Stiffs

I think I have figured out why dead birds keep falling on my balcony. I have never seen birds fly this low, so I think what happens is that they fly against the upstairs neighbours glass balcony walls and fall down on my balcony. I'm pretty sure if we checked, we'd find more birds around the house. Considering that they have 80 m2 terrace I'm not sure I can require them to cover it all in curtains or these plastic birds one can plaster onto the glass. What is the learning curve of birds?