Midriff Island Region

The Midriff Islands include Isla Tiburon, the largest island in Mexico. These islands are home to endemic species, such as the San Esteban Chuckwalla. Many islands in this region are breeding grounds for seabirds, Isla Alcatraz, for example, is the nesting site of 14 species of waterbirds including the federally threatened Craveri’s Murrelet. Isla Rasa is the breeding ground for 350,000 Heermann's Gulls and 200,000 Elegant Terns, which constitutes at least 95% of the world's population of both species. Additionally, many of the islands support large California Sea Lion rookeries, such as San Esteban Island which is the most important reproductive colony of Sea Lions in the Gulf of California.