Subject: Re: hourse finch plumages - was orioles/genetics Date: May 3 17:43:38 1995 From: Jon Anderson - anderjda at dfw.wa.gov
My reading and understanding of male house finch plumage is that the yellow, gold, orange plumages are a result of a deficiency of beta- carotene in the individual bird's diet when the colored plumage is developing during each molt, and are *not* dependent upon genetics.
I have captured male house finches with red plumages, banded them, and have re-captured the same individuals years later with yellow or 'orange' plumage having replaced the red.
I will have to look up the reference for beta-carotene and get back to you tomorrow...
Jon. Anderson Olympia, WA anderjda at dfw.wa.gov
On Thu, 4 May 1995, Michelsen, Teresa wrote:
> Sex-Limited: This is the case that could fit house finches (and according > to my reference, accounts for the male peacock plumage). In this case, all > house finches have a gene somewhere for "basic" plumage, the brown streaky > plumage that juveniles and females have. Both M and F birds have this when > they are born. Somewhere else there is another plumage gene that both M and > F birds also have, but which is only expressed in the presence of male > hormones. So at some point in the male bird's life (bird puberty, if you > will), genes on the W chromosomes get busy cranking out male hormones and > the red plumage shows up in males, while the females stay brown. This > second gene is further complicated by having both dominant and recessive > traits (the red and gold varieties). As you can see, many bird species fit > this pattern. > > - Teresa Michelsen temi461 at ecy.wa.gov