Which behavior indicates a comfortable state for a bird?

The behavior that indicates a comfortable state for a bird is rousing. Rousing is when a bird fluffs its feathers, which serves several purposes, including regulating body temperature and maintaining feather condition. This behavior often occurs when a bird is relaxed and at ease, allowing them to settle into their environment. During this time, the bird may also stretch its wings and legs, further demonstrating that it is comfortable in its surroundings.

Gorging refers to overfeeding or consuming excessive amounts of food, which does not necessarily indicate comfort but rather an abundance of food or potential stress from food availability. Hacking involves the practice of allowing young birds to leave the nest and explore, which can signify developmental progress but does not directly relate to their comfort level. Rangle is not a standard term associated with bird behavior in this context, thus lacking relevance to indicating comfort in birds.