This reminds me of a couple years ago when I could hear squeaking. First I thought it was my PC, then the water pipes but it was neither. Sometime later when I needed to go upstairs and having to pass the open door leading to the conservatory, something shot past and when I looked in I saw a bird and thought 'must get you out before you hurt yourself' when I caught sight of another one banging into the windows trying to get out. Double trouble and after a lot of coaxing I managed to get them out of the door. They immediately shot into the nearest tree and gave me what I thought was a lot of verbal but thinking about it they were probably saying thank you. They must have got in one of the small windows. I am used to rescuing bees and things but never birds. sheila x