[CT Birds] white blue jays

COMINS, Patrick PCOMINS at audubon.org
Thu Mar 22 14:34:16 EDT 2007


Richard Prum would be the best one to comment, but there are certainly both pigment-based and structural factors that can cause color in birds.   Black would be pigment-based (melanin) and all (?) blue pigments would be structural.  From the description of this bird, it would seem that the problem is a structural abnormality, since the blue is what is missing and the black is still there.  

There is a good discussion of aberrant coloration in birds here:
http://www.birds.cornell.edu/AllAboutBirds/attracting/challenges/strange_birds

Generally any iridescent colors would also be structural.  Another good discussion of this can be found here:
http://www.birds.cornell.edu/AllAboutBirds/studying/feathers/color/document_view

Patrick Comins, Meriden.







-----Original Message-----
From: ctbirds-bounces at lists.ctbirding.org
[mailto:ctbirds-bounces at lists.ctbirding.org]On Behalf Of Anthony Zemba
Sent: Thursday, March 22, 2007 1:52 PM
To: ctbirds at lists.ctbirding.org
Subject: [CT Birds] white blue jays


Not all colors in birds are a reflection of light. It is true that blue is not the result of blue pigment, but rather a result of how color is reflected (or absorbed)from the feathers. Some colors are derived from pigments. And still others occur as a combination of both. THe retainage of black suggests that melanins (a common pigment in birds) were not reduced as in the case of albinism and therefore the bird may simply be leucistic and not a partial albino. But don't quote me on that. ANyone else?


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