 2014, 2015).
Behaviour Diomedea exulans is a biennial breeding species, although about 30% of successful and 35% of failed breeders (on average) defer breeding beyond the expected year. Adults return to colonies in November, and eggs are laid over a period of 5 weeks during December and January. Most chicks hatch in March and fledge in December. Birds usually return to colonies when 5-7 years old, though they can return when as young as 3 years old. Birds can start breeding as young as 7 or 8 years old, but more typically at 10-12 years old (Tickell 2000). Wandering Albatross typically forages in oceanic waters, however considerable time is spent over shelf areas during certain stages of the breeding season (BirdLife International 2004). Satellite tracking has revealed that juvenile birds tend to forage further north than adults (Weimerskirch et al. 2006, British Antarctic Survey, unpubl. data), bringing them into greater overlap with longline tuna fleets which may be driving falls in recruitment rates (Weimerskirch et al. 1997). Females may also be at greater risk of being caught in tuna fisheries since they tend to forage further north than males (Nel et al. 2002, Weimerskirch et al. 2003, Pinaud and Weimerskirch 2007, Jiménez et al. 2016). It is mostly a diurnal breeder, taking most prey by surface-seizing (ACAP 2009).
Habitat Breeding Wandering Albatross nests in open or patchy vegetation near exposed ridges or hillocks (Carboneras 1992).
Diet Adults feed at sea mainly on cephalopods and fish, often following ships and feeding on offal and galley refuse (Carboneras 1992, Cherel and Klages 1998). Patagonian Toothfish Dissostichus eleginoides is the primary fish species in the diet, potentially obtained as discarded offal (Xavier et al. 2004).
Foraging range This wide-ranging species has a circumpolar distribution, and both breeding and non-breeding birds have very large foraging ranges. Satellite tracking data indicate that breeding birds forage at very long distances from colonies (up to 4,000 km) and that foraging strategies change throughout the breeding season (Froy et al. 2015). A fledgling covered 6,590 km in 28 days after leaving the colony on Marion Island (Clokie 2007).
The observed decline of this species has been shown to be driven largely by incidental catch in fisheries, which has reduced adult survival and juvenile recruitment (Rolland et al. 2010, Pardo et al. 2017). Fisheries were responsible for a 54% decrease in numbers on the Crozet Islands between 1970 and 1986 (Weimerskirch et al. 1997). The South Georgia population is declining rapidly, but other populations (Prince Edward Islands and Crozet Islands) have shown signs of recovery. The South Georgia population disperses throughout the Southern Ocean during the nonbreeding season, although may be most at risk from longline fisheries operating in the south-west Atlantic throughout the year (Jiménez et al. 2014, 2016, Tancell et al. 2016), whereas the Crozet and Prince Edward Island populations are most vulnerable to pelagic longline fishing in the Indian Ocean and Australian region (Weimerskirch 1998, Nel et al. 2002c). The apparent recovery of populations from the Crozet and Prince Edward Islands during the early 1990s was ascribed to reduced fishing effort and relocation of fisheries away from foraging grounds, however increased effort in the late 1990s at various different localities may once again be impacting these populations (Weimerskirch et al. 1997, Nel et al. 2002b), as even low bycatch rates will affect the species due to the small population size (ACAP 2009). The Macquarie population was harvested extensively by sealers and despite recoveries in the early 20th century, it experienced subsequent declines that were also attributed to longline fisheries (de la Mare and Kerry 1994). Additionally, chicks are vulnerable to the accumulation of anthropogenic debris and fishing hooks, which may kill a small number annually (Nel and Nel 1999, Phillips et al. 2010, 2016).
The impacts of predation by introduced species are severe for some breeding populations. On Kerguelen, in some years, certain colonies have suffered complete breeding failure due to chick predation by cats Felis catus (H. Weimerskirch in litt. 2008). House mice Mus musculus have been recorded attacking Wandering Albatross chicks on Marion Island since 2003 and continue to affect up to 1% of the population (Dilley et al. 2015). There has been extensive habitat loss and degradation at South Georgia (Islas Georgias del Sur) due to the activities of Antarctic Fur Seals Arctocephalus gazelle (ACAP 2009).
Shifts in the oceanic habitat have been demonstrated to negatively impact the species, and are likely to be exacerbated with future climate change, and expected to cause significant declines over the next three generation period (Pardo et al. 2017). Several climatic variables have a significant correlation with mortality and breeding success, sometimes with different effects among different locations and on juvenile vs. adult survival (Pardo et al. 2017).
Conservation Actions Underway
CMS Appendix II and ACAP Annex 1. Population monitoring and foraging studies are being undertaken at South Georgia (Georgias del Sur), the Prince Edward Islands, Crozet, Kerguelen and Macquarie. The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has introduced measures which have reduced bycatch of albatrosses around South Georgia by over 99%. Recently, other Regional Fisheries Management Organisations, including the tuna commissions, have taken initial steps to reduce seabird bycatch rates. The Prince Edward Islands are a special nature reserve and Macquarie is a World Heritage Site. Large parts of the breeding colonies on the Crozet and Kerguelen Islands are now part of a Nature Reserve. On Macquarie, cats have been eradicated (Quin 2008), and the island was declared to be rabbit, rat and mouse-free in 2014 following a large eradication project which commenced in 2014 (Springer 2016).
115 cm. Huge albatross with variable plumage, whitening with age. Juvenile chocolate-brown with white face mask, white underwing with black tip and trailing margin. Underparts become pure white. On upperparts, back whitens first, followed by crown and rump, white wedge forms in centre upperwing, extending to coverts. Black tips remain on outer tail feathers. Pink bill and flesh legs. Similar spp. Enlargement of white upperwing area is species-specific: D. exulans central wedge, Southern Royal Albatross D. epomophora from forewing, Northern Royal Albatross D. sanfordi only in scapular area. Probably indistinguishable from recently split Tristan D. dabbenena and Antipodean D. antipodensis albatrosses at-sea.
Text account compilers
Stattersfield, A., Stuart, A., Sullivan, B., Symes, A., Fjagesund, T., Hermes, C., Calvert, R., Anderson, O., Martin, R., Moreno, R., Nel, D., Small, C.
Contributors
Crawford, R., Weimerskirsch, H., Cooper, J., Ryan, P.G., Croxall, J., Wolfaardt, A., Gales, R., Phillips, R.
Recommended citation
BirdLife International (2024) Species factsheet: Snowy Albatross Diomedea exulans. Downloaded from
https://datazone.birdlife.org/species/factsheet/snowy-albatross-diomedea-exulans on 22/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 22/12/2024.