Abstract
The density of nesting burrows of the Wedge-tailed Shearwater Puffinus pacificus was measured in 224 quadrats on Heron island, Great Barrier Reef. Field measurements of the unconfined compressive strength of the soil material were made for each quadrat. Lowest burrow densities occurred in quadrats at both upper and lower ends of the soil strength range, increased burrowing success at sites where soil is not so loose as to collapse, but not so compacted as to inhibit burrowing is indicated. .Island development which results in soil compaction may, therefore, inhibit P. pacificus nesting.