Hit the pool cover with a stick, then once they fly off, shoot them.
Speaking of which, does anyone know of a way to kill birds without waiting around all day and shooting at them? I'm considering cutting down the tree to get those motherfuckers away from the driveway. We've knocked down the nest and destroyed it. They appear to come to the tree solely for the purpose of relieving their bowels. Is there a poison or something that will kill them after they fly away? I would put some seltzer tablets there, but I don't want blood all over the car.