Well, I'm not an expert in feather pigmentation, but it looks like a lack of
eumelanin.



Melanin is a pigment that both mammals and birds have. The form of melanin
called eumelanin produces black, dark brown, and grey colors. The form of
melanin called pheomelanin (sometimes spelled phaeomelanin) produces
yellows, reddish shades, tans, and browns. In mammals, those are pretty
much the entire choices. Mammal fur colors are due to various combinations
and patterns of eumelanin, pheomelanin, and/or the absence of either one
(i.e., white).



Bird feathers can be colored by melanins, plus many other pigments, such as
carotenoids (which they primarily get from plants in their diets), and a
bunch of other interesting pigments.



Most blues in birds, however, are not due to any exotic pigments; they are
created by the way melanin is deposited so it reflects light to appear blue.
Grind up blue feathers and you get a pile of gray or black feather dust.
Blue in bird feathers is a trick of light, as is iridescence.



Back to the mallard. The bird most likely has pheomelanin but little or no
eumelanin. The feathers where pheomelanins are deposited are a light brown
but the areas that are normally black, gray, or blue (because the blue is
created by eumelanin) are not pigmented.



As to whether the bird is a wild bird with a genetic defect or a feral
domestic bird, that I can't answer.



Kelly Cassidy



From: tweeters-bounces at mailman1.u.washington.edu
[mailto:tweeters-bounces at mailman1.u.washington.edu] On Behalf Of Hank Karen
Sent: Wednesday, January 23, 2013 11:19 AM
To: Tweeters
Subject: [Tweeters] Unusual colored Mallard(?)



What is the explanation for the colors of this Mallard?



http://www.flickr.com/photos/ljcouple/8408211565/





Thanks.

Hank Heiberg

Lake Joy

Carnation, WA

karenhankatyahoodotcom