Seabird Group gathers on Aotea by Amelia Geary
Environmental News Issue 26 Winter 2011

Another species endemic to the Hauraki Gulf outer islands under threat

New Zealand is a hotspot for seabird diversity. Similarly, Great Barrier and its wider islands including the Mokohinau group have the highest diversity of breeding seabirds in the Hauraki Gulf. Despite this, many of New Zealand’s seabirds have never been studied; this may be due to the fact that the petrels (the main kind of seabird in New Zealand) spend most of their time at sea and only come to land to breed. Even then, many of them breed in burrows underground so if you were to sail past a colony you might not even know it was there.

On the 16th of August, a hui took place at Motairehe Marae between seabird researchers, DOC and Ngāti Rehua. Members of the wider Great Barrier community also attended. The researchers came from a range of institutions including Auckland Council, NIWA, Auckland University, DOC National Office and private consultancies. The purpose of the hui was to share the seabird researchers’ knowledge with Ngāti Rehua as much of the work they have been undertaking since 2004 has been conducted on islands either owned by or with close connection to tangata whenua.

Seabird research has most recently been conducted on the Mokohinau Islands, Mahuki Island and the black petrel research on Hirakīmatā/Mt Hobson. Black petrels and gannets have had transmitters attached to them to find out where they go. It turns out that gannets on Mahuki will travel as far as Whangarei for a day’s fishing! The black petrels are a little different. They migrate to South America each year after they have finished breeding. The image shows their eastward and westward migration routes. The darker areas show where the birds spend more time, presumably feeding. Research on the Mokohinau Islands has also involved acoustic research which involves putting out recording devices for extended periods to see which birds live there. This has the added intention of discovering the breeding site of the elusive NZ storm petrel which was thought to be extinct until it was rediscovered in 1987.

Sadly the black petrel research which has been conducted since 1995 has identified that the population is undergoing gradual decline. The main agent of decline is fisheries by-catch, an interaction that is hard to manage from the mainland. With such a long migration, it’s no wonder they are at risk at sea. What this does emphasise however, is the importance of the survival of every chick that hatches on Great Barrier as this is the only viable black petrel population in the world.

Many thanks to Motairehe Marae for hosting the event and providing a delicious lunch, to the Ngāti Rehua Trust Board for supporting the event and to all those that participated and contributed on the day.
Mauri ora.