They’re Only Human

Jim Paruk, a biologist who has studied loons for even longer than I have, has just published a book on loons and his work. Loon Lessons is quite a good book, in my opinion. Jim is a self-effacing fellow, and he writes in a pleasant, matter-of-fact, humorous style that reflects his personality. He has also learned a great deal about loons. The knowledge he has gathered over the years — and in the run-up to his writing of the book, I suppose — has resulted in a solid, informative compendium about the species that long ago became the focus of my own research. His chapters on loon anatomy and diving, loon evolution, and human impacts, in particular, are authoritative, thought-provoking contributions to the loon literature.

Jim uses a simple but compelling tool throughout the book: adaptationism. That is, he presumes that the process of natural selection has guided the evolution of loons, as in all species. His task then becomes to learn how each aspect of the bird’s anatomy, ecology, and behavior has abetted its survival and reproductive success. He guides the reader through example after example by this formula. The result, fortunately, is entertaining, effective, and convincing.

Like any successful piece of writing, Jim’s book leaves you thinking in new ways. For example, he spends a good deal of time discussing loons’ bright, conspicuous breeding plumage and seeking to understand how the striking black and white pattern might aid loons in surviving or breeding successfully. I will not steal his thunder by sharing the conclusion, but he makes a good case. And, as a scientist, I believe that Jim’s hypothesis about loon coloration is testable, at least to a degree.

Jim’s unrelenting focus on the adaptive value of loon traits breaks down a bit when he comes to “social gatherings” — the summer aggregations of four or more adults that seem to swim peacefully together across a lake surface for a half hour or more. (Sarah Dibbet’s photo at top shows a social gathering that she observed today in our Wisconsin study area.) Our study area is unique in that relentless banding of chicks has yielded a large population of young floaters aged two to seven years that are major participants in social gatherings. Analyzing the behavior of these floaters statistically has shown us that they seek to find territories with chicks so that they can return the following year to evict a pair member and take its place as a breeder. Naturally, parents of chicks seek to hide them from floaters to keep the chicks alive and also prevent floaters from learning the value of the territory in one year and evicting them the next. This high stakes game of hide and seek is the fulcrum on which social gatherings rest.

Lacking a large population of marked young floaters to observe, Jim, like earlier loon biologists, falls back upon speculation to explain social gatherings. Judy McIntyre, whose 1988 book, The Common Loon, inspired Jim and me to begin studying loons but who worked with unmarked individuals, interpreted social gatherings as efforts of loons “to reinforce cooperation among adults.” Loon Lessons takes its cue from McIntyre, stating: “Social gatherings likely foster cooperation among potential flock members”. (To be fair, Jim acknowledges that an additional reason for social gatherings might be “to gather information about the availability of a mate or a territory”.) Thus, both authors suggest that loons attend these get-togethers chiefly to prepare for feeding together in fall pre-migratory flocks. This is pure speculation, by the way; no loon biologist has identified participants in social gatherings and followed up to see if these same individuals forage jointly, months later, in pre-migratory flocks.

How could two distinguished, knowledgable loon biologists struggle to understand one of the most familiar and conspicuous loon behavior patterns? As I have implied, the main reason is simple: lack of marked floaters. Floaters are major players in social gatherings; fifty-five percent of the adults that Jim observed during his study of social gatherings were unmarked. The second reason why many of us who love loons (I place myself in this group) are often unable to come to grips with some aspects of their social behavior is that we love them too much. We place loons on a pedestal. We wish them not to be cold and calculating but better than ourselves. But they’re not.