On a North Woods lake in summer, loons stick out conspicuously as large, tuxedoed birds swimming about in the middle of the lake. They can be very vocal and easy to locate, as the yodeling of one loon will often elicit a chorus response from other loons in the area.
- The Common Loon swims underwater to catch fish, propelling itself with its feet. It swallows most of its prey underwater. The loon has sharp, rearward-pointing projections on the roof of its mouth and tongue that help it keep a firm hold on slippery fish.
- Loons are water birds, only going ashore to mate and incubate eggs. Their legs are placed far back on their bodies, allowing efficient swimming but only awkward movement on land.
- Loons are agile swimmers, but they move pretty fast in the air, too. Migrating loons have been clocked flying at speeds more than 70 mph.
- A hungry loon family can put away a lot of fish....
Read more here: https://www.allaboutbirds.org/guide/Common_Loon/overview