These heavy bones make loons less buoyant and help loons to dive. The loon's large webbed feet, not their wings, provide propulsion underwater. A Day in the Life of a Loon Loons spend their days hunting, feeding, resting, preening, and caring for young. Their diet in summer consists of fish, crayfish, frogs, snails, salamanders, and leeches. Adult loons prefer fish to other food, and seem to favor perch, suckers, catfish, sunfish, smelt, and minnows.
Loons spend long rest periods motionless on the water.
They may rouse themselves to stretch a leg or wing at intervals, occasionally comically waggling a foot above water. Loons peer underwater and move their heads from side to side to locate prey. During dives, loons compress their feathers and force air from between their feathers and from the air sacs in the body. Losing air also allows loons to quietly sink below the water's surface to avoid danger. Adult loons may fly to different lakes to feed, but the adaptations that make loons such efficient divers also make them heavy and slow to take wing.