Since 95% of Biscayne National Park is water, the majority of the animals are associated with ocean or shoreline habitats. The park is home to many threatened and endangered species including the West Indian manatee, eastern indigo snake, piping plover, American crocodile, peregrine falcon, Schaus' swallowtail butterfly, least tern and five species of sea turtle.
The Schaus' swallowtail is a large, colorful butterfly (see the image above) that is endemic to southern Florida. The state listed the butterfly as an endangered species in 1975. It was listed federally in 1984 when estimates showed only 70 or fewer adults remaining. Today the butterfly is only found on northern Key Largo and several small Keys in Biscayne National Park. In recent years the population declined so severely that emergency actions were required to try to prevent this species from going extinct.
The least tern was listed by the State of Florida as a threatened species in 1975. Much of the cause of their population decline is due to habitat destruction and encroachment. The birds nest along coastal or island beaches covered with sand, shells, or small stones. In 1995, two least tern nests were observed on the park's Soldier Key, each containing two eggs.
Sea turtle populations continue to decline throughout the world and within the United States due to loss of nesting beaches, feeding habitat, mortality through by-catch of the longline and shrimping industries, hunting for meat and poaching of eggs. Loggerhead and occasionally hawksbill sea turtles use the few sandy beaches that exist in the park as sites to lay their eggs. An average of 13.3 nests is laid each year with an average clutch size of 50 eggs. The park's sea turtle nesting program consistently monitors five beaches for activity throughout the nesting season. Protective screens are placed on the nests to protect the eggs from predation by raccoons. Click to learn more about sea turtles and park efforts to conserve them.