On Jan. 19, 1999, Deborah Wisti-Peterson wrote:

>after seeing this bird, i have begun to wonder (yet again) why birders
>refer to birds with oddly-placed patches of white (or yellow) as
>"partial albinos" instead of "pied mutations," as do the aviculturists.

Albinism a term used by biologist to refer to an inability to make
pigment. It can be found in almost any species that has pigment including
plants (which don't survive for very long).

There are three degrees of albinism. Partial albinism, as you noted, is
an inability to make pigment in only a few locations. They can appear any
where in the body and may have more than location. Those areas are entirely
white in a bird (the basic feather color). Otherwise, the bird appears
perfectly normal and usually has normal colored eyes. Incomplete albinism
occurs when an animal can't make one pigment but can make the other
pigments. In the case of birds, there are several pigments involved in
making colors. We have an example of a female Evening Grosbeak that was an
incomplete albino. She could make yellow just fine but couldn't make the
melanin involved in making black and gray. So, she had the bright yellow
markings and was white where she should have been gray or black. Weird
looking bird. Total albinism is the form most people are familiar with. It
involves an inability to make any pigment at all. So, for bird's feathers
and mammal hair, that means white. For eyes, they are pink.

But back to your original question. It is sort of like asking why a
gardener calls some thing one thing and a botanist calls it another. To me,
an ornithologist by training, partial albinism seems like a better term.
Albinism is the word biologists have used to refer to the lack of pigment.
Partial because it is only part of the body that affected.

The term "pied mutation" has no meaning to me. First, it assumes that the
lack of pigment is due to a mutation. Probably but there are lacks of
pigment that are not due to mutation. For example, the some of the hairs on
my head used to have pigment; now they are white because the follicle cells
can't produce the melanin. Is that a mutation? Maybe. Could be other
reasons such as damage or lack of some element necessary for melanin. And
what the heck does "pied" mean? Black and white? Black and some other
color? I don't know but it doesn't mean much to me.

Much of the terminology for birding comes from biology because most of the
early birders were ornithologists or had some biology training. Few were
aviculturalist. I am a birder and an ornithologist (an a bunch of other
things) but I doubt I will ever be an aviculturalist. A few rare
individuals (including Deborah Wisti-Peterson) may be all three: a birder,
an ornithologist and an aviculturalist.

But, hey, you can call it what ever you want and it will still be an
odd-looking House Finch. (I wonder if it will find a mate?)

Cheers
Deb
Deb Beutler
Dept. of Zoology
Washington State University
Pullman, Whitman Co., WA

dbeutler at wsunix.wsu.edu
-----Original Message-----
From: Deborah Wisti-Peterson <nyneve at u.washington.edu>
To: tweeters at u.washington.edu <tweeters at u.washington.edu>
Date: Tuesday, January 19, 1999 7:33 AM
Subject: oddly-marked house finch spotted on UW campus


>
>hello tweets.
>
>last week, i noticed an oddly-marked bird hanging out with a group
>of talkative house finches. this bird had white cheeks and a white
>spot at the base of its upper mandible. the markings were so odd
>that i stopped dead in my tracks and just stared at it, not sure
>of its identity. the bird became nervous and popped up to a higher
>branch, where it apparently felt safer. at that point, it began
>to make its cheery call notes, and i realized it was a house finch.
>i then noticed that there were house finches all around it in the
>surrounding branches, and they were of both genders and in various
>stages of brilliant red coloring.
>
>after seeing this bird, i have begun to wonder (yet again) why birders
>refer to birds with oddly-placed patches of white (or yellow) as
>"partial albinos" instead of "pied mutations," as do the aviculturists.
>
> Deborah Wisti-Peterson email:nyneve at u.washington.edu
>Department of Zoology, University of Washington, Seattle, Wash, USA
> Visit me on the web: http://weber.u.washington.edu/~nyneve/
><><><>Graduate School: it's not just a job, it's an indenture!<><><>
>