Why Can't Loons Walk on Land? Legs Built for Diving

Legs placed for swimming, not walking

In most birds, the legs sit near the middle of the body, under the center of gravity, so the bird can stand and walk comfortably. In the common loon, the legs are set far back toward the tail, and much of the upper leg is buried inside the body. Only the lower legs and large webbed feet stick out.

Underwater this design is ideal. The feet work like a ship’s propeller at the stern, pushing the bird forward with strong, sweeping kicks, while the streamlined body glides ahead. The leg bones are flattened from side to side, which reduces drag as they move through the water, and the hip muscles are very powerful.

On land the same arrangement is a disaster. With the feet so far back, the bird’s weight falls in front of them, and it tips forward. A loon trying to walk usually ends up pushing itself along on its breast, using its feet like oars, or lurching forward a step or two at a time before flopping down again.

Built for diving: solid bones and heavy bodies

The loon’s whole body is designed for diving. Unlike most flying birds, which have hollow, air-filled bones to save weight, loons have many solid bones. The extra weight helps them sink and stay underwater with little effort. Loons can also squeeze air out of their feathers and air sacs to sink lower in the water.

This makes loons excellent underwater hunters. They usually dive 4–10 m (13–33 ft) to chase fish, and they have been recorded as deep as about 60–70 m (200–230 ft). But the same heavy body that helps them dive also makes them poor at walking and hard to get into the air.

Why do loons nest at the water’s edge?

Because loons move so badly on land, they come ashore for very little except mating and nesting. Even then, they go no farther than they must. A loon nest is usually built right at the water’s edge, often on a small island, a muskrat lodge, a floating bog mat or a sheltered marshy shore.

The nest is a mound of mud, grasses and water plants, sometimes with a short “slide” worn into the bank where the bird goes in and out. If a predator or person approaches, the incubating loon slips straight into the water and dives, rather than trying to walk away.

This habit has a downside. Nests just above the waterline can be flooded by rising water after rain or by dam releases, or stranded high and dry when water levels drop. Boat wakes can also wash over nests. In many lakes, conservation groups provide floating nest platforms that rise and fall with the water to help loons nest safely.

Why do loons need a long runway to take off?

Loons are heavy birds with relatively small wings for their weight. Biologists call this a high wing loading. It means a loon needs a lot of speed before its wings can lift it.

To take off, a loon faces into the wind and runs across the surface, flapping hard and slapping the water with its feet, until it builds enough speed to get airborne. In calm air this can take a long stretch of open water. That is why loons need lakes big enough to act as runways, and why they are rarely found on small ponds surrounded by trees.

Once airborne, though, loons are strong, fast fliers. They fly with rapid, steady wingbeats and can reach about 120 km/h (75 mph) during migration.

Landing is equally unusual. Instead of braking with their feet like ducks and geese, loons glide down and skid along the water on their bellies until they slow down.

Loons stranded on land

Because they cannot take off from the ground, a loon that lands in the wrong place is in trouble. During migration and storms, loons sometimes mistake wet roads, parking lots or shiny wet fields for water and come down on them. Once on land, they cannot get back into the air and are stranded.

If you find a stranded loon, the right step is to call a local wildlife agency or a licensed wildlife rehabilitator and keep people and pets away. Loons have sharp, dagger-like bills and can defend themselves strongly.

Are loons the only birds that can’t walk well?

No. Several other diving birds have legs set far back and walk awkwardly, for the same reason. Grebes, which dive for fish in lakes, are also clumsy on land and nest on floating platforms. Penguins have legs placed far back too, but they evolved an upright posture that lets them waddle, hop and toboggan on their bellies, as explained in do penguins have knees?.

Loons simply took the trade-off further than most birds: they gave up almost all ability to move on land in exchange for being among the best divers in the bird world.