The Australasian gannet is a large seabird of about 89cm in length and weighing nearly 2.5 kg. It is mainly white, with a buff yellow head, and black trailing edges to its wings; the central tail feathers are also black. The juvenile is  spotted above (grey/brown) with brownish streaks below. The adult plumage takes about three years to develop.

Gannets feed mainly on small fish and some squid taken from deep waters or harbours and estuaries. They dive vertically from heights of up to 30m, entering the water at tremendous speed. They have inflatable air sacs beneath the skin on the lower neck and breast that act as shock absorbers as they enter the water.

Gannets range widely in NZ seas during winter but return to their breeding sites around June/July. The nests are made within close proximity of other nests, out of seaweed and guano. They usually lay just one egg, incubated for 44 days by both sexes. The chicks fledge at between 13 and 17 weeks old, when they fly across the Tasman Sea to Australian waters. They remain there until they reach breeding age at between three and seven years old (usually five), when they return to their breeding colonies to breed for the first time. There is a lot of chattering in a gannet colony, but away from the breeding site the birds are normally silent. Muriwai, on the west coast near Auckland, is the mainland colony closest to Tiritiri Matangi. Pairs can stay together for several years.

On Tiritiri Matangi gannets can often be seen from the wharf area and from the East Coast Track, diving for food in the waters close to the Island. From 2011, efforts have been made to attract gannets to Motuora Island, north of Tiritiri Matangi. Breeding was first attempted there in 2013. 

Learn more about the Australian gannet at New Zealand Birds Online.

 Photography by: Peter Craw ©(left) and by Dr Kerry Rodgers © (right)

References: Heather, B.D.; Robertson, H.A. 2000 The Field Guide to the Birds of New Zealand. Auckland, Viking.