The Common Loon is a symbol of wilderness. Many feel the stirring of the wild when they hear its rich yodeling or mournful tremolos in the north woods. It can be seen from time to time along the Edmonds waterfront, mostly fall through spring when it is silent. Its basic plumage, as seen in winter (third photo), is drab. It is the largest of the three loon species regularly seen in Edmonds waters.
Diet is varied. Fish include minnows, suckers, perch, shad, rock cod, and killifish up to about 10 inches in length. Crustaceans, mollusks, frogs, leeches, and aquatic insects also are part of the loon’s diet. It will sometimes consume aquatic plants such as algae and pondweeds. It forages by diving and swimming underwater, propelled by its large feet. It will swallow smaller items while underwater and bring larger prey to the surface before eating it.
Older sources state that the Common Loon first breeds at age 2. More recent references suggest that age six is when this species first breeds. That may explain why this loon occasionally can be seen in summer, in its breeding plumage (first and second photos), along the waterfront. Nonbreeding birds would not necessarily migrate to northern breeding lakes.
The Common Loon is monogamous for a period of about five years. The male and female arrive separately on the pair’s breeding lake. Breeding lakes are in coniferous forest zones in the northern latitudes. They are also found on open tundra. Breeding lakes must be large enough to accommodate the distance a Common Loon needs to take flight. Depending on wind, a loon needs from 30 yards to a quarter mile to gain enough speed for lift-off. To reach that speed, the loon runs across the water’s surface, flapping its wings.
The male selects the nest site in a quiet, protected hidden spot of lakeshore. The pair builds its nest together. It is a mound of plant materials such as sedges and marsh grasses that grow along the lake’s edge. One of the pair will then crawl on top of the mound and shape the interior to the contour of its body. The nest may be reused in subsequent years. This species will use artificial nest platforms on lakes with extensive shoreline development.
The female lays two eggs, which are incubated by both sexes for almost a month. The young leave the nest one or two days after hatching. By two or three days of age they can dive and swim underwater. Both parents tend and feed the young while they are small. Sometimes a young bird will ride on its parent’s back. They are capable of flight at 10 – 11 weeks of age.
The adult birds start migrating south when the young are about 12 weeks of age. Juvenile loons gather in flocks on northern lakes and start their journey south a few weeks later. There are a number of collective nouns for a group of loons: asylum, cry, loomery, raft, and water dance. While the Common Loon is an agile swimmer, it is also a fast flyer. Migrating loons have been clocked at air speeds in excess of 70 mph.
The oldest known Common Loon was at least 25 years of age when it was spotted in Wisconsin and identified by its leg band.
For conservation purposes the Common Loon is considered a bird of least or moderate concern. The North American population is stable and healthy. Nonetheless, this species requires clear, unpolluted lakes with abundant fish for breeding. It remains vulnerable to pollution and other disturbances. Lead fishing sinkers have caused many deaths by lead poisoning. A Common Loon will dive to the bottom of its breeding lake and scoop up pebbles to store in its gizzard. That is when it will ingest lead sinkers. Coal burning has also caused mercury contamination of breeding lakes and that, in turn, has led to reproductive failure. Motor boats on breeding lakes can also disturb loon nesting.
— By Carol Riddell
Carol Riddell manages the bird education displays, on behalf of Pilchuck Audubon Society and Edmonds Parks & Recreation, at the Olympic Beach Visitor Station.