Harpswell Naturalist: An assist for common loons

The black-capped chickadee is our state bird, yet most visitors to Maine hope to see and hear a loon during their stay. Few sounds in nature are more memorable than the distinctive calls of a loon. I dislike calling Gavia immer “common,” but it serves to separate our birds from other loons in the Gavia genus: the red-throated, Pacific, and great northern loons. It is possible to see red-throated loons passing through here most winters, and a Pacific loon lingered in Down East waters this year, but the common loon is a reliable sight across Maine.

We all recognize the distinctive black-and-white summer plumage of the common loon and, during breeding season, their eyes turn from brown to dark red. The long black beak serves well for fast strikes at prey while underwater. A couple years ago there were reports of a bald eagle dying as a result of a strike to the chest from a loon’s beak, presumably during an attack on the loon’s nest. Adult loons weigh up to 12 pounds. They are ungainly in takeoffs and landings, needing to run along the surface to become airborne.

Loons are strong flyers capable of hitting speeds up to 70 mph. Underwater they excel, swimming and darting at high speed. Their head and neck are slim, the legs set well back on the body as with most diving birds, and they have large, webbed feet. Diving up to 200 feet, loons expel some air and flatten their feathers to reduce buoyancy and increase speed during 90-second dives. They use sharp points on their tongue and the roof of their mouth to hold slippery creatures. Fish make up the bulk of their diet, but they may take crayfish, frogs, salamanders, leeches, shellfish and aquatic plants.

While our loon population is currently stable, there are numerous risks for the birds. Acidic rainfall can lower the fish population in lakes where loons feed. Mercury from power plant emissions affects the ability of loons to reproduce. Discarded fishing line may leave a loon ensnarled and unable to escape. Even one lead sinker or shotgun pellet ingested into a bird’s gizzard can cause death. Fortunately, many states, including Maine, have banned lead sinkers, and waterfowlers switched to nontoxic shot pellets more than 20 years ago. The North American Waterbird Conservation Plan listed the common loon as a “species of moderate concern” with an estimated global population of 600,000.

The loons we enjoyed in winter have moved on, finding their way to inland lakes and ponds now free of ice. Others may breed as far north as the Canadian Arctic region. During autumn migration, loons may range far to the south. Some birds suffer as a result. In 2003, a barge ran aground in Buzzard’s Bay, Massachusetts, spilling oil that killed 200 loons. The 2010 Deepwater Horizon oil spill may have killed up to 1,000.

Fortunately, our state’s population has recovered from such losses, with Maine Audubon reporting 3,400 loons from Rangeley to Southern Maine in 2022, compared to 2,800 in 2017. But there are increasing concerns about the future of loons as waterfront development continues in Maine and recreational boating has surged after the COVID-19 pandemic.

Loons are loyal to breeding sites and prefer to use the same sites annually. In the buildup to breeding, loons can be very aggressive, with both males and females fighting to protect their territories. Once a pair forms, they participate in a graceful courtship dance, swimming in circles with each other and looping their necks together. Loons are ungainly on land, so they generally nest along the shore of islands or quiet coves in hopes of avoiding predators. Disturbance by humans in the quiet reaches of ponds and lakes may cause loons to abandon a nest and their young.

This year, Maine Audubon, the Maine Department of Inland Fisheries and Wildlife, and other partners are ramping up their public education efforts in support of loons. They are encouraging people to avoid disturbing the birds and their nest sites, while placing special covered floats in some waters to give loons more protection during nesting and rearing of chicks. Boaters are encouraged to avoid causing large wakes near sensitive shorelines. Greater public awareness and interest in loons is important to ensure that future generations can thrill to that haunting call wafting across a remote lake as the light falls in wild country.

Ed Robinson’s latest book, “Nature Notes from Maine Vol. II: Puffins, Black Bears, Raccoons & More,” is available from the Harpswell Heritage Land Trust. All profits support HHLT’s conservation and education efforts.