Here is a first for us.  We learned a new word and saw a relatively rare bird.  The word is leucistic.  It is a genetic deficiency resulting in a lack of pigment.  The reason we needed to learn this new word is that we had a young leucistic red-winged blackbird.  While many of the images of leucistic black birds are not entirely white.  There are white patches at various locations on the birds.  Ours was completely white.