Bird Exam 2: Color

Biochrome pigments

• chemical compounds that absorb energy of light and reflect other light

• this produces the observed color

melanins

• produced metabolically, strengthen feather tips

• eumelanin

  • brown

  • black

  • dark gray

• phaeomelanin

  • tans

  • rusts

  • some yellows

carotenoids

• obtained from diet

  • reliable source of reproductive fitness

• xanthophylls

  • oxygen in chemical formula

  • bright yellow

  • reds

  • oranges

• carotenoids

  • oxygen not in chemical formula

  • subdued yellow

  • reds

  • oranges 

porphyrins

• produced metabolically

• typical porphyrins

  • reds

  • browns

• specialized porphyrins

  • turacin

    • cherry

  • turacoverdin

    • green

    • turacos

      • only green birds

    • associated with copper intake

structural color

• physical alteration of the components of indecent light on feather surface, a result of tissue learning and eagles characteristic of barb structure

• a prism effect is created by the cell structure of the barbs

• combines with the actual color to make the color we see

structural color: blue

• red and yellow are absorbed by the surface cells

• dark melanin backing

structural color: green

• blue structural color + melanin backing + yellow pigment

structural color: iridescence

• angle of incidence

  • air filled oval pallet stacked evenly and separated by layers of keratin cause light wave to bounce off surfaces at different distances from source

  • waves reflect back from surfaces in phase, out of phase, or opposed depending on movement of organism and subsequent angle of the incident light

  • angle is influenced by position of the organism and in the base of birds by angles built into the feather structure

angle of incidence

• in phase

  • high intensity

• out of phase

  • low intensity

• opposed

  • black

structural color: UV light

• birds can see into the UV spectrum