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Tuesday, November 13, 2018

White-headed Junco, Speckled Robin, what??? Leucistic Birds


House Sparrow, female, leucistic

We often get people sending us bird photos to identify, and nothing mystifies people more than seeing birds with strange white blotches. These are leucistic birds, normal species that are missing some of the pigment in their feathers. I photographed this female House Sparrow in GA.

House Sparrow, female, leucistic

House Sparrow, female, leucistic

This leucistic Dark-eyed Junco photo was sent to us by Dianne Connolly of NH.

The white blotches make an interesting pattern on its head, neck and throat.

This amazing photo of a leucistic American Robin against snow was sent to us by Bud Marschner,

of Fairbanks, AK. Bud is one of the wonderful photographers in our best-seller Stokes Field Guide to the Birds of North America.

Leucisim in birds, is a genetic mutation that prevents pigment, especially melanin, from being deposited in a normal way on a bird's feathers. Usually the leucistic areas are noticeable on birds with black or brown feathers, as in the above cases. Leucistic birds may have white splotches, or look paler or bleached. This is different than albino birds. Albinism is a genetic mutation that prevents the production of melanin in a bird's body. Albino birds usually appear all white with a pink eye. Scientists are still working out what these two conditions are and how they affect birds.

Birds with leucisim or albinism may have a harder time in the wild, as they may be more visible to predators and not as attractive to a potential mate.

Leucisim is very rare in birds. Thus, when 3 people living in neighboring towns in NH reported leucistic juncos to us on about the same day, we found this very interesting. 

If you see a strange looking bird with whitish areas in its plumage and you cannot identify it in your field guide, look very carefully at its size and shape and what other birds it is hanging out with. Our new field guide begins each species account with a thorough description of that bird's shape. If your mystery bird looks exactly like a robin or junco or other known species, but with weird white areas in its plumage, then it may be a leucistic bird.

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