About the Refuge

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Green Cay NWR, St. Croix, was established in 1977 to protect the endangered St. Croix ground lizard (Ameiva polops). The refuge consists of the entire 14-acre island of Green Cay. The refuge’s establishing purpose was to conserve “fish or wildlife which are listed as endangered species or threatened species.” The refuge extends only to sea level and does not include any of the submerged marine habitat, including coral reefs which surround the island.

Outcrops of lava, tuffs, and breccias are prominent terrestrial geological features. Pre-historic archaeological conch shell middens (discarded conch shells) once occurred on the shoreline. Estimated to contain as many as 33,000 shells, these middens demonstrated 1,000 years of human use or occupancy, dating back to as early as 1020 A.D.


This island refuge provides critical habitat for the largest remaining natural population of the federally endangered St. Croix ground lizard. Its extirpation from the main island of St. Croix, just several hundred yards away, is generally attributed to the modification and loss of shoreline habitat resulting from human activities, and the introduction of predators, such as mongoose, rats, cats, and dogs. The introduction of the exotic Indian mongoose likely completed the elimination of the species from St. Croix. As a result, this species is one of the rarest reptiles in the world and is unique to St. Croix island ecosystems.