A recent report on the welfare of the common loon shows a significant decline in population over the past 20 years. The Canadian Lakes Loon Survey 1981-2012, released in July 2013 by Bird Studies Canada, draws a link to acid rain and mercury poisoning for decreased reproductive success.
Loons make a pretty picture, but it is impossible to spend much time in their presence without being further impressed. As a life-long cottager who prefers a paddle to a motor, I have had many sustained encounters with them over the years, especially during my teens. I am struck by their expressiveness, vivid social interaction and intelligence. Their vocalizations, while heartrendingly beautiful, are also complex and, to my intuition, communicate more than humans might suspect. Loons seem capable of recognizing and remembering individual humans.
I have not had much time to spend at my cottage in Central Ontario in recent years, but hopefully that situation is changing. I just returned from nine days at the cottage, in which I had ample opportunity to canoe and explore old haunts.
On my first outing I had just begun to reflect that I had not yet heard from the loons. With that four adults appeared, swimming parallel to my path. Within a few minutes they met three more and commenced a common social behaviour in which they dive all at once and presumably corral fish. I witnessed a second meeting later in the week, but then it progressed into aggressive vocalization and physical displays. On another occasion I found two adults alone on a much smaller, adjacent lake.
Loons typically mate for life. They are fiercely territorial. However, I believe they continue this social fishing behaviour in areas sufficiently removed from nest sites.
My lake is quite large. At certain times in the past, I have been aware of at least three mated pairs occupying different parts of the lake with a fourth on a nearby lake. This year unfortunately I did not see any juveniles, but of course they may still be present.
I do not have a figure for the number of freshwater lakes in Canada, but for Ontario alone it is about a quarter of a million. I hope that everyone who explores the Canadian Shield might encounter this essential player in lake ecology, the common loon. Note that their position high in the food chain makes them vulnerable to concentration of mercury poisoning. This effects their behaviour and reduces reproductive success.
About 95 percent of common loons nest and breed in Canada, so Canadians have a special responsibility to protect them. Anyone interested in conservation can participate in the Canadian Lakes Loon Survey. Previous generations of volunteers have shown how citizen scientists can gather valuable information and help protect the loon. We also need better environmental legislation to combat mercury and acid rain pollution.
Here is also a success story about a family who built a nesting platform. A pair of returning loons used it to raise young for five successive years.
Years ago at my cottage, a loon family adopted our previous floating raft, which had become overgrown with water mint, sweet gale, sundew, sedges and other wetland plants. Unfortunately the site was fairly exposed and drew too much attention from nosy human neighbours.
However, it was loon territoriality that ultimately doomed the nest site. The second spring it fell to a dispute. The original pair showed up, established a nest and laid two eggs. Then another male approached and a violent fight ensued.
Rivals are known to attempt to drown one another, and often the stronger, younger individual succeeds. One of our males was gravely injured or perhaps killed. In any case, the pair abandoned the nest and never returned.