how does the first one mate?
It sexual maturity at six or seven years of age and the breeding season begins in October.
Southern giant petrel
The southern giant petrel achieves sexual maturity at six or seven years of age; however the average age of first breeding is ten years. Its breeding season begins in October. 
what is a australasian gannet? A large seabird. where is it found? Steep Point in Western Australia, along the southern and eastern Australian coastline to the vicinity of Rockhampton in Queensland, as well as the North and South Islands of New Zealand, Lord Howe and Norfolk Islands. what does it eat? Forage fish and cephalopods. apart from this bird what are the other predators of the first one? Other fishes like tuna, striped bass, cod, salmon, barracuda and swordfish, as well as sharks, whales, dolphins, porpoises, seals, sea lions, and seabirds. where are they found? They are found along coastlines and also in lakes and rivers. does the original bird have a unique call? A  harsh "arrah-arrah" or "urrah-urrah". who are its predators? Southern giant petrel , kelp gull, and Pacific gull.
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Southern giant petrel [SEP] Reproduction
The southern giant petrel achieves sexual maturity at six or seven years of age; however the average age of first breeding is ten years. Its breeding season begins in October. Its nest is a mound of moss, grass, and stones with a depression in the centre and is located on bare or grassy ground. They form loose colonies except in the Falkland Islands where the colonies are much larger. One immaculate white egg that is is laid. It is incubated for 55–66 days, where it is always guarded by at least one of the parents. When the white chick is born it is brooded for two to three weeks and it fledges at 104–132 days.