Wednesday, February 8, 2012
Photo Quiz solution and Aberrant Plumages in Birds
Another part of the quiz, though, was determining what was causing this bird to look so odd. So far I've used the terms albinistic and leucistic. Albinism is the absence of melanin anywhere in a bird, so an all white bird (although sometimes with some color from pigment other than melanin) and red/pink eyes is always called albinistic. For the purposes of this quiz, I accepted the terms leucistic, partially leucistic, and partially albino since these terms are often used to mean the same things. However, it is important to point out the differences in these terms, and why certain terms are less accurate. Since partial albinism means partial complete absence of pigment, it makes little sense, and is generally not used as frequently anymore. However it used to be used quite frequently to describe the pied appearance as is seen in this bird.
Leucism generally describes two phenomena, a pied/piebald patterning (patches of feathers/skin with no pigment (i.e. they are white patches) as in this bird, or an overall reduction of pigment evenly over the entire bird giving the bird a faded appearance. One of the players on this quiz pointed out that he does not like the term leucistic since it describes multiple problems. Still, both phenomena termed leucistic stem from the same problem - a pathology that causes melanin and other pigments to be deposited aberrantly. This is opposed to albinism, which means the bird presumably cannot make melanin at all. This bird has pigment, but also appears to be faded in some parts, and yet completely white in others. I would call this bird leucistic, but if anyone still believes otherwise, I encourage you to comment on this post.
Thanks for playing!