Fluffing is a form of nesting behavior that occurs toward the end of the nesting behavior sequence.

Description

This behavior is typically unseen due to insufficient camera angles or an inability to view inside the nest. It is distinguished from unknown behavior by the enlargement of the nest from the inside. The walls of the nest appear to jump as the whole nest enlarges. It is assumed that the inside of the nest is being hollowed out by the animal pushing the walls back and up.