Evening Grosbeak partial ? albino
Hi, this is my first post. great stuff i've seen here so far.
This Evening Grosbeak was hanging around my in-laws' feeder around Christmas last year (rural Sask. north of Melfort). That it is some kind of pigmentation problem is obvious. Is this classified as albino or partial albino?
How rare is this sort of pigment problem?
He disappeared after a few days, maybe stood out too much for his own good.
Welcome Thomas....this is one way cool Grosbeak...I will let the experts in here comment on pigmentation...I've been birding a long time, seen many Evening Grosbeaks, never have I seen one like this.
The link below will explain some of the different colors, off color, Grosbeaks can be....its a little old but only thing I found on line.
http://images.library.wisc.edu/EcoNa...n01.mshaub.pdf
When I used to breed cage birds this would be classed as a lutino (albino of the green colours). Was the eye red?
Thanks for the link, Paul. It shows at least that it is not unheard of. One of the described birds sounded quite similar to this one.
Roy: The eyes were normal colour.
That really looks very unusual and I'm wondering if leucistic is the right term. Maybe ornithologists can pitch in.
Axel: That is a new term for me. I googled it and came up with this link:
http://www.wildlifeextra.com/go/news/leucism.html#cr
Seems right to me, and I've learned something again Thanks!!
Interesting link with good examples. Thanks for sharing it.Originally Posted by Thomas Boysen
Really fabulous to see this! First, for the Europeans in the audience, Evening Grosbeaks are the North American version of the Hawfinch- genus Coccothraustes. As Axel mentioned, this looks like a "leucistic" individual, which means it has a reduced level of pimentation. Note the eye is dark which tells you that the individual is not albino- in this case the eye would be pink. Wikipedia has quite a good article on this subject:
http://en.wikipedia.org/wiki/Leucism
Leucistic comes from leukos which means white in Greek. The Bald Eagle is Haliaeetus leucocephalus, the last word meaning "white-headed". Note that although leucistic individuals often show white in the plumage, they do not have to be white. In the case of this Evening Grosbeak, the dark ochre yellow is just a much lighter lemon yellow in the leucistic bird.
Just to chime in... I've typically heard this called an aberrant plumage, which includes leucism but I would be more inclined to call it leucistic if there was more pigment loss.
Doug- I'm not sure if there is a line you can draw between the two. Sometimes you see a "leucistic" crow with a small patch of white feathers in its wing, everything else being normal. I personally think that this would be an appropriate use of the term. I think to some degree the result of reduced pigment depends on the normal, base colour. An ochre feather as in an Evening Grosbeak may turn bright yellow with the lack of a certain pigment but a black feather may go completely white. It all depends on what pigments produce the colour in the first place. Kind of like CMYK colour rendering in printing- lose the black from a black object and you have white, lose the cyan from a coloured object and you get whatever the remaining pigments create.
Last edited by John Chardine; 05-05-2009 at 06:41 PM.
I agree there is no line between the two, I'm just throwing out another term... Sorry.
Nothing to be sorry for Glen. Good discussion! That what it's all about!
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