The Common Loon

What would a fishing trip be up north be without the hearing the echoing call the loon? It is at times a lonely, haunted call and at other times a maniacal laugh. It is the sound of the north. It is a familiar species that we all feel we know. However, as more and more research is done we are learning that the Common loon is a more complicated bird than we thought and some of the long-held beliefs about it are changing.

- Dave Taylor

The Common loon, Gavia immer; has a widely spread range that closely matches the boreal forests across the top of North America, Europe, and Asia. In Europe, it is known as the Northern Diver. It is one of five species of loons found around the world. All of them nest in the north and all are found in North America. The other species are the Pacific loon, Gavia Pacifica; the Red-throated, Gavia stellate; the Arctic or Black-throated loon, Gavia arctica; and the Yellow-billed loon, Gavia adamsii.

It was once thought that the Common loon mated for life but we now know that this is not the case. Their social lives are very complex and fascinating. During the breeding season, pairs are monogamous. DNA studies have shown that the resident pair are the parents of the hatchlings. This is not necessarily the case with other birds as there is often a fair amount of cheating going on, with females cheating on their male, and males cheating on their female. The Red-winged blackbird is a classic example of this sort of behavior.

Once paired on a territory, loons are true to each other but observers often noted the presence of other males spending time in the territory held by the breeding pair. If these interlopers were not there to breed with the resident female why were they there?

Young three to four-year-old birds may be breeding but if so, they tend to breed on inferior lakes where the survival of the young is not high. Other loons that show up in territories held by pairs are simply young adults without a place or a mate to call their own. They are known as “floaters”. From this group, members of both sexes make intrusions into more desirable territories to check them out. They usually stay for about 30-minutes and then are chased out by the resident loons, who swim out to intimidate the interloper with heads held high, head bows, splashes and circle dances. Floaters make between two and five of these incursions per day.