..a wasp's nest

This extremely fragile wasp nest was built inside a bird box, and attached to the underside of the roof by the little projection just visible on the bottom left of the photograph below.

This nest was not made by the common wasp, which is far too large, but by one of the many smaller varieties of wasp.

There are said to be as many as 9000 different species in the UK, though there are only a small number of paper wasps, as in this example. Wasps that make a paper nest can often be seen scraping pieces of wood at nest-building time.