Living Sanibel: Common Loon, known for diving, distinct yodel
Although a difficult bird to encounter inshore, the common loon is a frequent sighting in the Gulf of Mexico just off the islands during the winter months. In the Gulf it prefers to inhabit the coastal waters between 30 and 100 feet in depth, diving for small fish and crustaceans. When in Florida the loon does not exhibit the beautiful black and white patterns it displays up north. Its winter plumage is a dull brown on the back and neck with a whitish underbelly. In the early morning and sometimes during the evening, the wintering loon will give its distinctive cry in the Gulf, an unmistakable and unforgettable yodel.
The loon can dive up to 250 feet deep, aided by a dense bone structure found mainly on land-based birds such as the ostrich and emu. To propel itself to such depths, its hind legs are placed far back on its body, making it virtually unable to do more than waddle awkwardly on land. These two features combine to create an unusual form of loon mortality. If a loon mistakes a wet parking lot or stretch of highway for a lake, then it will not be able to take flight again and, unless rescued, will starve to death. Some birds have been forced down onto small ponds in inclement weather, and because they need long runways to take flight again, they often succumb to starvation.
The loon is also preyed upon by large sea mammals such as porpoise and sharks and along the California coast is sometimes taken by sea otters. The chicks are commonly victims of ravens, minks, snapping turtles, and northern pike.
Because it relies on small fish, the loon is also vulnerable to acid rain, which kills the phytoplankton and in turn starves out lake or pond minnows, causing a collapse in the food chain. Industrial pollutants, especially oil spills, take large numbers of loons annually. Lead poisoning from digesting lead sinkers or buckshot is another cause of mortality, as is entanglement in fishing nets and discarded fishing line.
Despite these obstacles, the common loon is not endangered. The loon is monogamous and a solitary nester. Its nests are always located just a few feet from the water’s edge.
This is an excerpt from Living Sanibel – A Nature Guide to Sanibel & Captiva Islands by Charles Sobczak. The book is available at all the Island bookstores, Baileys, Jerry’s and your favorite online sites.