Leucism is a genetic condition that affects the pigmentation of feathers in birds. It can occur in any bird species, although it is more commonly observed in some species than others. The extent and pattern of leucism can vary greatly between individuals and even within a single bird’s plumage.
In theory, any bird can be leucistic as long as it carries the genetic mutation responsible for this condition. However, the occurrence of leucism in a population or species can be influenced by several factors. For example, certain bird species may have a higher prevalence of leucism due to a higher frequency of the genetic mutation within their population. Additionally, birds with more conspicuous or vibrant plumage may be more likely to be noticed and reported as leucistic, while those with more subtle coloration may go unnoticed.
I have personally observed leucism in a variety of bird species, including common backyard birds such as American Robins and Northern Cardinals. In these cases, the affected birds displayed patches of white feathers amidst their normal colored plumage. It is worth noting that leucism can affect different feathers to varying degrees, so some birds may have only a few white feathers while others may appear almost completely white.
It is also important to distinguish between leucism and albinism in birds. While leucistic birds have reduced pigmentation in their feathers, their eyes, bills, and other soft tissues usually retain their normal color. In contrast, true albino birds have a complete lack of pigmentation not only in their feathers but also in their eyes, bill, feet, and legs. Albino birds typically have pale pink or red eyes and very light-colored or white bills and legs.
While any bird species can potentially be leucistic, the frequency of occurrence may vary between species. Leucism affects the pigmentation of feathers, but the eyes, bill, and other soft tissues usually remain unchanged. True albino birds, on the other hand, have a complete absence of pigmentation in both feathers and soft tissues.