Airbubbles on the underside of our awning

This will sound stupid I know, but ours was doing the same. I had never noticed them before and was a bit annoyed they had started. It looked like acid or something had caused them. Anyway a couple of days later they had gone after some rain. But then more appeared in another spot. I had a look on top of the awning and there was bird droppings where the spots were occurring underneath. I dont know if it is the acid in the droppings, but ours seem to dissapear after a few days and the awning goes back to normal. We have had some others appear and every time it is bird droppings. Then the little bubbles what ever they are dissapear on the under side of the awning as well.

Karen

Hey Guys
Thanks for your input, but we are not sure if that is the problem, we have since discovered that the biggest bubble has gone down but it has left ripples and we can see the top and under skin of the annex has seperated.. Hopefully someone can tell us what the problem might be '
Ta muchly
Mieke