In late autumn, generally well before the great freeze, loons congregate on large lakes and fly south together. Young and immature loons are believed to spend two or three years in coastal waters before making their first trip back to the North Country. Loons are territorial birds and generally only one pair is found on each lake, except for very large bodies of water where several pairs inhabit the lake. Research conducted by Wisconsin Project Loon Watch indicates that loons inhabit bodies of water as small as nine acres. This is a social preparation to migration.
Loons feed primarily on fish, frogs, crayfish, mussels, leeches, and aquatic insects.
By the end of summer the young fledglings are capable of feeding themselves. Once airborne, loons are powerful fliers. Pilots have checked them flying at speeds up to 80 mph. It is assumed that loons return to the same lake every year. Males claim the same territory and await the female's return.