Justification of Red List Category
Recent analysis of trend data for the global population over the past three generations (64 years) gives a best case estimate of a 17 % increase and a worst case scenario of a 7.2 % decline (Chown et al. unpubl. report 2008); declines consequently do not approach the threshold for classification as Vulnerable and the species is listed as Least Concern.
Chown et al. (unpubl. report 2008) estimates a population size of 54,000 pairs, whereas a total of c.47,800 pairs (roughly equating to 150,000 total individuals) can be estimated from Patterson et al. (2008) and unpublished data from Falklands Conservation and British Antarctic Survey. This consists of an estimated 19,500 pairs on the Falkland Islands (Islas Malvinas), 5,500 pairs on South Georgia (Georgias del Sur), 5,400 pairs on South Shetland Islands (Shetland del Sur), 3,350 pairs on South Orkney Island (Orcadas del Sur) (British Antarctic Survey unpubl. data), 2,500 pairs on Heard and MacDonald Islands (DPIW unpubl. data), 2,145 pairs on Macquarie Island, 2,300 pairs in Argentina (Quintana et al. 2006), 230 pairs on the Tristan da Cunha Islands, 280 pairs on the Antarctic Continent. In addition, Patterson et al. (2008) estimate 1,190 pairs on the Antarctic Peninsula, 1,550 pairs on the South Sandwich Islands, 2,800 pairs on Prince Edward Islands (Ryan et al. 2009), 1,060 pairs on Iles Crozet and four pairs in Iles Kerguelen.
Recent trends are variable, with some populations continuing to decline (British Antarctic Survey unpubl. data, Patterson et al. undated), some stable (Gonzalez-Solis and Croxall 2005, Ryan et al. 2009, Cuthbert et al. 2014) and others showing substantial increases, including populations on Patagonia, Argentina (Quintana et al. 2006), the Falkland Islands (Islas Malvinas) (Reid and Huin 2005) and South Georgia (Poncet et al. in litt. 2008). Importantly, the latter populations represent the two largest populations in the world; thus, the overall global trend is now increasing. Combining trend data for both regions (north and south of 60°S) gives a best estimate of a 17 % increase and a worst case scenario of a 7.2 % decline over the past three generations (64 years) (Chown et al. unpubl. report 2008 ), and it is precautionarily assumed here to have undergone a slow decline during this period.
Macronectes giganteus breeds on the Falkland Islands (Islas Malvinas), Staten Island and islands off Chubut Province (Argentina), South Georgia (Georgias del Sur), the South Orkney (Orcadas del Sur) and South Shetland Islands (Shetland del Sur), islands near the Antarctic Continent and Peninsula, Prince Edward Islands (South Africa), Crozet Islands (French Southern Territories), Heard Island and Macquarie Island (Australia), with smaller populations on Gough Island, Tristan da Cunha (St Helena to UK), Diego Ramirez and Isla Noir (Chile), Kerguelen Islands (French Southern Territories), and four localities on the Antarctic Continent including Terre Adélie. In the 1980s, the population was estimated at 38,000 pairs (Hunter 1985), declining by 18% to 31,000 pairs in the late 1990s (Rootes 1988). Populations at Heard and Macquarie declined 50% between the 1960s and late 1980s (Woehler 1991, 2006). Many Antarctic Peninsula populations decreased to the mid-1980s (e.g. >50% at Signy, South Orkneys) (Patterson et al. undated). The population at Terre Adélie declined from c.80 pairs in the 1960s to 10-15 pairs in 2000. However, recent data indicate a number of populations have stabilised or increased, e.g. Prince Edward Islands (Ryan et al. 2009), Possession Island (Crozet) (Patterson et al. undated), Gough Island (Cuthbert et al. 2014, RSPB and UCT unpubl. data), Heard Island (Woehler 2006), and Isla Arce and Gran Robredo (Chubut, Argentina) (Quintana et al. 2006). A comprehensive 2004-2005 survey of all breeding colonies on the Falkland Islands (Islas Malvinas) recorded 19,523 breeding pairs (Reid and Huin 2005). This represents an increase over the previous estimate of 5,000-10,000 pairs in the Falkland Islands (Islas Malvinas), and is thought to represent a combination of improved knowledge and a genuine population increase. Similarly, a comprehensive survey of all known breeding sites in the South Georgia archipelago, between 2005 and 2006, indicates a population increase since the 1980s (Poncet et al. in litt. 2008), and the global population is now estimated at c.54,000 breeding pairs (Chown et al. unpubl. report 2008). Data from birds tracked from South Georgia indicate that breeders remain in the same ocean sector during the non-breeding season (Hunter and Brooke 1982) which is also the case for birds tracked from islands off Chubut Province (Argentina) (Blanco and Quintana 2014). By comparison, ringing recoveries and satellite tracking of individuals suggest that juveniles disperse much more widely (Hunter 1984b, Copello et al. 2009, Blanco and Quintana 2014, Thiers et al. 2014). Males and females have distinct foraging ranges during the breeding season (Gonzalez-Solis and Croxall 2005, Quintana et al. 2010).
It typically nests in loose colonies on grassy or bare ground. However, in the Falkland Islands (Islas Malvinas) it can nest in large, relatively dense colonies (Reid and Huin 2005). Average age of first breeding is c.7 years, and mean adult annual survival at South Georgia is 90% (Hunter 1984a). It feeds on carrion, cephalopods, krill, offal, discarded fish and refuse from ships, often feeding near trawlers and longliners (Hunter and Brooke 1982, Hunter 1983). Males and females exhibit clearly defined spatial segregation in their foraging ranges (Gonzalez-Solis et al. 2000, BirdLife International 2004, Quintana et al. 2010).
A total of 2,000-4,000 giant-petrels were estimated killed in illegal or unregulated Southern Ocean longline fisheries for Patagonian Toothfish Dissostichus eleginoides in 1997-1998 (CCAMLR 1997, 1998) and the species has been shown to be killed in trawl fisheries in the Falkland Islands (Islas Malvinas) (Sullivan et al. 2006). However, improved mitigation in many legal fisheries means their bycatch has been virtually eliminated and there is no indication that rates of bycatch are causing significant declines at a global level. Volcanoes have the potential to cause some declines and displacement on McDonald Islands, but this is likely to have a negligible effect on the population.
Conservation Actions Underway
CMS Appendix II and ACAP Annex 1. It is monitored at South Georgia, Marion, Crozet and Macquarie Islands, and at Terre Adélie. Several breeding islands are nature reserves; Gough and Macquarie are World Heritage Sites. The population at Gough Island has been counted annually since 2003, and a monitoring protocol for breeding success and adult survival is in place (Cuthbert et al. 2014).
87 cm. Very large petrel with huge bill. White morph unmistakable, normally flecked black. Dark morph has sooty-black juvenile, becoming paler with age. Adult has off-white head, neck, upper breast. Rest of plumage mottled greyish-brown, with paler feather along leading edge of wing. Pale bases to underside of inner primaries. All ages, pale pea-green tip to yellowish bill. Can appear uniform at sea. Grey-brown legs. Similar spp. Same size as smaller albatrosses, but has huge bill, shorter narrower wings and humpbacked shape. Adult Northern Giant-petrel M. halli has red-brown tip to bill, and lacks pale leading edge to wing.
Text account compilers
Stattersfield, A., Stuart, A., Sullivan, B., Black, A., Symes, A., Wheatley, H., Bird, J., Fjagesund, T., Butchart, S., Hermes, C., Martin, R., Moreno, R., Shutes, S.
Bretagnolle, V., Phillips, R., Bond, A., Fraser, W., Blanco, G., Quintana, F., Cooper, J., Pistorius, P., Croxall, J., Ryan, P.G., Patterson-Fraser, D., Keys, H., Deliry, C., Hilton, G.
BirdLife International (2021) Species factsheet: Macronectes giganteus. Downloaded from http://www.birdlife.org on 23/01/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/01/2021.