Club member Barb Zimonick had the good fortune to photograph a rare condition in birds called leucism. Here is how Barb describes the sighting. I saw this bird on Oct 11, 2020 while driving up O’Connor Road, west off Westsyde Road just before Jamieson. It was sitting in a tree-top quite far away but the white caught my eye. At first, I thought it might be a snowy owl since that is the only white bird of this size familiar to me. However, the photo screeched hawk. I really did not know what species it is so posted the photo to a few bird groups on FB. Several accomplished birders confirmed that it is a leucistic Red-tailed hawk.

Leucism is the total or partial lack of pigments (melanins) in the skin and associate hair or feathers. It results from a genetic mutation and is inherited, being passed on to some offspring. Eye colour, however, is normal. You can see the dark eye colour in these photos.

Plumage coloration in birds is mainly the result of the deposition of pigments in the feathers. The most important pigments in bird coloration are carotenoids (red and yellow coloration) and melanins (brown and black coloration). Abnormality in the deposition of pigments produces colour aberrations, the most common being with melanin‐based pigmentation. In birds, leucism is characterized by having white patches in the feathers, but normal coloration in eyes, bill, skin and feet). 

Leucism is different from ablinism. Vertebrates with albinism are not only white (or sometimes pale yellowish) in colour, but also have very pale eyes, often pink or red. Leucism is only a partial loss of pigmentation, which can make the animal have white or patchily coloured skin, hair, or feathers.

More information is found in this article: Journal of Avian Biology, https://onlinelibrary.wiley.com/doi/full/10.1111/jav.01778   Factors associated with leucism in the common blackbird Turdus merula.