Purple martins have roosted on Bomb Island in Lake Murray every summer for decades to prepare for their annual migration to South America. Numbering at least in the tens of thousands, if not more, the birds gather at dusk in great clouds around the island as they return from a day’s hunting for beetles, dragonflies and other high-flying insects. To naturalist Rudy Mancke, the birds are a wonder of nature. More than that, people have gathered around the island in boats each summer for years, and the phenomenon of this huge mass of birds has become a tourist attraction. Mancke admires the birds' abilities and comments that humans have used them for pest control for centuries. Janie Baker of Lake Murray Country Tourism and boat operator Ken Jones talk about the tourism magnet the birds have become and the awe that they inspire in visitors to the lake outside Columbia.