The insulation is provided in layers, under the skin is a thick layer of blubber, then there is a layer of downy feathers that trap air, and finally another layer of waterproof feathers that keep the cold water away from the skin.
(downy feathers; trap; air) (waterproof feathers; keep; the cold water; away from the skin)
downy feathers waterproof feathers
trap keep
air
the cold water away from the skin