Island Treasure (Cedar Bks.)

Mark was the first of the five boys to top the last sand dune, and to see the super yacht anchored in the bay. But as the occupants of the yacht watched the boys through binoculars, they weren't very pleased to see >them< on the island. When the boys met the "ornithologists" from the yacht, Eric thought there was "something fishy" about them, especially after they sent the boys on a wild goose chase for a sea-eagle!