“Loon Lessons”? As good a title might have been, “Everything you always wanted to know about loons but were afraid to ask.” (And yes, some of those “uncommon encounters” can be shocking.) It would be pretty hard to find a question about Gavia Immer, also known as the Great Northern Diver in Britain, that “Loon Lessons” doesn’t try to answer.

James D. Paruk has been studying loons ever since he volunteered to help a researcher friend catch (and release) them in the Upper Peninsula of Michigan, over 30 years ago. That “college buddy” was Dave Evers, whose intensive studies into loons led him to found the Biodiversity Research Institute, now based in Portland. (I have reviewed several of Evers’ books in these pages.) Paruk is now a professor of biology at St. Joseph’s College as well as an adjunct senior research scientist at BRI. His professorial background accounts for both the strongest and weakest parts of the book.

Local review

“Loon Lessons: Uncommon Encounters with the Great Northern Diver”

By James D. Paruk

University of Minnesota Press, 2021; 221 pages

$24.95

At the beginning, the book delves into to the common loon’s evolution from its earliest ancestors. The next chapters are devoted to the species’ physiological adaptation to (and by) its natural surroundings, how it swims and dives, how it courts, how it rears its chicks. As the author points out, most people get their introduction to (and are bewitched by) the loon via its famous vocalizations: the chapter “Wails, Yodels, and Tremolos” gets to the heart – or syrinx (voice box) – of the matter. Other fascinating topics include behavior, migration, threats and conservation efforts.

“Loon Lessons” reflects the author’s twin passions, research and education. Each chapter begins with an account from the field that raises the topic that will be examined in more depth in the pages ahead. Paruk has “captured and handled” over 200 loons and spent more than 5,000 hours studying their behavior (many of those hours under trying conditions given the bird’s predilection for cold, damp and mosquito-ridden haunts). In these stories, he regales the reader with interesting events, avian dramas (sometimes surprisingly violent), little personal epiphanies and reminiscences.

And then there is the story of the eternal triangle. Paruk and Evers observe a male loon returning to his natal lake with a new female. (They know this because she does not have colored bands on her leg.) The pair are busy setting up their nest when the former mate arrives on the lake. (They know this because she does have colored bands on her leg.) She does everything she can to split the pair up and rekindle the bond with her old mate.

After these tales come the scientific explanations and theories. “At my core, I am a teacher and a science educator,” writes Paruk, and he views his subject through the lenses of natural selection and behavioral ecology. In a pair of deft phrases, he calls natural selection “the parsimonious reaper of extravagance” and behavioral patterns “an optimizing agent in disguise.”

These sections of the book are packed with fascinating – and certainly to me – new scientific information. Why do loons have white bellies, red eyes, narrow hips? And why are loons so different from cormorants?

But for the average reader, the writing can be tough going. Where his notes from the field are concise and often action-oriented, Paruk’s pedagogic style tends to be awkward and confusing. The inherent chicken-and-egg element in natural selection, for example, makes clarity in discussion of it all the more important. Too often, I found the thread of his argument cumbersome and hard to follow. Contextual information sometimes amounts to overkill, with background assumptions repeated almost to the point of tautology.

I suspect these flaws may be due to Paruk’s trying to adapt lecture notes to the book format. I can imagine him giving a marvelous, animated lecture to his students, dashing up to the blackboard to underline this or that point. The lessons in “Loon Lessons” certainly read like that. And as such they are terrific. In turning them into a book, however, a stronger editor’s hand could have helped streamline the text and make it more comprehensible. It might also have caught occasional slip-ups, such as writing descendant instead of forebear, or razorback instead of razorbill.

However, this criticism should not deter anyone who is interested in loons. “Loon Lessons” is an elegantly produced book, and for loon lovers it is a must-have. In the end, Paruk is quite optimistic about the common loon’s future. Besides adding to our knowledge about these ancient birds, “Loon Lessons” explains why. “People love their loons,” he concludes, “and will go to great lengths to make sure they grace our lakes each year.”

Thomas Urquhart is the former executive director of Maine Audubon, and the author of recently published “Up for Grabs, Timber Pirates, Lumber Barons and the Battles Over Maine’s Public Lands.”