Australian Gannet
Encyclopedia
The Australasian Gannet (Morus serrator or Sula bassana, also Australian Gannet, Tākapu) is a large seabird
of the gannet
family Sulidae.
Adults are mostly white, with black flight feathers at the wingtips and lining the trailing edge of the wing. The central tail feathers are also black. The head is yellow, with a pale blue-grey bill edged in black, and blue-rimmed eyes.
Young birds have mottled plumage in their first year, dark above and light below. The head is an intermediate mottled grey, with a dark bill. The birds gradually acquire more white in subsequent seasons until they reach maturity after five years.
Their breeding habitat is on islands off Victoria
, Tasmania
and New Zealand
. They normally nest in large colonies on coastal islands. A large exception is the protected colony on the mainland at Cape Kidnappers
(5000 pairs). There are also mainland colonies at Muriwai
and Farewell Spit
.
Gannet pairs may remain together over several seasons. They perform elaborate greeting rituals at the nest, stretching their bills and necks skywards and gently tapping bills together. The adults mainly stay close to colonies, whilst the younger birds disperse.
These birds are plunge divers
and spectacular fishers, plunging into the ocean at high speed. They mainly eat squid
and forage fish
which school
near the surface.
Numbers of Australasian Gannet have been increasing since 1950, although some colonies have disappeared and others have decreased in size.
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
of the gannet
Gannet
Gannets are seabirds comprising the genus Morus, in the family Sulidae, closely related to the boobies.The gannets are large black and white birds with yellow heads. They have long pointed wings and long bills. Northern gannets are the largest seabirds in the North Atlantic, with a wingspan of up...
family Sulidae.
Adults are mostly white, with black flight feathers at the wingtips and lining the trailing edge of the wing. The central tail feathers are also black. The head is yellow, with a pale blue-grey bill edged in black, and blue-rimmed eyes.
Young birds have mottled plumage in their first year, dark above and light below. The head is an intermediate mottled grey, with a dark bill. The birds gradually acquire more white in subsequent seasons until they reach maturity after five years.
Their breeding habitat is on islands off Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
, Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
and New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. They normally nest in large colonies on coastal islands. A large exception is the protected colony on the mainland at Cape Kidnappers
Cape Kidnappers
Cape Kidnappers is a headland at the southeastern extremity of Hawke Bay on the east coast of New Zealand's North Island. It is located 20 kilometres southeast of the city of Napier...
(5000 pairs). There are also mainland colonies at Muriwai
Muriwai
Muriwai, also called Muriwai Beach, is a coastal community located on the west coast of North Island, New Zealand. It is also home to a large colony of gannets.- Location :...
and Farewell Spit
Farewell Spit
Farewell Spit is a narrow sand spit situated at , at the northern end of the South Island of New Zealand. Known to the Māori as Tuhuroa, it runs eastwards from Cape Farewell, the island's northernmost point...
.
Gannet pairs may remain together over several seasons. They perform elaborate greeting rituals at the nest, stretching their bills and necks skywards and gently tapping bills together. The adults mainly stay close to colonies, whilst the younger birds disperse.
These birds are plunge divers
Diving bird
Diving birds are birds which plunge into water to catchfish or other food. They may enter the water from flight, as does the brown pelican , or they may dive from the surface of the water...
and spectacular fishers, plunging into the ocean at high speed. They mainly eat squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
and forage fish
Forage fish
Forage fish, also called prey fish or bait fish, are small fish which are preyed on by larger predators for food. Predators include other larger fish, seabirds and marine mammals. Typical ocean forage fish feed near the base of the food chain on plankton, often by filter feeding...
which school
Shoaling and schooling
In biology, any group of fish that stay together for social reasons are said to be shoaling , and if, in addition, the group is swimming in the same direction in a coordinated manner, they are said to be schooling . In common usage, the terms are sometimes used rather loosely...
near the surface.
Numbers of Australasian Gannet have been increasing since 1950, although some colonies have disappeared and others have decreased in size.