Re: Albinism versus leucism
Mon, 16 Feb 2004
15:53:37 -0800
From: Joseph Morlan
Floyd Hayes wrote:
For years I assumed that Buckley�s terms and definitions were generally accepted by the ornithological community - but perhaps I�m mistaken. Frank Gill's 1st edition of Ornithology ignores the subject (I don't have the 2nd edition). I�m left wondering who coined the term leucism to replace partial albinism and when it was first proposed. And I�m wondering if a consensus even exists on terms and definitions for abnormally plumaged birds. If anybody could enlighten me further I'd be delighted.
Thank you for the interesting historical perspective.
The use of these terms was discussed on BirdChat about three years ago; the thread archive starts at
http://listserv.arizona.edu/cgi-bin/wa?A2=ind0104a&L=birdchat&F=&S=&P=8452...and I found my contribution as follows:
On Thu, 5 Apr 2001 08:23:15 -0400, Gerry Rising wrote:
He refers the reader to Harrison, J.M. 1964. "Plumae: Abnormal and aberrant" in A New Dictionary of Birds, a book to which I do not have access.I have the 1985 edition of A Dictionary of Birds edited by Campbell and Lack. An entry by C. J. O. Harrison lists the following types of abnormal plumage:
Abnormal Pigmentation, Atypical pigmentation, Schizochroism, Pigment replacement, Gynandromorphs, Pigment deficiency, Pattern variations, and Feather structure abnormalities.
The following appears in the discussion under "Atypical pigmentation":
Partial loss of pigment, affecting all the colours present and reducing them in intensity, is rare. It is called "dilution" by bird breeders and "leucism" in scientific writings, although the latter term is also used at times for various forms of schizochroic loss (see below) of single pigments which make the plumage appear paler....So defined, the phenomenon of true leucism (dilution of all pigments) is much rarer than schizochroism (involving a loss or dilution of only some pigments), so leucistic should probably be used rarely, and not merely as a jargon replacement for the more popular vernacular partial albino....
Joseph Morlan, Pacifica, CA
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Redheads in Livermore
Mon, 16 Feb 2004 18:17:48
-0800
From: Steve Huckabone
I found 4 Redheads in the gravel pit lakes off El Charro Rd. The 4 Redheads are with a mixed flock of 200+ Ring-Necked Ducks and 45 Canvasbacks. In the past the roads that go south from Hwy 580 at El Charro were marked "Private". They recently rebuilt the bridges and paved the roads and I didn't notice the "Private" signs. Does anyone know if these roads are still private? I also found 30 to 35 Tree Swallows flying low over one of the ponds and located a few Tricolored Blackbirds in the horse paddocks.
I refound the 4 Blue-winged Teal this afternoon - two were at the small pond at the corner of Dalton Ave & Ames St and two at Frick Lake.
At Del Valle Regional Park there were 30 to 40 White-throated Swifts at the usual location over the bridge.
Good birding.
Steve Huckabone
Alameda County
Livermore California
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Re: Albinism versus leucism
Mon, 16 Feb 2004
18:36:13 -0800 (PST)
From: Floyd Hayes
As with definitions for species, hybridization, migrant birds, etc., this appears to be yet another instance in which there is no consensus among biologists. Individuals generally adopt whichever set of terms and definitions they're first introduced to by an "expert" and stick with it (in this instance, Buckley or Harrison, though perhaps without realizing it; for what it's worth, Buckley insists that Harrison's use of albinism and leucism are incorrect!). Which means we'll have to live with a confusing plethora of imprecise terms. It would be nice if there were some international organization that would standardize terms and definitions.
In the meanwhile, Larry Tunstall gave the best advice: "Sounds like a careful description of the bird is the only way to avoid confusion about what you mean." This echoes what J. P. Hailman (1984. On describing color abnormalities in birds. Florida Field Naturalist 12:36-38) wrote: "...terms that are used ambiguously in the literature, or that connote an unwarranted interpretation of the coloration observed, should be avoided in descriptions."
Floyd Hayes
Angwin, CA
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