http://www.biology.eku.edu/kos/yellow_NOCA.htm Now this is interesting and very pretty for a mutation!
Subject: RPT: Yellow pigmented Northern Cardinal
From: "Palmer-Ball, Brainard (EEC)"
Date: Wed, 2 Feb 2011 16:25:15 -0500
Thanks to Kate Heyden with Ky Dept of Fish and Wildlife Resources for
forwarding along pictures of the *neatest* bird I've seen in a long time ... a
yelllow-pigmented Northern Cardinal! The photos were taken by David Gourley,
who lives in Boyle County. He and his wife have seen the bird at their feeders
several times since January 20th. I sent the photos to bird pigment expert, Dr.
Geoffrey Hill of Auburn University. Some may recall Dr. Hill gave a couple of
nice programs to the Ky Ornithological Society a few years ago. He said this is
a very rare mutuation; he published a paper on a similar specimen in the
Louisiana State University collection several years ago, a copy of which can be
read (you'll have to read slow ... it has more technical terms in it than any
pub I've read in a long time!!!)