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Status: Population size: 2.5 million Photo by Glen Tepke.

Buller's Shearwater
(Puffinus bulleri)

This elegant seabird is sought after by North American birders who must take offshore boat trips from the Pacific coast during the late summer and fall in order to see it in North America. Amazingly, the species breeds on only a few small islands in New Zealand but travels to the Pacific coast of North America during its nonbreeding season.

Identification
Large shearwater with slender body, brownish-gray above edged with buff-gray to suggest frosty appearance grading to blackish-brown rump. White below, creating a striking contrasting pattern unlike any other Pacific shearwater. Legs and feet pinkish. Flight graceful and measured. Sexes alike.

Distribution and Population Trends
Transpacific migrant, breeding only in the Poor Knights Islands, New Zealand where the bulk of the population occurs on just two islands. In fall, it migrates east across the Pacific, from Japan to North America. Birds appear regularly off the Pacific coast of the U.S. and Canada from August to October with single day pelagic trips from California to Washington sometimes counting over a hundred individuals.

Ecology
A bird of the open ocean. Breeds at its New Zealand island colonies in August and September. Small numbers remain in the northeastern Pacific during the winter. Nests in burrows and crevices in rocks and ledges, under tree roots, frequently under dense vegetation. Diet consists of krill, small fish, squid, and jellyfish.

Threats
The species was previously caught in drift nets in the North Pacific with an estimated 4,000 birds killed annually and may be still be at risk from set nets. Long lines, trawling operations, and hand-and-reel lines are still a threat, though there is little documented evidence to this effect. The species' very limited breeding range makes it very susceptible to a catastrophic decline from introduced predators, disease, storms, or other factors.

Conservation
Eradication of feral pigs from some of its breeding islands in new Zealand resulted in a dramatic population increase on those islands in 1936, probably due to recolonization of birds from predator-free island of Tawhiti Rahi. A conservation plan should include a complete census to assess the status of the population on Simmonds Island, identifying signs of prospecting on other island groups, and establishing a monitoring program on Poor Knights Island to assess the rate and pattern of colony expansion. In its non-breeding range, efforts to decrease mortality from fisheries should continue as should other efforts to protect the health of the marine ecosystems upon which it depends.

References
BirdLife International. 2000. Threatened Birds of the World. BirdLife International and Lynx Edicions, United Kingdom.

Harrison, P. 1983. Seabirds: An Identification Guide. Houghton Mifflin Company, Boston, MA

Kaufman, K.. 1996. Lives of North American Birds. Houghton Mifflin Company, Boston, MA.