This video from Georgia in the USA says about itself:
Squirrels Spend Time in the Savannah Nest – Dec. 1, 2016
The Great Horned Owl nest has no birds calling it home for the time being, but that doesn’t mean it’s completely vacant. It seems that we may have a resident family of squirrels somewhere between the nest and the tree. They’d better watch out if a raptor decides to return!