Yum, bird poop. XD That's never happened to me, and I hope it never does! The birds were probably squawking because you came too near their nest around there (even if you didn't see one.) I was walking down my back lane the other day and I saw 2 fluffy little baby bluejays on the ground. I just had to see them so I walked up and looked at them from about 4-6 feet away. Their mom was just over head though, and she swooped down at me and almost pecked my head. She was VERY loud about it, too. XD
In the hobby for 9 years.