Natural selection doesn't explain why or predict that a bird might have detrimental traits such as bright coloring that can betray it to predators. Darwin invented a whole other selective mechanism to explain the appearance of such traits -- sexual selection, later elaborated into the Handicap principle. Sexually selected traits are necessarily historically contingent, but you can't just explain away any hereditary handicap as a product of sexual selection: the theory makes the nontrivial prediction that mate selection will depend on such traits.