Dramatic and immediate improvements in insular nesting success for threatened sea turtles and shorebirds following predator management

Predation critically threatens reproductive success of sea turtles and shorebirds at many of Florida's beaches. We examined the biological and bioeconomic results of predator management on two adjacent barrier islands, Cayo Costa and North Captiva, along Florida's west coast. Both islands suffered severe nesting losses due to predation and disturbance due to raccoons, while Cayo Costa also was impacted by a large population of feral swine. In 2006, our initial year of study, neither island received predator management and no least tern production occurred on either island, and sea turtle nest predation was 74% and 60%, respectively, for Cayo Costa and North Captiva. Predators were managed in 2007 on Cayo Costa while North Captiva served as an untreated reference island. North Captiva again had no least tern production and sea turtle nest predation was 84%. In contrast, Cayo Costa produced 31 least terns and sea turtle nest predation plummeted to 16%. Both islands received predator management in 2008 when Cayo Costa and North Captiva respectively produced 20 and 55 least terns and had 15% and 0% sea turtle nest predation. The entire costs for predator management by experts over the course of the study was $USD 39,636, while the returns in additional production of least tern young and hatchling sea turtles was valued over $USD 1.1 million for a resulting benefit–cost ratio of 27.8.