well ... it's more difficult to know with mallards, since so many domestic
(white) ducks are hybridising with wild mallards. however, that said, i
assume the genetics of colour are similar to songbirds, at least.


On Tue, Aug 9, 2016 at 5:55 PM, Diane W <diane_weinstein at msn.com> wrote:

> In my area there have been several generations of extremely pale
> mallards. Is this the same type of thing as the brown crow?
>
> This year there was a pale female mallard with two pale ducklings that
> hung out in my yard and out at the pond. Of the two ducklings, now fully
> grown, one is a male and the other is a female.
>
> Diane Weinstein
> Issaquah
> *From:* Devorah the Ornithologist <birdologist at gmail.com>
> *Sent:* Tuesday, August 9, 2016 3:08 AM
> *To:* Terry Sargent Peart <terry.peart at outlook.com>
> *Cc:* Tweeters <tweeters at u.washington.edu>
> *Subject:* Re: [Tweeters] Brown Crow?
>
> hi terry,
>
> it sounds like this crow has a genetic mutation that has knocked out one
> of its melanin producing enzymes, which probably prevents it from producing
> eumelanin. in captive-bred songbirds, this usually is a sex-linked mutation
> known as "fawn" or "isabella". there are two mutations that can be visually
> recognised. one gives the black regions on the bird a red-brown colour
> whilst the other gives the black regions a (paler and less red) beige-brown
> colour.
>
> hope this helps.
>
>
> On Tue, Aug 9, 2016 at 2:47 AM, Terry Sargent Peart <
> terry.peart at outlook.com> wrote:
>
>> I work in Maple Valley at the Cedar Hills Regional Landfill. Yesterday,
>> I saw a Brown Crow... I was stunned. I had my good bins with me and got a
>> good look at it. It was with a few other crows (black) so I was able to
>> compare it with them. It was the same size, same beak, acted the same
>> (they were on the asphalt parking lot picking at probably maggots that fall
>> out of our garbage trailers). The color was even over the whole bird for
>> the most part, even the beak. I would compare the brown with that of a
>> cowbird.
>>
>> I've never heard of a brown crow, so what did I see?
>>
>> Thanks for your help,
>>
>> Terry
>> West Seattle
>>
>> _______________________________________________
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>> Tweeters at u.washington.edu
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>>
>>
>
>
> --
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> Devorah Bennu, PhD
> birdologist at gmail.com
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--
GrrlScientist | at GrrlScientist <https://twitter.com/GrrlScientist>
Devorah Bennu, PhD
birdologist at gmail.com
Blogs: Forbes <http://www.forbes.com/sites/grrlscientist/> | Evolution
Institute <https://evolution-institute.org/profile/grrlscientist/?source=> |
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Keep up with my writing: TinyLetter <https://tinyletter.com/grrlscientist>
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