Now here's a story. Last Sunday I was out in the new house cleaning up for the floor to start Monday. This pair of wrens would not stay out of the house and I had to constantly shoo them out a door. Eventually I discovered they were building a nest in a hole in the drywall where a speaker control will go. I felt so bad that I had to take their hard work away but I dug out all the leaves and grass several times over a couple of days because they just kept building. Well, this morning I went out to talk to my builder who is installing quarter round and he said, oh, I had to chase a bird out of here this morning. I immediately went to the hole and sure enough this is what I found. It broke my heart for those little birds. Call me crazy, but if it were up to me, I would leave the window open until they hatched and left. DH said absolutely not.