I am camping in Slovenia and have found some cocoon like materials. They look like nests of some kind and are about 30cm long and 10-15 cm wide. Can anyone help me find out what these things are? Found in Tolmin, Slovenia
I think you are actually looking at dried bottle gourds, a squash relative. These are probably in the genus Lageneria. These come in an extreme variety of shapes, and have been put to many ornamental uses. They were important as containers for early cultures. Good background here and here. Search for "dried bottle gourd" images and you'll see plenty.