House Sparrow (Passer domesticus) Leucistic

Leucistic birds have less pigmentation than normal, so they will appear white or pale, in varying degrees. This is not an albino since there is some pigmentation and the eyes are not pink.

 

Leucism is a general term for the phenotype resulting from defects in pigment cell differentiation and/or migration from the neural crest to skin, hair or feathers during development. This results in either the entire surface (if all pigment cells fail to develop) or patches of body surface (if only a subset are defective) having a lack of cells capable of making pigment.

Done