If you know birds, you know that preening isn’t cosmetic fluff. It’s a meticulous cleaning and placement of the bird’s survival gear: feathers. Feathers need to be pristine for flight and for insulation. During oil spills, the analogy used about feathers is that a spot of oil on a bird’s plumage is like a hole in a wetsuit. A substance like oil breaks the seal of the perfectly hooked barbules of the feather, making it impossible for a bird to insulate and thermoregulate. Any compromise in plumage integrity can lead to dire consequences for birds. So, preening truly is a manifestation of existence for feathered beings.
A short primer on feather anatomy: The Wonder of Bird Feathers