We've had accidents here, but thankfully nothing related to the feeders. It's kind of nuts... how often we do one thing to help one bird and it hurts or aggravates another.
A funny... last year we parked our vehicles outside of the garage in hopes the Barn Swallows would move in. The cars gave Mrs. Cardinal the nerves. She found her reflection in the side mirrors and proceeded to beat up on herself. The cars went back into the garage. No Swallows last year, but a pair moved into the garage, cars and all this year. We just made sure not to run the vehicles, mower in there for long.
A not so funny... We had built two Chimney Swift towers with an attached garage. We're still waiting for the Swifts to move in. Well, a pair of Wood Ducks came over to look for a nesting spot... you might know where this is going. ( I blame habitat loss, if anything.) The female ended up going in and falling to the bottom. One of my children tore off the air vent and she flew out. I suspect it was adrenaline. She and her mate flew off, but then a few minutes later, he flew in another direction by himself. If she was injured and couldn't fly at all, we could have taken her right to a rehabilitator who is just 9 miles away, but in this case we couldn't do anything.
We've thought about putting up a Wood Duck box, but really can't. 1. We're active here and they are afraid of people. Being hunted would do that to a species. 2. We live on a gravel road, but even so, there are crazy drivers out here. Mom and babes would have to walk across the road to get to the creek. I do not feel right about exposing them to a possible smashing.