The Southern Giant Petrel occurs in brown and rarer white phases. It breeds on Southern Ocean islands and the Antarctic Continent and is a distinct species from the related Northern Giant Petrel.
Most birds are brown with a yellowish bill tipped green. The rarer white phase is white with scattered black feathers; the Northern Giant Petrel has a reddish bill tip.
At Punta Tombo, Argentina, Southern Giant Petrel attendance at a Magellanic Penguin colony varied by season. Across 1,724 morning and evening surveys from September 1986 to April 2023, counts had four peaks: 0.4 birds per count in late October and 2.2 in mid-December.
Mean counts reached 5.1 in mid-February and 1.8 in early April. On 19 April 2023, researchers watched three petrels attempt to prey on a molting adult penguin. Across the long-term records, 16 attacks or attempts were observed, including six directed at adults.
An extinction-risk assessment has not been added yet.
Mean counts at Punta Tombo were 0.4 in late October, 2.2 in mid-December, 5.1 in mid-February, and 1.8 in early April.