There is no sound more closely identified with North Woods wilderness than the mournful wail of the common loon. Its scientific name is Gavia immer, which means “diving seabird.” The common loon lives in lakes and ponds all across Maine during the months of open water. Before freeze-up, adult loons and young of the year fly to the New England coast, where they overwinter. They have special salt glands, which enable them to eat fish and drink water from the ocean. The adults leave the lakes first and leave the juveniles behind, which sometimes results in the death of a juvenile if the lake becomes too frozen and they don’t have enough open water to take off. The loons that you see on Maine lakes are adults that have spent their first few years along the coast.
Each year, the Maine Audubon Society oversees the annual loon count by volunteers in about 400 freshwater bodies, mainly across southern, central, and downeast Maine. It is safe to say that Maine has thousands of resident loons, with a population larger than that of the rest of New England combined. Of course, Maine is as large as the rest of New England combined and has by far the best and most suitable loon habitat.
Estimated loon numbers have been increasing since the first loon count in 1983. All things being equal, the loon population has greatly increased and is very healthy. However, the growing number of loon sightings can also be explained, in part, by more participants counting on a greater number of water bodies. The number of loon chicks counted has remained relatively stable at 300-500. These figures may be indicative of decreased productivity per nesting pair or higher chick mortality. Overall, however, the annual recruitment appears to be sufficient to support a stable or increasing adult loon population.
The common loon is the oldest living bird species on earth, having existed for some twenty million years. Both males and females have virtually identical plumage, but generally the males are larger and have a slightly larger head. They spend practically their entire lives in water. They walk awkwardly because their legs are located near the rear of their body but are excellent flyers and swimmers. Unlike ducks and geese, which can instantly become airborne from land or water, common loons can only fly from the water. They use the water surface like a runway, flapping their wings and running across the water until they become airborne.
Loons are long-living birds and can live up to thirty years. This is a necessary survival mechanism because they do not begin breeding until they are about six years old and females typically lay only one and sometimes two eggs per year. It is uncommon to see a loon parent with two chicks.
Nesting success is low, with only about 40% of breeding pairs producing young each year. Predators or high-water conditions often destroy nests and eggs. Nesting typically occurs in May with both adults sharing in the duties of nest building. If incubation is successful, the eggs hatch 28 days after being laid. Most nesting occurs on islands, where they avoid predators and humans. Getting too close to a nest or harassing the loons from a boat can cause the female to abandon it. I once was canoeing on a pond in northern Maine when I paddled next to a tiny island of no more than fifty square feet. It wasn’t until I was right next to the island that I looked down and saw a female loon on a nest crouching down below the vegetation to avoid being seen. I left the area immediately with the loon still on the nest.
Breeding loons are very territorial. They are monogamous for much of their adult life, but they will change mates if one dies or one is driven away by another loon. When you’re out on a lake in Maine, you usually see only one or two loons together. In late summer, however, it is common to see loons in groups of a dozen or more called “rafts” or “asylums” (no pun intended). These rafts are usually made up of non-breeding loons. I have seen rafts of loons swimming in unison in circles as if they were on a merry-go-round. The reasons for this gathering are unknown.
Loons will eat just about anything that swims. While trout fishing on a Canadian lake, I had a loon swim under and all around the boat trying to take trout off my hook as I was reeling them in. Fortunately, I did not catch it.
There are many threats to loon survival. Many eggs do not hatch. Of those that do hatch, young loons are vulnerable to snapping turtles and other predators. Human disturbance will often prevent successful nesting. One way of addressing this issue is to construct and place anchored nesting rafts away from high boat traffic areas. Research has shown that these artificial nesting platforms are quite successful.
The greatest threat to adult loons in Maine is lead poisoning through the ingestion of lead fishing tackle. To digest their food, loons will swim to the bottom and swallow gravel. Occasionally there are lead sinkers or fishing jigs on the bottom as well. The gizzard grinds up the gravel and the lead, and the loon eventually dies.
Welcome to Maine, and we’re glad to have you. We hope you enjoy our beautiful, clean lakes, but please remember not to use any fishing tackle that contains lead. We love our loons, and we want you to love them too. Even though Maine’s loon population as a whole appears to be increasing, lead poisoning results in an excruciating slow and painful death. One lead-poisoned loon is one too many.
