WHEN Jeff Wells, vice president for boreal conservation at the Audubon Society, first encountered the call of the common loon on a pond near Mt. Vernon, Maine — about an hour and a half north of Portland — he thought he may have heard a ghoul. “I leaped out of bed and ran into my parents’ bedroom, like, ‘What is that?’” he told Grist, describing a melancholy wail that has made loons famous far beyond the birding community.