No didn't read it in the National Enquirer,

but a local newspaper. Anyway, they said that it's possible that bird poop destroyed the bridge in Minnesota. That's right, bird poop might have been the culprit behind the I-35 bridge (over the Mississippi River) collapse.
The culprit: pigeons.
A few years ago, I would have laughed my head off, and chalked it up to the theory that dinosaurs became extinct because they farted themselves to death... whew, that methane...
But this is not a few years ago. This is now. My roofing shingles on my home are apparently very warm and cozy little homes to pigeons. So I've learned the real truth about these birds: Pigeons may be cute (to some) to look at but they are disgusting, dirty birds. Their poop is toxic. It eats through cement, roofing materials, car paint, etc. Wait - it gets better:
Pigeon poop becomes acidic when water is introduced to it.
Nice.
So if you think rain is going to wash away your pigeon poop, well you may be right - and it'll take bits of the cement/roof/paint etc with it! I found out the homeowner's insurance doesn't cover any damage done by pigeons. Don't you love learning things by personal experience?
Now I'm waiting for someone to do a sequal of Hitchcock's The Birds. It'd be a science fiction one... a small rural town, suffering from a drought, covered in pigeon poop. And then the first rain comes...