Hutton's Shearwater

Appearance

A medium-sized (350 g) seabird, with a 75 cm wingspan, it is brown with a white underbelly and brown collar, dark borders to the underwing, dark grey bill, and pinkish dark-webbed feet. It can be distinguished from the fluttering shearwater by its dark grey "armpits".

Published measurements include mass about 364.

Although the species was scientifically described in 1912, its breeding colonies were only rediscovered by Geoff Harrow in 1964.

Range and habitat

There have been individual sightings around the entire New Zealand coast, but most birds feed off the eastern South Island, especially between Cook Strait and Banks Peninsula. Outside the breeding season, they are mostly found in Australian waters. Hutton's shearwater is a medium-sized ocean-going seabird in the family Procellariidae.

Its range is Australian and New Zealand waters, but it breeds only in mainland New Zealand. Conservation measures for the bird include predator control at the breeding sites, establishing the Kaikōura Dark Sky Sanctuary, and community initiatives to rescue birds that crash-land at night on streets in Kaikōura.

Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.

Diet and breeding

Hutton's Shearwater have long bills, that are adapted to catch prey more or less underwater by plunging from a few metres above the surface or by paddling slowly forwards searching with their head submerged, then diving using partly opened wings for propulsion. Hutton's shearwater feed on what is available within 50 m of the surface and this can range from small fish to crustaceans, krill and cephalopods.

Using GPS trackers on adult birds from the Kaikōura Peninsula colony, four main foraging locations have been identified with two being coastal (Pegasus Bay and Canterbury Bight) and two over oceanic banks (Mernoo Bank and Urry Bank). All the foraging locations were approximately 125-365 km south or south-east of the colony and near Banks Peninsula. Uniquely amongst seabirds, Hutton's shearwater breed in sub-alpine to alpine zones, making them one of the few New Zealand seabirds to breed solely on the mainland.

In crisis

Its conservation status is Endangered, because there are just two remaining breeding colonies, located in the Seaward Kaikōura Range. Six other shearwater colonies have been destroyed by introduced pigs. A protected breeding area has also been created on the Kaikōura Peninsula, among them a pest-exclusion fence and man-made burrows, with the initial population established by translocating fledglings from the remaining breeding colonies.

The breeding birds' main predators are introduced stoats, that 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.

Hutton's Shearwater is Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.

Sources

Written for this catalog from the English Wikipedia article on Hutton's Shearwater, Wikidata item Q1261199. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.