In the wild, usually, birds fluff their feathers and spread their wings to regulate their temperature. Feathers provide insulation and are coated with an oil that promotes waterproofing. Birds fluff up their feathers in the cold so they trap as much air as possible in tiny pockets of air to hold in body heat.

What does fluffing do for birds?

Puffing up is a way for birds to conserve body warmth. You may notice that birds tend to look “fuller” on cold, winter days. Birds fluff up to trap as much air as possible in their feathers. The more air they trap, the warmer they are.

What is it called when birds fluff their feathers?

Preening is a maintenance behaviour found in birds that involves the use of the beak to position feathers, interlock feather barbules that have become separated, clean plumage, and keep ectoparasites in check. ... Birds fluff up and shake their feathers, which helps to "rezip" feather barbules that have become unhooked.