Xanthochroism

A Red-bellied Woodpecker with xanthocroism--showing yellow on the head where feathers are typically red. Photo by Debbie Mennell of Warrenville, Illinois.

The color variation called xanthochroism refers to yellowish or orange pigments replacing normal coloration, usually red. FeederWatchers often report seeing strangely colored House Finches that they believe have xanthrochroism. However, House Finch coloration varies widely, and research has shown that most of the variation is diet-related rather than a pigment abnormality.