01 April 2021
Loons are excellent indicators of water quality as they require crystal-clear lakes (which makes it easier for them to see prey underwater) with abundant populations of small fish. Lakes with coves and islands are preferred as they provide cover from predators while resting and nesting. They also require lakes with enough surface area for their flapping-and-running takeoffs across the water. In their winter range along ocean coasts, they occur fairly close to shore and in bays and estuaries. They are only rarely found more than several miles offshore. Some Common Loons winter inland, on large reservoirs and slow-moving rivers. Common Loons that migrate across interior North America find large lakes and rivers to move between on their way north and south.
Diet consists of mostly fish, particularly perch and sunfish on their northern lakes. If fish are scarce or water is too murky for fishing, they will catch crustaceans, snails, leeches and even aquatic insect larvae.