Diel changes in numbers of seabirds occupying Cays on the Swain Reefs, Great Barrier Reef, Australia

Seabirds were counted during four 24-hour periods, two in summer and two in winter, on each of two cays (Price Cay and Frigate Cay) in the Swain Reefs, Great Barrier Reef, Australia. There were six breeding species of seabirds and 13 nonbreeding ones. Each species showed its own pattern of diel change in number of individuals on the islands, some being more numerous by day, others by night. For a given species, there were differences between seasons and between islands.