The wall by the terrace is glass. It is mirror from the outside and lightly tinted see-through from the inside. I thought it is unlikely that the bird hit the mirror because it should have seen itself colliding with "another bird". Also, the wound is on the back and not on its face or chest which could have hit the wall first.

Your field of study is amusing. This is my first time to know of such course. I just knew of plain forestry. I was born and grew up in a mountainous region so I can imagine your role and how fun it is to be leading the children to know more about nature. 😊

Have a great week ahead!