About Procellaria aequinoctialis Linnaeus, 1758
The white-chinned petrel (Procellaria aequinoctialis Linnaeus, 1758) measures 51–58 cm (20–23 in) in length, with a wingspan of 134–147 cm (53–58 in). Males are heavier, averaging 1,390 g (49 oz), while females weigh around 1,280 g (45 oz). It is not only the largest Procellaria petrel, but also the largest species in its family outside of the giant petrels. This large petrel is sooty-black, with some white marking its throat and chin – more white is present on individuals in the Indian Ocean sector than in the Atlantic. The undersides of its primaries can have a silvery appearance. Its bill may be horn-colored or yellow, with some black marking between the nostrils. It has black legs and feet. In flight, it combines slow wing beats with glides. Although normally quiet, it produces rattling or groaning sounds when at its colony. During the breeding season, the white-chinned petrel breeds on many islands. 2,000,000 pairs breed on South Georgia, between 175,000 and 226,000 pairs breed on the Kerguelen Islands, and 100,000 pairs breed on Disappointment Island. Smaller breeding populations also live on the Crozet Islands, Prince Edward Islands, Campbell Islands, Auckland Islands, Antipodes Islands, and the Falkland Islands. During the non-breeding season, these petrels range from the Antarctic pack ice to the subtropics.
