[wisb] Re: About Brown Feathers
- From: Jesse Ellis <calocitta8@xxxxxxxxx>
- To: "wisbirdn@xxxxxxxxxxxxx" <wisbirdn@xxxxxxxxxxxxx>
- Date: Thu, 28 May 2009 08:58:32 -0500
Hello wisbirders-
If I understand Marge's description and photo correctly, every black
area on the Downy is brownish. This seems unlikely to come from nest
tree staining. My reasoned guess is that the bird is leucistic in
some fashion, with the biochemical chain leading to heavy melanin
deposition in the feathers (which would produce black) being
interrupted somewhere along the line, and leaving a brown color. I
hadn't heard of this in a woodpecker before, but it's not terribly
surprising given how common it is.
Mitch's photos below are interesting too. The first DOES seem to be
some sort of bleaching or staining (in the Hairy Woodpecker). The
Grosbeak, however, looks like it had some sort of developmental
stress when those feathers came in, leading to the off-color only in
the primaries. I'm not a molt expert, but I'd rule out differential
wear due to molt because most of the feathers look worn already. If
the primaries were the only feathers left from juvenile plumage,
they'd look terrible next to his new adult set. Both look fairly worn
in that photo.
My two cents.
Jesse Ellis
Madison, Dane Co.
At 5:17 AM -0500 5/28/09, Mitch wrote:
>Hi All,
>
>I first heard about this and saw images posted on a bird forum two
>winters ago. The images were of a Hairy woodpecker in Ontario and the
>speculation in the forum and from subsequent searches by me ran from
>tannin on the feathers from the inside of the nest hole, to speculation
>that feathers on juvie birds last longer before first molt, and the
>feather is just dead. Neither of which explains why the white bars on
>the same feathers whose black areas are no brown, didn't also turn
>brown. Tree tannin would certainly discolor the white and the black
>areas equally, but no image ever showed that. Heck, it could even be
>sunburn from the thinning ozone layer.
>
>However, I am now trending toward the juvie feathers lasting longer and
>discoloring than any of the other theories. Because I have since shot
>what looked like young looking hairy's with brown feathers, and the
>other day, a second year male Rose Breasted Grosbeak in my yard with the
>same browning feathers. I'm no scientist though, I just collect the
>images. :o)
>
>Here are two, one Hairy and one of the Grosbeak;
>http://www.picturelacrosse.com/birds09/mixed1/brown-hairywpf-img_3294-012709.jpg
>http://www.picturelacrosse.com/birds09/mixed1/rose-breasted-grosbeakm-1d2n7525-052809.jpg
>
>Thanks,
>Al Mitchell-
>La Crosse, La Crosse County
>http://www.picturelacrosse.com/
>
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--
Jesse Ellis, Ph. D.
Madison, WI
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