Call of the Wild: Loons
Even before these two touched down here, I’d been learning about loons in New England. So I know that they’re mysteriously disappearing from lakes where we should expect to find them–in fact, from the very center of their celebrated recovery. Their decline has ramifications far beyond the small world of loon watchers.
In the language of wildlife biology, the common loon is an indicator species. Loons spend winters along the saltwater coast and breed on freshwater lakes, absorbing what has accumulated below them in two food chains. Their set of nesting requirements is narrow: They need clear, clean water; abundant fish stocks; and undisturbed areas in which to raise their young. They’re sensitive to industrial inputs and human activity. Their survival as a species depends on a web of healthy infrastructures–and may say something crucial about the health of the planet. I take their survival personally.
I’d wanted the pair to nest on our pond. Now I want their two eggs to hatch, the chicks to grow and fledge. I want to hear their drawn-out, parting wails as the trees turn orange and yellow, and the laughing tremolos of their return after the ice goes out next year. I want to see another nest built off the point next June. I want proof right here, outside our front door, and contrary to growing evidence, that northern lakes and coastlines remain healthy–that at least in some places we’re not fouling our own nests.
Loons are ancient birds. Near the end of the Cretaceous period, ancestral loons moved from land onto the oceans to exploit an ecological niche: Warm-blooded, they could expend more aerobic energy than the fish on which they preyed. “I pity the fish,” says evolutionary biologist James Paruk, “that first met a diving bird.”
Unlike their cousins, the penguins, loons kept the ability to fly. But they also adapted to their marine environments, and to diving for their dinners. Their bones grew nearly solid; they could expel nearly all the air from their lungs, allowing them to stay underwater for many minutes in pursuit of prey. I’ve seen loons chasing fish in shallow water and have been reminded not so much of submarines as of torpedoes.
Successful but highly specialized, loons ended up occupying a lone evolutionary limb. Roughly 50 million years ago, the five species of loons branched off from their nearest genetic relatives, a group that includes albatrosses. More recently, geologically speaking–several million years ago–retreating glaciers filled freshwater lakes across northern North America. Fish followed, and loons followed the fish. On lakes, adult loons faced few natural predators. They developed a migratory pattern that endures to this day: breeding on fresh water, wintering on the ocean, returning year after year to the same territories.
I dwell on their evolution because recent DNA sampling has revealed a striking lack of genetic diversity among common loons, suggesting that they squeezed through a genetic bottleneck around 10,000 years ago. This ancient species that has adapted so long and so well is vulnerable to a single large-scale event–and even to incremental changes in its environment.
When humans appeared on the North American continent, loons were there. Native Americans made a totem of the bird; to be called “loon-hearted” honored that person’s courage and wisdom. Native stories described mystical connections between loons and human beings. In an Ojibwa creation story, Loon was the very voice of the Creator in spirit form. Loon loved the first man and saved him from drowning, an act of generosity that allowed the human species to survive.
All but 1 percent of the world population of common loons breed in North America, most of them in Canada. They’re birds of the North American Far North.
“Far North” once extended farther south into the United States. European settlers reported loons throughout New England, down into Pennsylvania, and across the Midwest. In the mid-1800s, Henry David Thoreau studied loons on Walden Pond. He called their wails “perhaps the wildest sound that is ever heard here.” But fishermen didn’t see a mystical symbol when they saw loons–they saw competition. A family of four loons may eat 900 pounds of fish over a breeding season. A century ago, anglers arriving at Northeastern lakes routinely began their fishing trips by shooting every loon in sight.