It’s that time of the year when lakeside residents and campers can fall asleep to the lovely and thrilling call of the common loon. Last weekend, volunteers across the state fanned out on lakes for the annual Maine Loon Count. On China Lake, counters sighted a record 21 loons during the breakneck half-hour counting period allotted to volunteers.
Maine’s population of loons — known to many as the wild voice of the northern landscape — is second in the United States only to Minnesota. An entire industry of loon paraphernalia and knickknacks has grown up around the bird; there are loon napkins, loon oven mitts, loon earrings, platters and door knockers. There are so many people who like to count loons that Maine Audubon has to turn away volunteers for the annual census.
But loons face invisible dangers belied by their healthy numbers. Of the nine places in the Northeast — from New York State to Nova Scotia — known to be “biological hotspots” where mercury levels are so high they can cause adverse health impacts in loons and other wildlife, four of them are in Maine. The mercury levels measured in loons in those four areas can cause poor reproduction and strange behavior in the birds. Biologists have said the impact of mercury on loons reminds them of the damage to birds found by Rachel Carson in Silent Spring, her landmark environmental study documenting the perilous effects of the pesticide DDT.
Where does the mercury come from? It’s carried on the wind from electric utilities in the midwest, lands on our lakes, gets into the bodies of tiny organisms in the lakes, then into fish that eat those organisms, which are then eaten by the loons, who can’t read the fish consumption advisories that are meant for us humans.
So next time you hear that mournful loon cry, think twice. We may be on target when we describe it that way.