Feather Color I • Pigments can be in the keratin – Melanins: black to light tan or grey – Carotenoids; red, orange, yellow, blue, green – Porphyrins: red (magenta), brown, green • Birds can manufacture melanins, but must obtain carotenoids in the diet. – Roseate spoonbills and pink flamingos need crustaceans (e.g. shrimp) for their color
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Feather Color I Pigments can be in the keratin – Melanins: black to light tan or grey – Carotenoids; red, orange, yellow, blue, green – Porphyrins: red.
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Feather Color I
• Pigments can be in the keratin– Melanins: black to light tan or grey– Carotenoids; red, orange, yellow, blue, green– Porphyrins: red (magenta), brown, green
• Birds can manufacture melanins, but must obtain carotenoids in the diet. – Roseate spoonbills and pink flamingos need
• Ultraviolet structural colors can be produced by two types of structures.
• Primarily iridescent colors are produced by arrays of melanin granules in feather barbules. – Those structural colors are created by coherent scattering,
or constructive interference, of light waves scattered from the layers of melanin granules in barbules.
– A few hummingbirds and European Starlings are known to produce UV hues with coherently scattering melanin arrays in feather barbules.
Ultraviolet Colors II• The most commonly distributed UV hues, however, are structural
colors produced by light scattering from the spongy medullary layer of feather barbs. – primarily UV hues have been documented in Chalcopsitta cockatoos
(Psittacidae) and Myiophonus thrushes (Turdidae). – Extensively UV hues with a peak reflectance in the human-visible blue
range have been observed in feather barbs of Blue Tits (Parus caeruleus), Bluethroats (Luscinia svecica), and Blue Grosbeak
– Prum et al. (2003) have found extensive UV reflectance from apparently blue feather barbs in many families and orders of birds including motmots (Momotidae), manakins (Pipridae), cotingas (Cotingidae), fairy wrens (Maluridae), bluebirds (Sialia), buntings and others.
• The structural UV hues of feather barbs, like other barb structural colors, are produced by the keratin / air matrix of the spongy medullary layer of the barb ramus – air bubbles.
• However, the precise physical mechanism by which the human-visible and UV barb colors are produced remains controversial.
Bird Vision
• Birds can discriminate UV colors• Feathers that may appear one color to us can
be very different for a bird who sees the UV color, or patches of UV color
• Two species that look identical to humans can be dramatically different under UV light (think of flowers with UV patterns for bees)
Iridescence
• http://people.eku.edu/ritchisong/554notes1.html• About 40% of the way down the page– Sapphire vented puffleg– Hummingbirds