The Lake Where You Live

It’s hard to avoid learning about loons; so many articles are written about them, so many pictures shown, videos created, websites posted. But if you really want to take a deep dive into loon knowledge, I have the place for you.

It’s a book called “Loon Lessons: Uncommon encounters with the great northern diver,” written by James Paruk and published by the University of Minnesota Press. Paruk is one of the world’s leading authorities on loons and has studied then for almost 30 years. He’s a professor of biology at St. Joseph’s College of Maine.

I learned from this book that there are five species of loons. Our common loon is the only one that breeds in any of the contiguous 48 states. The others nest on lakes in the Arctic tundra. Paruk describes all five species, including red-throated, Pacific, Arctic and yellow-billed, but devotes by far the most attention to the one whose calls are a signature of the Northwoods.

Paruk offers insights to how loons are built and why. I learned, for example, that the common loon’s white breast functions as a kind of camouflage. This quality, known as countershading, makes loons on the surface difficult for predators to see from below. 

That might not matter during the breeding season on the lakes here in the northern states and across the Canadian provinces, but it can make a great deal of difference during the three to four months after migration when they live on the open ocean. 

Loons are uniquely built for diving, which is how they seek out and capture food. The skull is thick and heavy, and many of the bones are solid, not hollow as in most birds. “If you are attempting to get to the bottom of a lake to forage for food,” Paruk writes, “it helps to get these faster so you can spend more time searching and pursuing prey. Added weight is a good thing…”

Streamlining is another quality: “It is observable in literally every part of their anatomy, from their skull, to the shoulders and hips, to their legs and feet.”

Paruk devotes considerable space to analyzing the loon’s calls — the wail, tremolo and yodel — and the roles they play in communication.

I learned about various trade-offs involved in adults raising chicks. Finding and delivering food to the young is a constant responsibility. Paruk describes a day on the Turtle-Flambeau Flowage on which he saw a pair of loons deliver 184 prey items to their two chicks. The male and female divide that duty almost equally, and in the bargain they need to catch enough fish to feed themselves.

And then I learned why is it that sometimes here on Birch Lake I have seen as many as six loons swimming together, but only briefly before they take off and go their separate ways, Events like this are common and are called social gatherings. Researchers theorize that these meetings are preludes to flocking for fall migration, or opportunities for loons to gather information about the availability of a mate or a territory. 

There’s much more to learn from this book, and while it’s a deep dive into loon science, it’s also written in a style easily accessible to the average reader. 

Ted Rulseh is a writer, author and lake advocate who lives on Birch Lake in Oneida County. His new book, “Ripple Effects,” has been released by UW Press. You can learn about it by visiting his website at https://thelakeguy.net.