Book excerpt: The nature of the common loon, from biology to behavior, from one of the world’s foremost observers of the revered waterbird Even those who know the loon’s call might not recognize it as a tremolo, yodel, or wail, and may not understand what each call means, how it’s made, and why. And those who marvel at the loon’s diving prowess might wonder why this bird has such skill, or where loons go when they must leave northern lakes in winter. For these and so many other mysteries, Loon Lessons provides evolutionary and ecological explanations that are curious and compelling. Written by one of the world’s foremost experts on the subject, the book is a compendium of knowledge about the common loon and an engaging record of scientific sleuthing, documenting more than twenty-five years of research into the great northern diver. James D. Paruk has observed and compared loons from Washington and Saskatchewan to the coasts of California and Louisiana, from high elevation deserts in Nevada to mountain lakes in Maine. Drawing on his extensive experience, a wealth of data, and well-established scientific principles, he considers every aspect of the loon, from its plumage and anatomy to its breeding, migration, and wintering strategies. Here, in the first detailed scientific account of the common loon in more than thirty years, Paruk describes its biology in an accessible and entertaining style that affords a deeper understanding of this beautiful and mysterious bird’s natural history and annual life cycle.