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. Breeding loons, like those radio-marked in this study, left breeding areas in late October to early November.
Loons spend the winter season along the Atlantic, Pacific, and Gulf coasts.
The telemetry data tracked the birds every 2-3 days during migration. In one documented case, a loon traveled 572 miles over a 3-day period. In another case, a loon traveled consecutive distances of 388 and 419 miles, each during a 2-day period. These were likely single movements. The distance between breeding and wintering grounds of the loons we monitored ranged from 1,171 to 1,318 miles.