Buller's shearwater is a Pacific species of seabird in the family Procellariidae; it is also known as the grey-backed shearwater or New Zealand shearwater. A member of the black-billed wedge-tailed Thyellodroma group, among the larger shearwaters of the genus Ardenna, it forms a superspecies with the wedge-tailed shearwater.
Region
Pacific Ocean
Typical Environment
Breeds on the predator-free Poor Knights Islands off northeastern New Zealand, nesting in burrows on forested slopes. After breeding, it disperses across the North Pacific, commonly ranging along the California Current, the Gulf of Alaska, and into the western North Pacific near Japan. At sea it is strictly pelagic, favoring open-ocean waters far from land. It often concentrates along productive fronts and upwellings and may gather in large rafts. Occasional sightings occur off the west coasts of North and Central America during migration.
Altitude Range
Sea level to 100 m
Climate Zone
Temperate
Ease of Keeping
Beginner friendly: 1/5
Buller's shearwater is a large Pacific shearwater that breeds almost exclusively on New Zealand's Poor Knights Islands and ranges widely across the North Pacific outside the breeding season. It uses dynamic soaring, carving long, low arcs over waves to conserve energy while traveling vast distances. Though its global numbers are sizable, reliance on a single breeding locality makes it vulnerable to stochastic events and introduced predators, so conservation management of its nesting islands is crucial.
Buller's shearwater in Leigh, New Zealand; note upperwing pattern
Temperament
social and active
Flight Pattern
dynamic soaring with long glides and few wingbeats
Social Behavior
Highly colonial, nesting in dense burrow colonies under forest or scrub. Pairs are largely monogamous and return to the same burrow annually, laying a single egg. Both sexes share incubation and chick-rearing duties, visiting colonies mainly at night to avoid predators.
Migratory Pattern
Seasonal migrant
Song Description
At sea it is mostly silent. At night in colonies it gives a mix of wails, cackles, and moaning calls, often in duets between mates, carrying over the colony in darkness.
