Most visitors to the reef focus their attention underwater. But there are also sights to be seen in the air, as more than 215 species of seabird frequent the reef and its islands. Many birds stop in the region on their annual migration, and some live here year round in vast colonies. It's estimated that 40,000 sooty terns, brown boobies, common noddies and other species make their home on Michaelmas Cay during mating season. From the deck, you can watch thousands of gulls and other seabirds feeding on schools of fish. Be sure to keep your camera handy.