The Southern giant petrel is a large seabird of the southern oceans. There are two different morphs of this species. The dark morph in which the upper breast, head, and neck are light with the remainder of the plumage being mottled brown. The light morph is rarer and very distinct with only slight black speckles on an otherwise all-white look. As juveniles, the dark morph starts off more sooty brown and pales as it ages. Giant petrels have strong legs and can move around on land effectively. When in flight this species has a somewhat hunchbacked appearance.
Southern giant petrels range from Antarctica to the subtropics of Chile, Africa, and Australia. They breed on numerous islands throughout the southern oceans. The islands with larger populations include the Falkland Islands, South Georgia, South Orkney Islands, Staten Island, South Shetland, Heard Island, Macquarie Island, the Prince Edward Islands, and the Crozet Islands. These birds can be found in areas of pack ice, open ocean, coastal areas, grassy or bare ground, and offshore rocks.
Outside of the breeding season, Southern giant petrels prefer to stay alone; however, around good feeding areas, they may gather in groups and fish together. These birds feed during the day in coastal and pelagic waters where they often follow fishing boats and cruise ships. They are extremely aggressive predators and will kill other seabirds (usually penguin chicks, sick or injured adult penguins, and the chicks of other seabirds). They have even been seen preying on the adult Australasian gannet by holding it underwater and drowning it. Southern giant petrels have also been observed drowning Yellow-nosed and Black-browed albatrosses.
Southern giant petrels are monogamous and form long-lasting pair bonds. Their breeding season begins in October. These birds usually breed in loose colonies except in the Falkland Islands where the colonies are much larger. The nest is a mound of moss, grass, and stones with a depression in the center and is located on the bare or grassy ground. Females lay one white egg that is incubated for 55-66 days. During this time the egg is always guarded by at least one of the parents. When the white chick is born it is brooded for 2 to 3 weeks and it fledges at 104-132 days. Young Southern giant petrels achieve reproductive maturity at 6 or 7 years of age; however, the average age of first breeding is usually 10 years.
Major threats to this species start with the accidental deaths caused by longline fishing as well as trawl fishing near the Falkland Islands. Between 2,000 and 4,000 birds were killed in 1997-1998 due to illegal longline fishing. Also, the number of Southern elephant seals, which is an important source of food as carrion, has been shrinking. Human disturbances and persecution have also adversely affected populations of the Southern giant petrel.
According to the IUCN Red List, the total Southern giant petrel population size is around 95,000-108,000 mature individuals. This includes 19,500 pairs on the Falkland Islands (Islas Malvinas); 5,500 pairs on South Georgia (Georgias del Sur); 5,400 pairs on the South Shetland Islands (Shetland del Sur); 3,350 pairs on South Orkney Island (Orcadas del Sur); 2,500 pairs on Heard and MacDonald Islands; 2,145 pairs on Macquarie Island; 2,300 pairs in Argentina; 230 pairs on the Tristan da Cunha Islands; 280 pairs on the Antarctic Continent; 1,190 pairs on the Antarctic Peninsula; 1,550 pairs on the South Sandwich Islands; 2,800 pairs on the Prince Edward Islands; 1,060 pairs on Iles Crozet and four pairs in Iles Kerguelen. Overall, currently, Southern giant petrels are classified as Least Concern (LC) on the IUCN Red List and their numbers today are increasing.