Monotypic
Also known as Ashy-backed Shearwater, Grey-backed Shearwater and New Zealand Shearwater. Named by Salvin in honor of Sir W. L. Buller (1838-1906) author of the Birds of New Zealand who collected the type specimen.
 

Identification

A smartly patterned, slender-bodied Pacific Shearwater. Flies in low winds with measured wingbeats on bowed wings followed by long glides close to water. In stronger wings, glides higher with fewer flaps. Feeds mainly by surface-seizing and will join feeding flocks. Will attend active trawlers. Will dive for sinking food. Jizz and size similar to Wedge-tailed Shearwater.

Figure 1 Ventral view of a Buller's Shearwater photographed on 22 August 1999 during a Shearwater Journeys trip to the Cordell Bank, California. Still image taken from a digital video. Copyright of Angus Wilson© 1999

Upperparts gray with a contrasting black 'M' mark. Striking broad white band across the secondaries and outer secondary coverts, paralleling and contrasting the black 'M' mark. Blackish cap running through the eye. Bright white underparts, contrasting sharply with the dark cap. This pattern is unique among shearwaters. Narrow dark underwing margins visible only at close range. Uniform gray uppertail coverts and dark tail feathers. Bill dark and feet pink.

Figure 2 Dorsal view of a Buller's Shearwater showing the distinctive combination of black, brown, white and gray. Still image capture from digital video taken on 23 August 1999 near Point Arena, California. Copyright of Angus Wilson© 1999
 

Where and When

Breeding confined to islands off the North Island of New Zealand. Estimated population c 2.5 million birds. Recent increase on Poor Knight's Island after removal of feral pigs. Breeding season birds range throughout the subtropical waters of New Zealand and into the Tasman Sea, regularly reaching se mainland Australia. Outside of breeding season, makes a trans-equatorial migration to the North Pacific becoming widespread off Japan, the Russian Far-east and western North America. Depart from breeding islands in mid-late May, and first returning in early September. Irregular off the coast of South America and the Galapagos Islands. Occupies a wide range of marine habitats from well inshore to the shelf edge and deep pelagic waters.

One remarkable record from the North Atlantic, of a bird photographed off New Jersey.

Figure 3 Resting Buller's Shearwater, 25 August 1999 near Bodega Head, California. Appears longer necked than in typical flight and rides high on the water. Copyright of Angus Wilson© 1999
 

Photographs on the web

Excellent flight shot showing upper surface September, Monterey Bay. Photo by Jerry R. Oldenettel.

Upperparts in flight Photographer unknown.
 

Literature