[107barney]

All my dogs do this, but each one does it slightly differently.

This behavior is part of the denning instinct in dogs - they like to prepare a spot where they will rest and it is instinct to do this. Terriers (and some other breeds) are more prone to burrowing behaviors. This means the dog is preparing his den and getting ready to rest. Some dogs will gather toys and resources in their dens. My dog Barney prepares his spot each night by going down off our bed to his toys and taking his nylabones up one by one to his spot. He places them down, then he circles and digs his spot and then he lies down to rest.

It's like when we fluff up our pillows for ourselves.