I once has a duck knock off [as in hit,not knicked] the mirror on my BMW motorcycle once
If bird hits building, 90degree impact. Whereas Astra, depends on shape and clenliness, has a bit, only a bit of aerodynamics going for it. Ergo, pigeon didn't hit the Asrta it hit the airflow. So any bird marks are in, sorry, on the back. I knew you had it bakcwrads