[Maine-birds] Correction: LEUCISTIC Common Grackle today - Southwest Harbor MDI

Thanks to the friendly nudges from several of you on the list, and thanks to a technical article from Louis Bevier, I think Leucistic is the term I should have used to describe today's cool grackle. I've revised my eBird list also.

Leucism
Leucism is defined as a partial or total lack of eumelanin and phaeomelanin in the feathers as a result of inherited disorder of the deposition of these pigments in the feathers. It is probably the most frequently occurring inheritable colour aberration in birds and it is most often – erroneously - called albinism or 'partial albinism'. In leucistic birds, the enzyme tyrosinase is normally present and the production of melanin in the basic colour cells and the transformation into colour cells is normal. However, the deposition of melanin in the feather cells does not occur due to an inherited disturbance disorder of the pigment transfer. As a result, more or less colourless (white) feathers occur at random anywhere in the plumage. Different forms of leucism are known and can vary from only a few white feathers (<25%) to totally white individuals (100%).

Not every white bird is an albino: sense and nonsense about colour aberrations in birds Hein van Grouw, Dutch Birding 2006

Cheers,

Craig

On Sat, Oct 31, 2020 at 12:21 PM Craig Kesselheim <ckesselheim@gmail.com> wrote:

Hi all - We had one albinistic Common Grackle in our feeder flock today. I managed to take a few photos and upload them to eBird, fyi. It was a lovely pale salmon (cafe au lait?) color, and it showed a slightly darker cast to the head and upper body where normal grackles have their purple sheen. 

I'd appreciate hearing back if you have further thoughts, or can't access the list.

List here.

Also 6 Evening Grosbeaks briefly visited our treetops, but we didn't see them at the feeder. Also, my first of fall Am. Tree Sparrows arrived for the winter.

Best,

Craig K

Southwest Harbor

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