feathered scare in Rosemont, IL--what's going on?

Recently I noticed some carcasses of pigeons along the Des Plaines River Road, where it runs under the I-294. Earlier last week, as I drove through the underpass, I took note of four dead pigeons beside the road. "Yikes, that's a lot of dead pigeons. I hope that's not some nasty disease..." I thought. And forgot about it.

Today, a road closure congested the Des Plaines River Road to such an extent that the traffic was barely moving. Thus, I had more than enough time to search for dead pigeons and take precise count. Morbid, yes. But I had some scientific curiosity. A few moments later, though, I reached for the window-rollup button, and quickly closed the windows. I was truly scared.

There were 16 dead pigeons, some belly-up, some crashed by cars, on only one side of the road. Sixteen. Sixteen dead pigeons in a matter ten yards (the width of the on-ramp to the express way). I couldn't see the other side of the road, blocked by the support columns in the middle, but the last time I drove on that side, there were at least three dead pigeons on that side, making it 19 in total. And that is assuming that the number hasn't increased since.

I don't know if the number of dead pigeons has actually increased over the past few days, or I couldn't see most of them when I drove there a few days ago. Either way, it is a staggering number. It is probably without doubt that something is happening to the pigeon population around that specific underpass. Whether or not it is a more wide-scale phenomenon is beyond me. But it gives me chills, the kind of vicarious chill we experience in panic movies in which a sole scientist knows that a fatal viral disease is creeping around, but cannot convince others to take action.