Leucistic Junco

Day 311: Leucism is the result of mutations in the genes producing melanocytes. In birds, it manifests as washed-out colouration, blotchy patches and/or white feathers. Unlike albinism, a leucistic bird's eyes keep their normal colour. The predisposition can be and often is passed on genetically to subsequent generations, so I am left wondering if this youngster is kin to Snowflake, a visitor at my feeders in the winter of 2010 (Snowflake in the Filbert). In the years since, I have almost always had one leucistic Dark-eyed Junco (Junco hyemalis) in my flock. Some had white tails, some white wing feathers. Some, like Snowflake, had white on their faces or heads. One was a "watercolour" version, as if someone had bleached every feather. At first, I thought this was a juvenile in moult, but the overall lightness and abnormally pale beak convinced me otherwise. Strikingly obvious when he flies, the central two feathers of his tail are dark.