Wood storks stop for nourishment. Seaside sparrows nest in huge numbers and neotropical birds stop for food and shelter during spring and fall migrations. Over 260 birds species have been logged on the refuge. Christmas bird counts of 100 species are typical. Over 300 alligators have been tallied in August censuses.
Loggerhead turtles use the island's Gulf beaches to lay eggs in their buried nests.
Plants on the island include 15 species that are listed as threatened by the state of Florida. There is even a family of red wolves living on the island. The island was named in the 1600s by missionaries and ended up in the early 1900s becoming a private hunting ground with a collection of exotic game animals. The zebras and elands are gone, but the imported sambra deer still roam mostly in the island's marshes, leaving the drier land for the smaller white-tailed deer. Sambra deer are an elk native to southeast Asia and can weigh up to 700 pounds.