The Order Gaviiformes consists of loons, aquatic birds found in freshwater lakes and coastal waters of the Northern Hemisphere. Loons are excellent divers, using their webbed feet to pursue fish underwater, which makes them highly specialized predators. They have streamlined bodies, sharp bills, and dense bones that aid in diving, but these adaptations make them awkward on land. Loons are migratory, breeding in northern lakes during summer and wintering along coasts. Their haunting calls are distinctive and play a role in territory defense and mate attraction, making them iconic birds of northern aquatic ecosystems.