The Lake Where You Live

We haven’t heard a loon’s call for a while unless we’ve played a video online. If you’re like me, once in a while you think about what the loons are up to in their winter territories.

In particular, I wonder what they’re eating and how they find food in places like the Gulf of Mexico and Atlantic coastal waters. How do they manage to locate prey in the vastness of the ocean?

Here in their breeding territory they benefit from a more or less captive prey base. The lakes they haunt are not that large, and it’s easy for them to locate fish around the weed beds, woody cover, rocky humps and sandbars, some of the same places that attract anglers.

Looking at its slender beak, you might think a loon would have to stick to fish with elongated profiles, like perch and young walleyes, pike, bass, suckers and minnows. But it turns out their mouths can open wide enough to also take in more ovoid species like bluegills, sunfish and crappies. 

Loons swallow their prey whole (usually while under water) and can gobble up bass as big as 10 inches, as well as panfish of a size an angler would gladly slip into an ice-filled cooler. Adult loons will eat about two pounds of fish per day, and their young ones are quite ravenous as they grow to adult size in roughly the space of a summer. 

The Cornell University “All About Birds” website says an adult loon pair and two chicks will eat about half a ton of fish in 15 weeks. They might not strictly stick to fish; they’ll also eat crayfish, frogs, and the water-dwelling immature stages of insects like dragonflies.

But what about life on the ocean? In one respect it’s easier, because the loons on migration don’t have to worry about feeding the young; they can just fend for themselves. Also on the plus side, the winter waters they inhabit tend to be extremely clear — loons hunt by sight. 

On the other hand, at sea, loons can be buffeted by rough water, and unlike ducks or gulls they can’t readily take refuge on shore. They are nearly immobile on land and so live a marine existence. 

In winter waters they eat fish like small flounder and herring, along with shrimp and other crustaceans. Although here in the north they generally hunt alone or with a mate, in winter waters they may chase prey in loose groups, or mixed in with other species like gulls and cormorants, taking advantage of schooling fish. Apparently they’ve evolved the ability to follow others and fish where the fish are.

Loons accustomed to fresh water would have a problem eating ocean creatures and ingesting the seawater if not for a special adaptation. They have special glands above the eyes the pull salt out of the bloodstream and then expel a salty solution through ducts in the beak.

So generally speaking, barring some weather or environmental calamity, the loons survive just fine in their southerly environs. Toward spring they’ll go through a molt, replacing their muted winter plumage with the striking black-and-white outfit they wear as we observe them during the breeding season.

Though it might seem hard to imagine looking out at all the snow, in roughly two months the ice will go out, and the loons will be back on our lakes again.

Ted Rulseh resides on Birch Lake in Harshaw and is an advocate for lake protection and improvement. His Lakeland Times and Northwoods River News columns are the basis for a book, “A Lakeside Companion,” published by The University of Wisconsin Press. He may be reached at [email protected].