It has appeared two days in a row on my balcony, at exactly the same place. There's nothing near that can give me a hint of what it is. The birds can access the place easily. It's an inch in size, it's dry. In the photography you can see a eyelash and some hair, because has been taken after sweeping.
The place is Jerez de la Frontera (Cadiz, Spain).
What it could be? I'm curious and I would like to know why it appears.