Leucism?
"Leucism is characterized by reduced pigmentation, resulting in an individual with white or brighter patches of fur, plumage or skin than in the typical representative of the species. The phenotype may be inherited, or due to a mutation during the individual's developmental phase, but in many cases it is due to lack of proper nutrients. Some types of leucism are called partial albinism. F.e. some urban crows[1] exhibit this phenotype. The variations in feral dove's plumage exhibit the hereditary traits."