Hutton's Shearwater

These birds live entirely at sea except when breeding. During the September–March (spring and summer) breeding season, adults migrate to New Zealand waters; there have been individual sightings around the entire New Zealand coast, but most birds are feeding off the eastern South Island, especially between Cook Strait and Banks Peninsula. Large flocks can be seen off the Kaikoura Coast during summer. Outside the breeding season, they are mostly found in Australian waters. Geo-locators fitted on young birds revealed some circumnavigate Australia in an anti-clockwise direction in the 4–5 years leading up to sexual maturity.

The eight breeding colonies discovered in 1964 have been reduced to two, the other lower-altitude colonies destroyed by feral introduced pigs. Their main predators are introduced stoats, which kill about 0.25% of adults and 12% of chicks each year in their nesting burrows. The overall growth rate is still positive, though, so stoats are not considered a major threat. Some parts of the colonies are in steep, unstable sites. The browsing of deer, goats, and pigs in these steep areas has contributed to erosion, which has damaged the Hutton's shearwater burrows and the population. However, control of pigs has led to better vegetation cover at the colonies and lessened destruction of burrows. Although there are an estimated 114,000 breeding pairs, both breeding colonies are vulnerable to predators or erosion, so a new colony (Te Rae o Atiu) was established on the Kaikoura Peninsula in 2005. First, a small transfer of 10 nestlings was sent in April 2005. After that, roughly 100 additional nestlings were moved annually each March in 2006, 2007, 2008, 2012 and 2013. Chicks translocated from the Kowhai colony were hand-fed in artificial burrows to ensure they would imprint on the new colony, and since 2010 have been returning there to breed. A predator-proof fence was built around the 2 hectares (4.9 acres) site in February 2010 by the Hutton's Shearwater Charitable Trust. Fledgling shearwaters are disoriented by bright lights, and problems with crash-landing birds have prompted the Kaikoura District Council to try new streetlighting which can be adjusted during fledging times.