A Loony Visitor from the North
Updated: Dec 13, 2020
Red-throated loons AKA gavia stellata, are the smallest of the loon family. Our North American red-throated loons breed in remote coastal areas of Canada and Alaska and on small ponds in the Arctic tundra. They will occasionally overwinter on the Great Lakes, and I was lucky enough to share time with one very special loon while she visited Lake Erie during May of 2018. One night we watched the sunset together. Other times I watched her swimming and diving with the terns diving into the water around her. And on one morning, she came close enough to me that I could watch her diving into a school of shiners! This was the first time I could see what happens when the loon disappears under the water. Usually there is only the moment when the loon goes down, coming up at a totally unexpected location at some later time. But this time I could observe the beauty of the dive. And it was amazing!
Loons are specialized diving birds, completely adapted to the water. In fact, they rarely leave the water, except when nesting or while flying from one body of water to the next. Every part of the loon's anatomy was built for diving and catching fish. A loon's beak is pointed and streamlined, moving through the water with little resistance. The inside of the beak is rough, allowing a firm grip on a slippery fish. They will swallow fish whole. Smaller fish they can gulp down underwater. The large fish are brought to the surface so they can be flipped around and swallowed head-first.
They have an extra pair of eyelids which are clear enough to see through and which also protect the eyes while underwater. Built-in goggles! Loons can dive deep underwater, some as deep as 200 feet, although most dives are closer to 20 feet down (still pretty impressive!) To help keep them under the water, they have to resist floating back up to the surface. But loons have figured this out. Most bird bones are hollow, which keeps a bird light enough to fly. Loon bones are more dense and filled with marrow. These birds are also able to squeeze the air from their feathers and their internal air sacs each time they dive, making their bodies much less buoyant. A powerful force is needed to propel a large, heavy bird such as a loon under the water fast enough to catch a fish. In the loon, the feet and legs act as the propeller. The wings stay tucked into the body when diving. The fully webbed feet kick simultaneously to push the loon down during a dive. The muscles to power the feet are attached to a special extension on the leg bones that provides extra leverage to give more power. Even the positioning of the legs far back on the body makes them the perfect shape. Just like a torpedo!
And the most important part of the loon's anatomy is the part that keeps the loon dry and warm in the frigid waters... the feathers! Loons have a thick downy layer of feathers close to their body to keep them warm. They also have an amazing outer layer of feathers that will keep them completely dry! If you watch a loon for long enough, you will very likely see her preening, or fixing up her feathers. They will rub their head over their back, flap their wings, roll over on their side, and use their beak to zip the barbs on their outer feathers together. Once all the feathers are in place, water will not be able to penetrate into those insulating downy feathers, and will bead and run off the loon, just like she was never in the water.
Below is a video of the visitor from the north. I have no idea why she stayed here so long or allowed me to share some of her world, but I am so glad she did.