How Loons Fly

See how small this loon's wings are for its heavy body?

Loon wing

IMPORTANT: To learn the general principles of bird flight,
you may wish to start with our
Bird Flight Primer

Common Loon bodies are adapted for diving and fishing underwater. Feathers are very light, and flight feathers in particular are extremely buoyant. If loons had large wings, they wouldn't be able to stay submerged to chase fish. So to dive well, they have short wings and heavy bodies. Common Loons weigh about 9 pounds with a 46-inch wingspan. To put this in context, Great Blue Herons average 5.3 pounds with a 72-inch wingspan, and Sandhill Cranes weigh 10.6 pounds with a 77-inch wingspan. Those relatively small loon wings must support a lot of bird compared to the huge wings of the crane and heron!

Imagine a huge parachute floating down with a 100-pound box. It can take a long time to hit the ground. Now imagine that same box attached to a tiny parachute. It won't "float" at all but drop fast! Herons and cranes are like the box with the big parachute, and loons like the same box with a tiny parachute. Thanks to their tiny wings, loons simply can't glide or soar, but must ALWAYS flap to stay aloft.

Loon wings are so small compared to their body weight that even with strong flapping they can't support the weight of the loon in the air if they're missing a couple of feathers. Loons must work terribly hard to stay up if only one flight feather is missing. This is why loons molt all their flight feathers in winter, when they are on the ocean and can get wherever they want by swimming.

Special Challenges
  • This loon is just exercising its wings. It has to flap hard while running to actually get aloft.
    Loon stretching its wings
    The hardest challenge for loons is getting up in the air in the first place. In order to get lift, they need a lot of air rushing beneath their airfoil wings. Even running as fast as they can is usually not enough. They also need the boost of wind. So first they feel which way the wind is blowing, and then run straight into it while flapping powerfully. The stronger the wind, the shorter the "runway" they need to takeoff. Sometimes when young loons are late in developing (usually from a late nesting or when food is scarce), their flight feathers are barely ready for use when the first autumn ice is starting to form on their lake. Then without help, they are stranded. This is also why the orientation of a long, narrow lake is critical to a loon pair. If the lake runs parallel to the way the wind most normally blows, it is easy for loons to come and go. If the lake runs at right angles to the normal wind direction, it may not give the loons enough of a runway.
  • Once loons get up in the air, they are strong fliers and can cover hundreds of miles in straight flight. But migration is very energy intensive for them, because they have to flap every inch of the way.
    Also, because loons fish, they must have strong, heavy beaks and necks. They don't need to strike fish with the force that herons use, and don't have particularly long necks, so they don't pull their necks back in a crook. But they DO fly with their neck a bit below horizontal, drooping.
  • Loons have to be careful of where they come in for a landing (in their case, should we say "lake-ing"?), because they can only take off where there is a good surface of water for a runway. Sometimes loons hear frogs and see a nice shimmering surface sparkling like their favorite lake, only it's really just a wet parking lot sparkling with lights. If they don't figure this out in time, their legs and feet can be damaged by the crash landing (remember, they were expecting to land on water). And in struggling to get somewhere, they often get bad abrasions on their bellies and feet.