[EBB Sightings] Steller's Jay Oddity - color blue

[EBB Sightings] Steller's Jay Oddity - color blue

janniedres
Mon Jul 06 07:34:59 PDT 2009
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    Many thanks for the very clear explanation!
    Jannie Dresser
    Berkeley
    ----- Original Message -----
    From: "Ralf Stinson" 
    To: "Donald Lewis" , "MDAS Sightings" 
    Sent: Monday, July 6, 2009 7:08:09 AM GMT -08:00 US/Canada Pacific
    Subject: [EBB Sightings] Steller's Jay Oddity - color blue
    
    With the exception of a few birds in the old world, no birds have blue
    pigmentation in their feathers.  A pigment is a chemical that absorbs light
    of colors that it is not (red pigment absorbs green & blue light, so it
    looks red).  If you put clear oil on water, you see all the colors of the
    rainbow being reflected.  So the colors you see are not from any pigment,
    but from light interference pattern on the thin oil film.  There are
    microscopic structures in the feather that produce the blue reflected light.
    So for the blue head of the Jay, the microscopic structures were missing, or
    the angle of the light was such that you did not see the blue.  The dark
    blue color comes from brown pigment and the blue refecting microscopic
    structures.  I have seen bluebirds appear brown because of the lighting.
    After it moved into sunlight, it appeared blue.
    
    Ralf Stinson
    
    -----Original Message-----
    From: sightings-bounces at diabloaudubon.com
    [mailto:sightings-bounces at diabloaudubon.com] On Behalf Of Donald Lewis
    Sent: Sunday, July 05, 2009 22:40
    To: MDAS Sightings
    Subject: [EBB Sightings] Steller's Jay Oddity
    
    Sunday morning,  a Steller's Jay with a totally brown head was feeding a
    fledgling on our deck. I've never seen a Jay like that. I guess a form of
    less-than-normal pigmentation but I'm curious if others have seen a similar
    bird.
    
    Don Lewis
    Lafayette, CA
    donlewis at comcast.net
    
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