There’s a new attraction at Tāwharanui: a fake gannet colony has been established with the aim of attracting the real thing. A team of enthusiastic volunteers set up the new ‘colony’ of sixteen plastic decoys together with nest mounds and a sound system playing gannet calls.The hope is that some passing young gannets will be encouraged by both the sight and sound of our colony and decide to adopt it as their own. While that might sound fanciful, the technique has already proved successful at Young Nicks Head near Gisborne and at Motuora Island near Kawau.
Gannets generally return to their birthplace to breed. So to get them to set up somewhere new requires a bit of effort. The pest-free status of Tāwharanui provides a perfect location for them to establish a new colony. Apart from Muriwai, the other five gannet colonies in the Auckland region are all on offshore islands.
The Australasian Gannet is a very large bird - up to 90cm long and with a wingspan of 1.8 meters. They are found in New Zealand and south-eastern Australia with an estimated breeding population of 55,000 pairs. 87% of the adult population is in New Zealand with large colonies at the Three Kings, White Island, Gannet Island at Kawhia and Cape Kidnappers.
About this time of year gannets return to their colonies to breed. A single egg is laid from August onwards with the chicks hatching in late spring to early summer. Fledglings from New Zealand fly directly to Australia and return from their OE in their third year, although they won’t start breeding until they are five to seven years old.
Australasian Gannets are not a threatened species but TOSSI is keen for them to breed at the Tāwharanui Open Sanctuary. This is not just about returning another ‘missing’ species to the sanctuary: gannets play an important role in coastal ecosystems by bringing nutrients from the sea to the land, enriching the soil and providing food for invertebrates.
The presence of this iconic and spectacular bird at Tāwharanui alongside our Marine Reserve may also encourage people to consider the relationship between the terrestrial and marine ecosystems and also New Zealand’s crucial role in seabird conservation.
Surrounded by productive oceans, New Zealand is a World Hotspot for seabirds. More than a third of the world’s seabird species (140) occur in our territory and thirty-six of these species are NZ endemics – breeding nowhere else.
Auckland’s Hauraki Gulf is one of the most important places in NZ for seabirds. At any one time there is literally millions of seabirds out in the gulf. However, few people get to appreciate this richness as most of these birds breed on the outer islands like Little Barrier, Mokohinau Islands and the Poor Knights where they are safe from introduced pests such as cats, rats and stoats.
The project has been funded through the Environmental Initiatives Fund of Auckland Council and by TOSSI.