How is a bird with fluffed up feathers like a person with goose bumps?

A bird with fluffed up feathers often does so to trap more air for insulation, providing warmth and comfort, similar to how a person gets goosebumps when they are cold or frightened. In both cases, the physical response serves as a way to regulate body temperature or create a protective barrier. Fluffed feathers can also make a bird appear larger to potential threats, akin to how goosebumps can be a response to fear. Thus, both phenomena reflect instinctual reactions to environmental changes or emotional states.