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birds in the west with janie vaughan Seabirds need land too


The Hauraki Gulf is seabird central when it comes to global breeding sites for seabirds but the Waitakere area is less well frequented.


Cook’s petrel,


Pterodroma cookii, titi. Fossils and midden remains confirm that Cook’s Petrel was once very common and their summer breeding range included the North and South Islands but, today, over 90% of the population breeds on Little Barrier Island and the remainder on Codfish Island. Unfortunately weka were introduced to Codfish Island in the past and significantly reduced the Cook’s Petrel population there before being removed. And with the eradication of cats and rats from Little Barrier Island the breeding success rate has increased from about 5% to over 60%. These small seabirds are semi-colonial nesters in the forest. As they come to their nest they crash through the branches and land with a thump before shuffling to their chick’s burrow. The parents alternate turns incubating and feeding the chick and each may be out foraging for up to six days. The parents may be heard calling as they cross Auckland at night returning from foraging in the Tasman Sea. When family duties are over, about April, Cook’s Petrels fly to the American side of the Pacific Ocean. They weigh about 190 grams, and have a wing span of 65cm and as with many other seabirds have a fast flight, soaring, rising and dipping over the ocean, as they feed on small squid, fish and crustaceans.


Australasian gannet, Morus serrator, takapu.  (09) 813 5418


An easily-viewed colony of breeding seabirds is a rarity but one that can be enjoyed in the Waitakeres. More than 1200 pairs of gannets return to Muriwai every July. A pair may mate for life, but divorces do occur. As the young do not leave the colony until about February this provides a long window of opportunity to visit them. Muriwai and the nearby islands have the flat platforms gannets prefer for their nests and also the air currents to give the birds “lift” to commence their flight. The young have brown feathers and will not gain full adult plumage until they are five years old. They will spend at least three of those years in Australian waters, independent of land. These impressive birds’ wingspan is about 1.8 metres and they weigh about 2.3 kg. In 1769 Joseph Banks shot some gannets which were cooked in


“goose pye” for Captain Cook and his crew to enjoy for Christmas dinner rather than being saved as specimens for research. As the words gander and gannet have the same English root the reference to goose is not that surprising. Gannet’s eyes are of special interest to researchers as gannets torpedo dive from up to 30 metres and hit the water with incredible force, yet can still see their prey underwater.


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The Grey-faced petrel, Pterodroma macroptera, oi or titi. Grey-faced petrels, rarely seen within sight of land, are the most common breeding petrel in NZ, and small numbers of them do breed in the rock stacks of the Waitakere coast, and near Huia’s Foster Bay. They are winter breeders and one egg is laid at the end of a long burrow, or amongst vegetation. The young are very susceptible to rat predation, but with the extensive predator control in the Ark in the Park it may be possible to


formally reintroduce them to the mainland in the future. Reintroduction of seabirds is successfully occurring in some areas. Very young chicks may be put in artificial burrows and fed but this must happen before they are imprinted on their birth site. Many seabirds are faithful to their birth site all their life. It is also possible to play


loud recordings of the adult calls to entice young adults to an attractively prepared new area and hope they will stay when they begin to breed, as is happening at Tawharanui. An adult will guard the chick for about three days after it hatches then forage over long distances to return to feed the chick about once every four days. The chick will mature over the next 7 to 8 years and will weigh about 500 grams with a wingspan of one metre. It will be brownish black in colour with a grey face.


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