One thing that may be going on now is that the Anna's are probably cold, and
therefore fluffing their feathers up more for warmth. The color of the
interior barbs of the feathers may be different than the outer edge (or may
refract differently). Combine that will Al's hypothesis and maybe...

== Michael Hobbs
== Kirkland, WA
== http://www.marymoor.org/birding.htm
== http://www.marymoor.org/BirdBlog.htm
== birdmarymoor at verizon.net

----- Original Message -----
From: "Al Wagar" <alwagar at verizon.net>
To: "Jim Greaves" <lbviman at blackfoot.net>; <tweeters at u.washington.edu>
Sent: Tuesday, December 23, 2008 3:53 PM
Subject: Re: [Tweeters] Yellow Anna's


> Jim,
>
> I suspect much of the color we see (with eyeballs) is from the feathers'
> diffraction-grating effect rather than pigment. May be that when the main
> light source is from camera, rather than from side, you get a different
> part
> of the spectrum. Anyhow, it's a hypothesis.
>
> Al Wagar
> Shoreline
>
> On 12/22/08 2:07 PM, "Jim Greaves" <lbviman at blackfoot.net> wrote:
>
>> Regarding yellow Anna's -- I notice when using flash on Anna's that
>> the back gets a yellow hue to it -- sometimes so much so that it
>> overtakes the greens, and I think I've set the camera wrong! There
>> must be some subtle shades in the feathers (much like reds and
>> yellows overlapping?) that we do not readily see until we've somehow
>> captured it -- do you use flash? -- Jim Greaves, Thompson Falls MT
>>
>>
>
>
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