General

Buller’s Shearwater: Medium-sized shearwater with gray upperparts and white underparts. Dark gray M-pattern is visible across upperwings and back in flight. Head has white face, black cap, upper ear coverts brown-gray, white line surrounding base of eye, sometimes has a short posterior eye stripe, sometimes a nearly complete white eye ring; black bill; iris is dark gray-brown. Tail is large, long and black; legs are pink. Sexes are similar. Female is slightly smaller, especially the bill. Juvenile is like adult.

Range and Habitat

Buller's Shearwater: This species breeds on islands of the Poor Knights group north of New Zealand, especially on Tawhiti Rahi and Aorangi. It is a trans-equatorial migrant, and a regular summer visitor to north Pacific, appearing off west coast from Aleutian Islands south to California. These birds are pelagic, coming ashore only to breed.

Breeding and Nesting

Buller's Shearwater: These birds return to the Poor Knights Islands in mid-September to court females and clean out their burrows before breeding. Nesting occurs in large, dense colonies with egg-laying beginning in October. One white egg is laid in a burrow or rock crevice lined with leaves, twigs and pebbles. Both parents incubate the egg for 51 days. Most chicks fledge at around 90 days.

Foraging and Feeding

Buller's Shearwater: These shearwaters land on the water to pick food up from the surface. Sometimes they duck their head beneath the water to snatch food. Their diet consists of krill, small fish, squid and jellyfish. They have only recently started to scavenge fishing boat scraps. These birds rarely dive under water.

Vocalization

Buller's Shearwater: Generally silent at sea. High-pitched wails and howls near breeding colonies.

Similar Species

Buller's Shearwater: Black-vented Shearwater is smaller and has plain upperwings.