Have you even seen a bird that looked pale? It might be leucistic. Leucistic birds differ from albinos in that they can produce melanin but can't deposit it into their feathers, which results in muted or partial coloration.
American Robin (leucistic) Leucistic is more the technical term for what you would call an albino, being white. Or partial white. This little robin just looks like she is having a bad day. Or got into a food fight on baking day.