The Outside Story: How loons winter

By Tiffany Soukup

When I was a child, I looked forward to spending summers with my grandmother at our family cottage on a Canadian lake. Every year, as soon as I was out of the car, we would run to the point to look and listen for loons. As an adult, I still watch loons. But it wasn’t until this past fall, when the loons began to migrate, that it occurred to me that I had no idea where they were going.

According to Eric Hanson, a conservation biologist with the Vermont Center for Ecostudies, the common loon, Gavia immer, makes its way east from our region, out into the New England coastal waters of the Atlantic Ocean. Some adults might leave their breeding lake in September, but usually to a nearby lake at this time. The bulk of adults migrate to the ocean in October, while chicks usually remain until early November. By some instinct, juveniles find their way to the ocean without the guidance of adults.

Migration is not always a one-shot flight, nor is it always a solo endeavor. Some loons flock together on lakes and fly in groups, although these flocks are often diffuse and appear unorganized. The birds fly fast, and can cover impressive distances in short periods. One was recorded making a journey of almost 670 miles in a single day.

Migration is a dangerous time for all birds, but for loons, there’s an extra danger because they may become trapped if they land in the wrong place. Loons have difficulty getting airborne. They have legs that are much farther back on their body than those of other birds. This design makes them excellent divers, allowing their legs to extend laterally like oars when kicking down. However, it also comes with a disadvantage. “Other birds such as ducks or Canadian geese are able to walk on land and thus give themselves a small running start to take off,” explained Hanson. “Loons can’t do that.”

While most other birds have light, porous bones, loons have heavy, marrow filled bones. This difference makes them excellent divers, but heavy body mass compared to wing surface area makes liftoff difficult. For all these reasons, the birds usually require about a quarter mile of water to launch into the air.

Stranded in a small pond, or taken unawares by encroaching ice on a larger lake, the birds may be doomed to a slow death by freezing or starvation. Every year there are news stories about loons getting stuck this way, and often, contentious public debates about how much risk people should take to try to catch and relocate them.

Once loons reach their winter destinations, they’re remarkably loyal to a specific patch of ocean. Jim Paruk, a senior scientist with the Biodiversity Research Institute, has observed that adult loons consistently use ocean territories of less than eight square miles for the duration of winter. It seems this fidelity to a site helps enhance their survival by helping them anticipate food sources and likely predators.

Loons in winter bear little resemblance to the iconic black and white birds we see in summer. After they complete migration, the loons transition to drab, mostly grey plumage. Because of this change, they are easy to mistake for a separate species. This is why Paruk has had conversations with veteran fishermen who swear that loons are not on their waters, in areas where the birds are in fact well established.

Loons molt in January and become temporarily flightless. This period, which lasts about two or three weeks, is stressful for the birds. Growing new feathers and keeping them well-oiled and water resistant, a grooming process called preening, requires a lot of energy. Without their wing feathers, they are also more prone to hypothermia.

As spring approaches, the loons grow restless. They make practice flights along the coast, exercising their muscles for migration. What drives them to take the risky flight back to our lakes?

The simple answer: chicks. Loons need an accessible place on a shoreline and a relatively stable water line during nesting. They seek out lakes that are large enough for takeoffs and landings, have enough fish or aquatic insects for food and clear enough water that they can see their prey. Males will return once the ice is out to stake claim to their territory, usually around April. Females tend to arrive seven to ten days after the males, and if all goes well, the pair will have two chicks by mid to late June.

As I look out to the muddy ground, I think of our loons floating out there somewhere on the big open sea. I now understand better the great risks they face in their life away from this summer home we share together. I can only hope with a bit of luck, they will return. This April, loon friends, I’ll be here and waiting for you.

Tiffany Soukup is a freelance writer and photographer who lives half the year in Vermont’s Groton State Forest and the other half adventuring abroad looking for wildlife. You can follow her findings and travels at: https://vagabondway.net. The illustration for this column was drawn by Adelaide Tyrol. The Outside Story is assigned and edited by Northern Woodlands magazine, northernwoodlands.org, and sponsored by the Wellborn Ecology Fund of New Hampshire Charitable Foundation: wellborn@nhcf.org.