Audubon also is presenting a 45-minute ''Loons and Lead'' slide show at 11 rural locations between Friday and Aug. 23 to explain the natural history of loons and the threats they face from lead fishing sinkers and lures. A state law that goes into effect in January 2002 bans the sale of lead sinkers weighing a half-ounce or less. New Hampshire has enacted a similar law, and federal wildlife authorities considered a ban at some Minnesota lakes. They are highly sensitive to changes in water levels because they build their nests on the water's edge. Studies have shown they also face certain death after they inadvertently swallow lead sinkers and lead-headed fishing jigs when they ingest stones and gravel to aid in their digestion.
Loons also eat fish that have broken off anglers' fishing lines with sinkers or jigs still attached.
Once the sinkers and jigs become trapped in loons' gizzards, they are ground up in a highly acidic environment, causing almost immediate high levels of lead in their bloodstreams, according to the Audubon Society. Common loons live up to 30 years. They tend to return to the same nests each year. Maine has the largest population of loons in New England, estimated at 4,000 adults, and the state's loon population appears to have remained stable over the past decade despite threats they face. The Maine Outdoor Heritage Fund and the state Department of Inland Fisheries and Wildlife are helping to fund Audubon's loon programs.