Why Are Loons Still Dying from Lead Poisoning?

In 1987, wildlife veterinarian Mark Pokras was in his office at Tufts University in Massachusetts when a colleague from New Hampshire called. “I’ve got a dead loon here,” she said. “If I bring it down to you, can you tell me how it died?”

Understanding what’s killing wild animals is often the first step to saving them, and over the course of his career, Pokras has necropsied everything from whales to hummingbirds. Yet this was his first loon—in part because common loons (Gavia immer) had only recently begun repopulating New England after being nearly extirpated by 300 years of hunting, pollution, and habitat loss. European settlers so disliked these “ill-shap’d” birds that nature writer Henry David Thoreau described his neighbors on Walden Pond in Massachusetts shooting them just for fun. By the early 1900s, common loons—which winter on the coast and spend summers nesting along inland lakes—had disappeared from their breeding grounds in Massachusetts and much of New Hampshire, and been reduced to a fraction of their former abundance elsewhere in New England. Places with names like Loon Pond didn’t see nesting loons for more than a century.

With the banning of DDT and passage of the U.S. Clean Water Act in the 1970s, however, loons began returning to the region, and people came to see them as symbols of a recovering wildness. The birds’ red eyes and geometrically patterned black-and-white plumage are instantly recognizable, but loons are most beloved for their long, tremulous vocalizations. In the same way that a train whistle symbolizes the freedom and loneliness of travel, loon calls have come to represent a specific, nostalgic kind of northern wilderness: piney woods, the clean smell of a lake, perhaps a rustic cabin tucked away on shore. Flannel shirts, bug spray, an early morning fishing trip. Scientists say that smell is the sense most strongly connected to memory, but for people with a connection to such lakes, there’s nothing like the sound of a loon to conjure an entire place, an entire feeling. Some locals can identify individual birds by the sound of their voices.