Dan's Feathursday Feature: Common Loon

Back in a former life, when I studied logic, I was taught to beware of sneaky arguments known as syllogistic fallacies. Here’s an example:

All birds have feathers
The Common Loon has feathers
Therefore, the Common Loon is a bird

It ain’t necessarily so. The third statement does not necessarily follow from the first two, because even if it’s true that all birds have feathers, it’s also possible that some creatures that are not birds could have feathers, too. Right?

Well, it’s possible logically, but not biologically—at least not on this planet. Feathers are a very special body covering invented by birds, for birds, and only for birds. This is one of science’s rare categorical statements: If it has feathers, it’s a bird; if it’s a bird, it has feathers. No exceptions.

Usually when we think of feathers we think of flight. After all, it was the development of feathers that gave birds the leg up, so to speak, in the evolutionary race for the skies. We know, of course, that there are a few birds that cannot fly, like the ostrich and the penguins. But those are exceptions that prove the rule. The feather is a super-light, super-strong body covering that serves at one and the same time as insulation, decoration, protection and, usually, air-born propulsion.

But there are feathers and there are feathers, and it was the Common Loon that opened my eyes to the amazing variety, ingenuity and even audacity with which every species uses and modifies feathers to serve their particular needs and lifestyle.

My wife and I have a love affair with loons that is almost as long as our own—ever since hearing their hauntingly beautiful wail while camping in Minnesota’s Boundary Waters on our first anniversary. Many years later, nearing anniversary number twenty-something, we were at Seney National Wildlife Refuge in Michigan’s upper peninsula, where we had just spent an exciting hour watching several loons diving and sharing their catch (photos). It wasn’t until much later that I learned that Seney NWR is home to the oldest documented pair of Common Loons in the world. The male, known as ABJ (Adult Banded Juvenile), was banded at Seney NWR as a young chick in 1987. The female, known as Fe, is at least a year older. Since 1997 they have been meeting up and nesting every spring at Seney, and 2020 marked their twenty-fourth successful brood!

Inspired by this amazing pair, I read everything I could find about loons. I learned that loons are intrepid divers, who have eschewed the hollow bones of most other birds, because air-filled bones inhibit their diving. I learned that, maybe because of their relatively heavier bones, loons require as much as a quarter mile of open water runway for taking off. Once they’re air-born, though, they are fast fliers, able to cruise at 70mph.

Among all that I learned about loons, one factoid struck me more than all the others: When at its wintering grounds in the southern USA and coastal areas of North America, the Common Loon loses all its wing feathers and is unable to fly for a two to three-week period. Molting is part of every bird’s annual biological rhythm, of course, but other birds lose and replace feathers more strategically. It struck me as totally loony that a bird would endanger itself by losing its ability to fly—the very thing that sets it above the flightless riff-raff.

But if you’ve ever tried to keep track of the whereabouts of a loon when it’s in a diving mood, you soon realize that flight is not its strong suit. It’s most at home on and under the water. So when it comes to replacing worn feathers, it’s almost as if the Common Loon looked at all those other birds molting feathers slowly, and decided—evolutionarily speaking—to just drop and re-grow all its flight feathers at once and be done with the whole molting mess in one fell swoop. “Can’t fly? So what. My wings did their job getting me here. I plan to be here for the next several months, nowhere special to go. Catch me if you can.”

It was a eureka moment for me, to realize that it is best to think of the Common Loon as a water creature that can fly, more so than a flying creature that swims. Penguins only wish they had thought of it first.

I have since learned that loons are far from the only waterfowl that perform the “don’t-need-flight-feathers” trick; many others do the same. But it was the Common Loon that opened my eyes to this magic, so please forgive me if I give the loon all the credit.

I could go on and on about the incredible Common Loon, but let me close with a valid syllogism that sums it all up:

All birds are amazing
The Common Loon is a bird
Thus, the Common Loon is amazing

 It’s only logical.

Dan's Feathursday Feature is a regular contribution to the COS blog featuring the thoughts, insights and pictures of Chicago birder, Dan Lory on birds of the Chicago region.