The refuge is characterized by a thorn scrub habitat with rocky coastline surrounded by spectactular reefs. A lighthouse (still maintained by the United States Coast Guard) stands over 45 acres (180,000 m2) of cactus and grassland. The island was transferred to the United States Fish and Wildlife Service due to "its value for migratory birds." The U.S. Navy transferred some lands in 1969 and the remainder was received from the Coast Guard in 1981. The surrounding waters contain reefs and a shipwreck that attract large numbers of snorkelers, divers, and boaters.