Common Loon

Quick Take

• The common loon's name has nothing to do with its calls. The real origin is far more embarrassing for the bird. Origin of the name →
• Loon chicks master one of their most impressive survival skills before they can even fly, and the timeline is surprisingly early. Chick development timeline →
• Pollution doesn't just threaten common loons. Research shows it warps their instincts in a way that traps them in a cycle they can't escape. How pollution warps instincts →
• The common loon lands on water completely differently from other ducks, and its bizarre anatomy is the reason why. How loon feet shape landings →

Though awkward on land, the common loon is a graceful hunter on the water. This mostly cold-weather waterfowl learns to dive before it learns to fly and will come back to the same nest with the same mate every year for almost a decade. The bird has found its way into a number of Native North American legends and is also the face of the Canadian one-dollar coin. Though pollution eliminated common loons in much of eastern North America, this fowl particularly thrives in Canada. Though the name “loon” comes from its goofy walk, it’s probably described better by its other English name: “Great Northern Diver.”

Incredible Common Loon Facts

• Deep diver: The common loon is a bird that can dive as much as 200 feet underwater to catch fish.
• Already famous: Canada’s one-dollar coin, called the “loonie,” features the common loon.
• Frequent-flyer: The common loon can fly for hundreds of kilometers when migrating.
• Loud and proud: Loon sounds include a distinctive “yodel” when it is claiming territory.

Evolution 

As a member of the genus Gavia, the common loon’s closest relatives are black-throated, red-throated, Pacific, and yellow-billed loons.

This family of birds is believed to date back to the Early Miocene era, approximately 20 million years ago.

During the Miocene, which occurred between 23 and 5.3 million years ago, the ancestors of the genus extended along the coasts of the Atlantic until they eventually reached the Pacific coast. This expansion would only be completed in the late part of the period. Fossil evidence of the ancestors of the genus can be found dating back to the Miocene, the Pliocene, and the Pleistocene. The Gavia brodkorbi, dating back to the Middle to Late Miocene (the Clarendonian age), discovered in California, is one such example.

Scientific Name

The scientific name for the common loon, also known as “Great Northern Diver,” is Gavia immer. ‘Gavia’ comes from the Latin term for a seabird, though its exact identity is uncertain — possibly a gull, sea mew, or sea smew — and ‘immer’ could be from the Icelandic word ‘himbrimi’ or the Swedish word for ‘dark ashes.’

Appearance and Behavior

The loon looks like many other ducks, except its bill is more pointed, like a songbird. Its feathers are mostly black, with an almost grid-like pattern of white spots across its wings and throat and a white underbelly.

Common loon sounds are well-known to people who live near their habitats. These include a distinctive yodel, a wailing sound, and a hooting noise. The common loon call is used to find a mate or declare a nesting site.

The common loon’s feet

The feet of a common loon are set further back on its body than those of other water birds. This makes common loons excellent swimmers and divers. However, the loon looks awkward whenever it walks on land. That silly-looking walk is believed to be why it earned the name “loon.” Its unique feet also make it land differently from other ducks. While most ducks land on water by skimming their feet, common loons have to skim on their belly.

Habitat

Common loons are birds that prefer colder areas close to water. In addition to Canada, loons are common in Alaska, Greenland, and Iceland, and breed rarely in Scotland. They tend to live near smaller ponds during the summer, when they nest, and migrate to larger lakes and coastal areas during the winter.

Diet

The common loon eats primarily fish. It is an expert at diving into the water to hunt. The specific fish a common loon eats depends on where it spends most of its time. For loons near coastal areas, dinner means flounder, herring, rockfish, and sea trout. Meanwhile, common loons near freshwater will eat bass, perch, pike, sunfish, and trout.

To hunt, a common loon will first poke its head under the surface of the water. Once it sees its prey, it can dive as deep as 200 feet. Smaller fish can be gulped whole, while larger fish are carried to a place where they can be eaten.

Predators and Threats

Common loons may be attacked by bald eagles. Fishing in open water also places them at risk from sharks. Other predators that pose a threat to their existence include minks, foxes, and otters. Ravens and gulls may also decide to help themselves to their eggs.

Humans stand as the biggest threat to loons, though the threat is not severe. Water pollution has caused common loons to disappear from eastern North America. However, the International Union for Conservation of Nature lists the common loon as “least concern,” meaning it is not currently at risk of disappearing.

Common loons can also risk having their eggs taken by small mammals. They may change nesting sites when this happens.

How pollution affects the common loon

Toxic water poses a threat to the common loon because the bird prefers to return to the same type of lake in which it was born. That means that a common loon hatched on a polluted lake will, according to some research, seek out a similarly polluted lake when it nests later in life. It will seek this type of lake, even if that lake has fewer fish or is worse for hatching new chicks.

Reproduction, Babies, and Lifespan

Common loons are monogamous, meaning the same male and female pair will breed together every year. Common loons live for about 20 years or more and will breed once a year for most of their lives. Each year, a common loon female will produce two chicks. This is far fewer than typical water birds produce. A female mallard duck, for example, will lay as many as 13 eggs each year.

Common loons will generally build a nest near the edge of water mostly out of sticks, reeds, and grass. They use the same nest, or nesting site, every year. The male might move the nest if eggs are lost to predators.

Common loons typically begin breeding between the ages of four and eleven, with males often starting around age six and females around age seven. They will find a mate during early summer, and the two will stake out a nesting site by circling it overhead and making a yodeling noise. The mother will typically lay two eggs. Common loon eggs will sit for almost a month before hatching, with both parents taking turns sitting on the eggs. After hatching, both mother and father feed the chicks while they are growing. It will take the chicks about 12 weeks to learn to fly, but they can swim and dive within just a few days of hatching. The male and female will migrate separately to winter quarters after the chicks have grown. The two then return to the same breeding ground at the start of each summer. 

Population

The International Union for the Conservation of Nature (IUCN) estimates as many as 640,000 common loons exist worldwide. Most of these loons are located in North America, particularly in Canada. Between 1,400 and 2,600 mature individuals are estimated to live in Europe, based on a breeding population of 700 to 1,300 pairs. While the population seemed to be growing slightly in North America, the IUCN said it was declining in Europe.