Look at the sky. Look at the geese. Check out the goose that flies alone.

In every gang of migrating geese, the kind that swarm through Midwestern skies this time of year, there always seems to a loner goose, the one trailing at the back of the pack, sometimes over to the side, spoiling the symmetry of the great airborne V.

And for years I've wondered: Why?

Is the laggard goose a lazy goose? Or a hardworking goose that can't keep up no matter how hard he flaps his wings?

Maybe the loner goose is shy. Or so lonely to the core that the company of other geese only reminds him of his existential separation.

I've seen these outlier geese many places, above Chicago, in the skies of Oregon and Colorado.

Is the loner goose the black sheep of the flying family?

A psychopath, perhaps, the bird that will be fingered as the perp when mysterious goose bodies turn up in some cold autumnal field, arousing the mutters: "That goose always was a loner."

Perhaps the solitary goose drops back to plot how to sneak off to the bar, or find a pit stop or grab a clandestine smoke.

I called an expert Thursday to find out, and I could tell you now what he said. But first, more of the possibilities I've entertained as I watch the geese that fly alone.

Maybe the loner goose serves as the group's caboose, a signal that this flock is over. Maybe he's like the street sweeper that follows the parade. He might be the rear guard, protecting all the birds that forge ahead.

Or maybe it's a goose whose GPS has broken, possibly a male that refuses to ask for directions.

Or maybe it's thinking, "What's the rush? Why not stop and smell the ozone?"

The loner goose might be sulking over some real or imagined offense by the other geese. It may have been sent to the back of the pack as punishment, like a misbehaving kid ordered to stand in the corner.

The question of the loner goose has nagged at me for so long that finally, in search of a reliable answer, I called Roy Domazlicky, the urban waterfowl project manager for the Illinois Department of Natural Resources.

His explanation began with the word "aerodynamics."

Geese don't like to fly alone, he said, at least not on a long migration. It's just too hard. So they travel in communes, a mix of families, singles and pairs that assemble in the nesting area up north before setting off on the southward journey.

The theory is that they fly in a V formation so that the lead goose can take the wind's force, making it easier on the others.

"Each bird behind him has progressively less drag," Domazlicky said.

But the lead bird isn't an alpha bird, he explained, it's just the one that assumes temporary wind duty, and when it gets tired, it flies to the back of the pack, where it may straggle while regaining strength.

"If you're the guy in front, you can only stay there so long," he said. "Recovery may take awhile."

In the meantime, a new bird moves in.

"They keep doing that rotation so that there's always a fresh bird in the front," he said. "They're working cooperatively to make the flight easier for all of them."

So much for my favorite theory — that the goose that flies alone is a creative, iconoclastic type who knows that the most original thought and work are cultivated in solitude, free of the honking crowd.

mschmich@tribune.com