Crested Terns roosted throughout the year on both islets, but mainly on Seal Rock, usually as a single aggregation and often with White-fronted Terns. On Seal Rock their numbers varied erratically from less than 50 to more than 500, and in general the largest flocks occurred in late spring and summer.
Silver Gulls were alert to any activity at sea nearby, flocking to investigate feeding by Crested and White-fronted Terns or the commotion caused by a Great White Shark Carcharodon carcharias preying on a seal at the surface, or a seal thrashing a large fish.