Threats

• Habitat destruction is the largest threat to common loon populations. Shore line development destroys nesting areas for loons, which in turn stops them from reproducing. Even creating recreational areas nearby can have drastic effects. For example, allowing dogs in the area of a loon nest may cause the loon to abandon the nest, or may lead to the destruction of eggs.
• Boating is a problem because loons are very picky about their nesting sites. They will not nest on a lake that is too noisy with boat traffic. Even canoes and small fishing boats can create problems. If a fishing boat for example is too close to the nest for an extended period of time, a mother loon may flee from the nest. Without the mother loon to incubate the egg, it will get too cold and die. In rare cases, people intentionally harass loons. They chase them down in boats, disturbing their feeding patterns, and separating them from their youth, which can cause the youth to fall to predation or exposure.
• Fishing line, fish hooks, and lead sinkers also kill loons. Loons can die from internal injuries after consuming hooks, or die after being entangled in fishing line. Also, loons have been known to swallow lead sinkers, mistaking them for the pebbles they use to grind food in their gizzards. After swallowing them, they die of lead poisoning.
• Water pollution also poses a problem to the common loon. Chemicals that are dumped into bodies of water cause plants to grow excessively. This excessive plant matter clouds the water, and makes it difficult for loons to catch fish. A loon will not nest on a lake if it can not catch fish on that lake.