does the original bird have a unique call?
A  harsh "arrah-arrah" or "urrah-urrah".
Australasian gannet
Its typical call is a harsh "arrah-arrah" or "urrah-urrah", which is emitted upon approaching or arriving at the colony or as a threat. 
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.
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Australasian gannet [SEP] Call
The Australasian gannet is generally silent at sea and loud and vocal at the colony in the day and at times overnight during the breeding season. Its typical call is a harsh "arrah-arrah" or "urrah-urrah", which is emitted upon approaching or arriving at the colony or as a threat. The calls can vary between individuals, and the female's call is lower pitched than the male's.