What's Up With The Birds?

What a mess we have here because of these birds.  What's up with them?  Last year right after we stained the deck we noticed a lot of bird poop around the pool.  I bought a bag of plastic snakes and that seemed to do the trick.  This year we noticed the same thing happening on the deck at the cabin, especially the front porch where it looked as if they were roosting on the railing.  We've also had problems with the nests, at home and the cabin, and as much as we hate to do it, some had to be removed.  My hubby even went so far as buying a big plastic owl to put on the deck to keep them away but he has to keep moving it so it continues to be effective.  So the last straw was this morning as I went out to get the paper and there was bird poop on the edge of the paper and therefore on my hand.  Yuk!!!Over the weekend I saw what looked like a swarm of birds with the end of our driveway as a target that dumped their mess.  No, I didn't actually see them in the act, but you get the picture.  Is the weather affecting them too?  Are they mad at us about something and is this an act of revenge?  Maybe it's too much of a good thing that acts like a laxative?  Don't get me wrong  -  I love the birds but no one wants to wade through poop on a deck, driveway or their morning paper.