Saying that, we had a bizarre incident like that a few months ago. The border to one side of us is made up by the neighbour's house - it extends back a long way from the road to partway along our garden. No windows anywhere on the side facing us. I was outside and a pigeon flew from the opposite side and smack into the midde of this 3-storey wall as if would normally fly through there unrestricted, and it seemed to be going full pelt. Needless to say it broke its neck and I was quite perplexed. It also landed right where we had just built our raised bed the day before and having dug up some bones and teeth (which we had to have checked by the police to ensure they weren't human), I was starting to think we had invoked a curse or something!