Psittaciformes

Color in feathers resists bacterial degradation: parrots
 

Feathers of parrots resist bacterial degradation due to pigments synthesized internally.

 
  "The brilliant red, orange and yellow colours of parrot feathers are the product of psittacofulvins, which are synthetic pigments known only from parrots. Recent evidence suggests that some pigments in bird feathers function not just as colour generators, but also preserve plumage integrity by increasing the resistance of feather keratin to bacterial degradation." (Burtt et al. 2010:214)
  Learn more about this functional adaptation.