Figure 1

Locations of breeding grounds, nearest neighbour relatedness and breeding timing classes of sooty terns on Ascension Island. Inset map of Ascension Island (top left) shows the locations of the two sooty tern breeding grounds at Mars Bay and Waterside. The locations of 12 individuals significantly more genetically related to their four nearest neighbours than those selected at random from the population are shown within sampling points (marked with Xs). Sampling points are coloured by breeding timing classes with Class 1 being the earliest breeders and Class 4 the latest.