Chestnut-backed Chickadee (Poecile rufescens barlowi) 3 September 2014, Pacifica, San Mateo County, CA Photos © 2014 Joseph Morlan

Jeff Davis has commented, " It appears to be hypo-eumelanistic.....The gray on the hind neck and tail suggests eumelanin pigments are present but in abnormally low concentrations. Phaeomelanin pigments, which seem to be at normal levels, are responsible for the chestnut on the back as well as on the cap and sides and even the tail and wings, where that color is normally masked by darker eumelanin pigments."

Personally I'd call it partial leucism - The eumelanins are dilute (leucistic) producing the gray colors. But the phaeomelanins which produce the chestnut color are normal.

Nikon P510 - Point & Shoot.
[ Back to Photo Gallery ] [ Home ]