My current suspect is... Birds(?)

If that is the big danger, perhaps I could hang up some
surplus CDs to scare them away(?)

CDs make excellent bird scarers: a string across the bed, and the CDs
hanging on another string about a foot or so long. They catch the sun as
they turn in the breeze, and birds hate it.

Good luck!

Garry


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http://pigstyave.blogspot.com/