ferryman

I had a bird nesting box situated in a tree in my garden it has a small hole in it just big enough for blue tits or the like to nest in it. After the cat next door and the squirrels had ravaged the box and killed the mature birds I decided to relocate the box to what I thought was a safe place, so I placed the box 3/4 of the way up the side of my house where I thought nothing could get at it. I watched and listened for a few weeks the blue tits making their nest, then my wife spotted some of the nest on one of her hanging baskets and on further inspection found a small egg in another one.
Has anybody any idea what bird or other animal has done this to the nest.

p.s. the hole is much to small for a cuckoo to get in.

Cheers

hurricane

Squirells are more than capable of climbing verticle walls.