Flightless bird that require a significant amount of overall metabolic energy, ratites decrease their basal metabolic rate and conserve energy. A study looking at the basal rates of birds found a significant correlation between low basal rate and pectoral muscle mass in kiwis. On the contrary, flightless penguins exude an intermediate basal rate. This is likely because penguins have well-developed pectoral muscles for hunting and diving in the water. For ground feeding birds, a cursorial lifestyle is more economical and allows for easier access to dietary requirements. Flying birds have different wing and feather structures that make flying easier, while flightless birds'
Draining and development of the Everglades York paid at least 60 hunters to provide him with "almost anything that wore feathers, but particularly the Herons, Spoonbills, and showy birds". Hunters could collect plumes from a hundred birds on a good day. 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.