Buller’s Shearwaters have been observed on pelagic surveys off the British Columbia coast, from late May through early November. They are most common, primarily seaward of the continental shelf, especially in August and September (Kenyon et al. 2009). Globally, the population is estimated at 2.5 million individuals (Marchant and Higgins 1990), however this number is now suspected to be an over-estimate (BirdLife International 2012). Nesting is restricted mostly to two main islands, Aorangi and Tawhiti Rahi, and five other islets in the Poor Knights Islands in the north of New Zealand. At Aorangi, introduced pigs ran wild after abandonment by local Maoris in 1823. Only about 100 inaccessible cliff-side burrows of the shearwaters were untouched by the feral pigs. After the feral pig extirpation in 1936, the Aorangi population increased to an estimated 200,000 pairs by 1981. It is suspected that the global population is either stable or decreasing (Taylor 2000, BirdLife International 2012). The Buller’s Shearwater has not been sufficiently monitored in Canada to reliably determine a change in population status relative to 1970; a population goal has therefore not yet been determined.
