There are plenty of records of Zonotrichia hybidization,
but the bird described by Dan Lindsey is, as has already
been suggested, more probably a 1st winter (second year)
Golden-crown Sparrow. I spent one spring day during the
peak of the migration sketching zonos (at one point Dan
Fay had over 200 in his backyard).

Some of my notes can be seen at:
http://home.pacifier.com/~mpatters/details/zono.GIF

--
Mike Patterson
Expounder of Scientific Wisdom
Astoria High School, Astoria OR
http://columbia-pacific.interrain.org/ahscience/

In the beginner's mind
there are many possibilities;
in the expert's mind
there are few.
--- Shunryu Suzuki