We have one of those cheap sheet metal sculptures outside a window. These little guys come back every spring. They're about two inches long and build/refurbish a nest inside the sculpture and are currently at work. Don't know what kind they are, but they're noisy little things. Their chicks are too when they're being raised and the parents are flying back and forth getting them food. We never see the chicks. I don't know how the parents train them to fly.
