Nearest Neighbour Analysis and Wedge-Tailed Shearwater Burrow Patterns on Heron and Masthead Islands,Great Barrier Reef

Heron and Masthead Islands in the Capricorn Group of the Great Barrier Reef Marine Park support major nesting colonies of the wedge-tailed shearwater. The distribution pattern of shearwater nesting burrows was established for particular habitats on both islands by means of a nearest neighbour analysis. Areas of Pisonia grandis forest had the highest burrow density and near-random distribution patterns for burrows while the island fringes had the lowest densities and higher degrees of aggregation. These results may reflect the importance of social communication within a wedge-tailed shearwater colony. Burrows are distributed in patches around the margins of the colony where clear and fringe habitats are represented, but randomly near the centre in Pisonia areas, where sheer numbers may negate the need for further aggregation.