 Plume harvesting became a dangerous business . The Audubon Society became concerned with the amount of hunting being done in rookeries in the mangrove forests . In 1902 , they hired a warden , Guy Bradley , to watch the rookeries around Cuthbert Lake . Bradley had lived in Flamingo within the Everglades , and was murdered in 1905 by one of his neighbors after he tried to prevent him from hunting . Protection of birds was the reason for establishing the first wildlife refuge when President Theodore Roosevelt set Pelican Island as a sanctuary in 1903 . 
