Common Loons occur across Alaska, Canada, and the northern tier of the United States, but the common loon is not as common in the Western States as the name implies. Breeding pairs are found in only four states west of the Mississippi River, including Wyoming, Montana, Idaho, and Washington. In Wyoming, common loons nest in the far western corner of the state. In Idaho, they nest in lakes near the Canadian border. In Washington State, common loons nest in the far northwestern corner of the state near Puget Sound on the western side of the coastal range, and a few nest in eastern part of the state.
Loons also migrate through Montana in route to Canadian lakes and can be observed on large reservoirs and lakes in many parts of the state during the spring and fall seasons. Some examples of migratory stop-over sites include Pablo National Wildlife Refuge and Flathead Lake in northwestern Montana, Clark Canyon and Canyon Ferry Reservoirs in southwestern and central Montana, and Fort Peck Reservoir in northeastern Montana. Migrating loons are also occasionally sighted on large rivers such as the Missouri and Yellowstone.
Migrating Common Loon on Eureka Reservoir near Choteau, MT.
Photo Credit: Dave Hanna
Common loons migrate in loosely formed groups of a few birds that don’t consistently fly near each other. A group of loons is called a raft of loons. During migration, common loons have stop over points where they “raft-up” together and are often seen in groups resting and feeding on lakes or on large, slow moving rivers.
Montana has the largest population of common loons west of the Mississippi River with approximately 200 birds. These include about 65 nesting pairs (130 birds), an average of 40 chicks hatched in summer, and a few bachelor birds.
Montana’s Nesting Loons
Common loons return to Montana in late April to early May. Male and female loons wear the same plumage, so from a distance it is difficult to tell a male loon from a female loon. However, the male loon is slightly larger with a slightly larger bill. In addition, a male loon has a pronounced bump on its forehead. A female loon is slightly smaller and has a more sloping forehead. Can you tell which is which in this photograph?
Loon pairs do not mate for life. However, they have a strong fidelity to a lake, so they usually return to the same lake they nested on the previous year and often have the same mate. If one or the other does not return to the lake in spring, they will pick another mate, which may be a younger bird that has reached maturity.
By mid-May, most loon pairs have chosen a mate and a nest site. Of the 65 pairs in Montana that attempt to nest, only 25-30 pairs successfully hatch and raise 1-2 chicks each year. Nests are usually on small islands in marshy areas such as bays, coves, inlets or backwaters. The loons’ nesting season in May and June is the most CRITICAL TIME. Loons aren’t like ducks and geese that have large broods. Loons only lay 2 eggs, which both parents take turns incubating for 28-29 days.
Before the chick migrates it must learn how to fly. First it practices take off and landings. To become airborne a loon runs across the surface of the water flapping its wings. Its water runway might be up to a quarter of a mile long.
However, a loon chick remains on the ocean for three years. In the third winter of its life it will molt to its first set of adult breeding plummage and return to its natal lake. Only about 1 in 5 chicks (about 20%) survive its first three years of life to return to Montana.