I can find only one reference in the Encyclopedia of North American Birds
and it refers to leucism only as being "closely allied to albinism", under a
discussion of schizochroism (another word not found in Webster's) under the
heading "Color of Feathers".
In googling I see this word discussed briefly on another list last year,
with no conclusive definition found.
It's interesting that a word as widely used as this one doesn't seem to have
an authoritative definition. There are a few from various websites but
nothing I can find from a recognized English language dictionary or
encyclopedia, although admittedly I don't have access to many. I sure hope
someone comes up with something. I would like to be sure of it's meaning.

Joseph Higbee
Spanaway, WA
mailto:jvhigbee at hotmail.com