Stock Photo: A melanistic / genetic variant of Green_backed Heron Butorides striatus on the island of Cayo Santa Maria in Cuba´s Jardines del Rey archipelago a UNESCO World Biosphere. The International Union for Conservation of Nature IUCN believes that this is the fi. A melanistic / genetic variant of Green_backed Heron Butorides striatus on the island of Cayo Santa Maria in Cuba´s Jardines del Rey archipelago a UNESCO World Biosphere. The International Union for Conservation of Nature IUCN believes that th