The east coast of Newfoundland, Canada, harbours some of the largest Leach's Storm-Petrel Oceanodroma leucorhoa colonies in the world. In 1997, we estimated the breeding population of Leach's Storm-Petrels on Great Island, Witless Bay, Newfoundland at 269 765 ± 27 769 (213 866 - 325 664) pairs. This is similar to a previous estimate from 1979 of 252 910. A shift in distribution has occurred with more petrels nesting in forested habitat and fewer in grass shrub meadows in 1997. Gull predation on seabirds has increased in Newfoundland in the 1990s as a response to a variety ofchanges in the marine ecosystem. We estimated that gulls killed 49189 Leach's Storm-Petrels in 1997. However, in the face of this large kill, the breeding populations does not appear to have substantially declined. Recruitment from other large colonies may be maintaining the breeding population on Great Island
