Nest Boxes "Roosting Pouches"
For the uninitiated they are effectively a woven bag of wicker, twig and straw.
They have a hole, usually at the top and are supposed to provide a place for small
birds to rest overnight.
Check out what people have to say about them
Link below takes you to a wild about britain forum.
Roosting pouches

Gardman A02034 hive roosting pouch makes a great overnight resting places for many smaller wild bird species made from natural materials