Hutton's Shearwater

The Hutton's shearwater, known to the Māori as kaikōura tītī, is a medium-sized seabird weighing approximately 350 grams with a wingspan stretching to 75 centimeters. It exhibits a brown plumage with a contrasting white underbelly and a distinctive brown collar. The underwing is bordered darkly, and the bird possesses a dark grey bill and pinkish feet with dark webbing.

Identification Tips

To distinguish Hutton's shearwater from similar species, look for its dark grey "armpits" and the dark borders on the underwing. When observed at a breeding colony, its loud cackling call is a helpful identifier.

Habitat

This seabird is uniquely known to breed in alpine areas, specifically within the Seaward Kaikōura Range in New Zealand.

Distribution

Hutton's shearwaters are pelagic, spending their lives at sea, except during the breeding season from September to March. They are predominantly found in New Zealand waters, with large flocks often seen off the Kaikōura coast during summer. Outside the breeding season, they are mostly observed in Australian waters.

Behaviour

These birds exhibit remarkable diving abilities, plunging up to 20 meters to feed on small fish and krill. They are adept at catching prey underwater, either by plunging from above or by paddling slowly with their heads submerged before diving.

Song & Calls

At breeding colonies, Hutton's shearwaters are known for their loud, cackling calls.

Breeding

Breeding occurs in burrows at altitudes of 1200–1800 meters in the sub-alpine to alpine zones. The species lays a single white egg around November, which is then incubated for approximately 50 days. Chicks take around 80 days to fledge.

Similar Species

The fluttering shearwater is similar in appearance but can be differentiated by the lack of dark grey "armpits" seen in Hutton's shearwater.

Diet and Feeding

Hutton's shearwaters primarily feed on small fish and krill, using their long bills to catch prey underwater.

Conservation status

The conservation status of Hutton's shearwater is Endangered, with only two remaining breeding colonies. Efforts to protect the species include community initiatives to rescue crash-landed birds and the establishment of a protected area with a predator-proof fence and man-made burrows.

Threats to the breeding colonies

Introduced pigs have destroyed six of the original eight breeding colonies. The remaining colonies face threats from stoats and erosion exacerbated by deer, goats, and pigs. The 2016 Kaikōura earthquake also caused significant damage to the largest colony.

Artificial colony

An artificial colony, Te Rae o Atiu, was established on the Kaikōura Peninsula to bolster the population. Chicks from the Kowhai colony were translocated and hand-fed in artificial burrows to encourage imprinting on the new site.

Crash-landing (fallout)

Hutton's shearwaters are prone to crash-landing in the town of Kaikōura due to disorientation by bright lights at night. Community volunteers rescue these birds, with a high success rate of release back into the wild. Efforts to reduce light pollution, including a bid for an international dark sky reserve, aim to mitigate this issue.