Birds are covered in feathers
Keep the eggs somewhere warm, supervise them and make sure their covered in the warm place. <(") <- bird face
All birds are warm blooded.
Possibly you meant "How do the birds keep warm . . ."? As for why they keep themselves warm, it is to stay alive.
so that their baby's will develop properly , if your told its to keep them warm its wrong , ( birds sit on the eggs to keep them warm).
it is feathers
Birds Sit on their eggs to keep them warm, and to hide and protect them from predetors.
They have several layers of feathers and they have feet covered in feather to keep warm.
the ones that are horny
An Echidnas body is covered with hair to keep them warm
Most birds lay on their eggs to keep them warm and safe.
They keep them warm and for most of them ables them to fly.
To keep both sides warm!