Dis"oriented" Mandarin Ducks      

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Email from Edward van den Bergh:

I love the website, thank you for it. On page http://www.utahbirds.org/featarts/2004/MandarinDuck2.htm the last picture is of an odd looking Mandarin, which the site suggest may be a mandarin in eclipse plumage, however, may I propose that it is a rather more unusual specimen? I think it is a female Mandarin which has undergone a natural sex-change... this is not what most people expect, but if one (or both) of the ovaries becomes infected, it is possible for it to mutate to become a testis, and so to produce the duck version of testosterone. The plumage then becomes more male, even if the colours are more female (so grey) since the feather follicles are still the same and are coded for grey in the egg. They can then actually breed as males even if they look rather strange. Sounds very odd, but it's covered in a small book called the mandarin duck by Christopher Lever. He writes the following:

" a change of sex can occur in many birds, but in the case of the mandarin duck it is especially obvious because of the elaborate plumage of the male, which is surpressed by female hormones. In the females of most birds only the left ovary is functional; if it becomes damaged in any way ( for example by being shot ) the rudimentary right ovary sometimes increases in size and acts, not as an ovary, but as a testis, resulting in a change of sex"
Ducks in eclipse look like this:

With regards,
Edward van den Bergh

Photo in question by Ted Steinke


Mandarin Duck
 Aix galericulata

 Male or Female ? 
 Tracy Aviary
 Salt Lake City, Utah
 4 Jan 2003

 by Ted Steinke
 ŠTed Steinke



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