All birds will do this to keep warm.
When they puff their feathers out, air gets "trapped" within the feathers and warmed up by the birds body heat. It's like a home-made blanket.
If your bird is doing this regularly, make sure their cage is nowhere near a draft or a window which is constantly open, but also make sure they are not in direct sunlight, as extensive heat exposure will kill a bird.
You can also invest in a hanging bird bed. This is basically a tunnel made of fabric which is placed in their cage, the bird sits inside it to sleep while keeping warm at the same time.
Yes they can survive in cold weather.
they are specials in cold and hot weather.
you actually have to have your house very warm. They won't survive in cold weather they will die if there in cold weather well some insects can't survive in cold weather.
It is not normal for them to live through cold weather, but on some counts they do.
they live in cold places
Bird's feathers act as insulators against the cold. They often survive cold weather by finding a protected area out of the cold weather.
that makes no sense
No, gnats do not cold air at all. Gnats do not survive the cold weather. They like hot and humid weather.
there fur
It depends which kind of fungi.
Yes, try can withstand hot or cold weather.
No. It's too cold there and there is no food chain for finches.