Loons are a long-lived bird. The oldest known common loon lived 18 years but their lifespan may be 25-30 years. Their appearance is similar.
Males are generally larger than their mates.
Loon calls are used to communicate among family members and to maintain territories during the breeding season. In the continental U.S., surveys indicate the largest population is in Minnesota at about 10,000 adults. Wisconsin has an estimated summer population of about 2,200 adults. Loons return to northern forested lakes and rivers in the springtime, usually in April. The breeding range includes Alaska and northern Canada south to Washington, Montana, Minnesota, WIsconsin and New Hampshire.