What's up Chicago? It's Erin Allen. The holiday travel season is in full swing. And if you've ever waited in a long line at TSA, you may have had some time to look around and notice a few feathered passengers at the airport as well.

Last episode, I looked into what happens when birds get inside the terminal at O'Hare.

Today, we're going to bring you a curious city story from 2012 that investigates what happens to birds that are outside on the runway.

Here's reporter Logan Jaffe.

Chicago and Steve Brockway was leaving his job at the United Airways Reservation Center when he saw something new.

He pulled out of the parking lot at O'Hare Airport.

I saw that there was an aviary full of birds between me and the runway.

I thought that was kind of odd.

So odd, because an aviary is for raising birds, and why would O'Hare do that?

Brockway sent us his question and a photo.

That picture shows a framed wood cage about six feet by six feet with mesh wiring,

and in the cage a bunch of small black birds, maybe 20 to 30 of them.

I emailed the pick to O'Hare, then they clarify,

this aviary is actually a trap set up by the U.S. Department of Agriculture.

And the target?

The European starling.

And there's more.

After the starlings are trapped, they're euthanized, killed.

Humanely, but they're killed. In fact, last year, the USDA killed about one and a half

million starlings nationwide. Thousands were caught at airports.

We actually kind of refer to them as flying bullets.

That's Craig Pullins, a USDA wildlife biologist at O'Hare.

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