The Great Northern Loon, or Common Loon, is a large duck-like, diving bird that rests on the Chesapeake in late Fall and early Spring. You will most likely hear the loon before you see it. It is this distinctive vocalization, a quivering “ha-ou-ou,” that makes the bird so identifiable from a distance. At twilight, the call of the loon is both sweet and slightly mournful.

Not only is the Loon’s song distinctive, its coloration is quite beautiful and unique as well. In winter the Great Northern Loon’s plumage is black above and white below with a gray bill. It has a white throat. During breeding season its plumage changes to a distinctive black and white checkered back and neck.

Loons grow to be about 2 to 3 feet in length, with a wing span of up to 5 feet. In flight, they have a slightly hunchbacked appearance with their large feet trailing behind.

Loons do not breed in the Bay watershed. They breed in the Great Lakes region of the US and in Canada, Greenland and Alaska. They are ground nesting birds found at the edge of woodland lakes and ponds, often on islands for protection. The name “loon” presumably stems from the ungainly, clumsy manner of their walking on land. It’s clumsiness on land is due to the legs being positioned farther back on their body than other sea birds. While not well-suited for walking, it’s ideal for diving. Landing on water is also different from other birds. They land on their bellies to slow down, rather than on their feet which are positioned too far back. And when taking off, they need a running start and a long runway.

Great Northern Loons are not clumsy in the water however. The loon is a diving bird. It swims calmly along the surface of the water and then suddenly plunges below, as deep as 200 feet, for its prey of small to medium size fish.

The loons begin arriving in the Chesapeake in late September after migrating from their northern breeding grounds. By the end of October, loons are found by the thousands on the Bay’s open waters and in its rivers. After fattening up, they depart in December, continuing their southward migration to the outer banks of North Carolina.

By late February through March, they are back, this time wearing their distinctive breeding plumage. After a few weeks, they head north to build nests.

According to the crusty old fishermen down here on the Chesapeake Bay, an excess of Loon calls means “rain is a comin’ for sure.”

For more articles on the Chesapeake Bay by this author, see:  The Chesapeake ,  The Bottlenose Dolphin , Buffelhead ,  Sea Nettle , Barnacle ,  Blue Crab ,  Oyster , Eagle ,  Great Blue Heron ,  Osprey

© 2010 Consumer Guide by David Sullivan