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Another ID request (1 Viewer)

beerbarrel

New member
United States
Walking thru the park, and noticed a white flash. Didn't get a real good
chance to set up for the pix. it was quick to move on.
Any one have any ideas ??
 

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It is a leucistic American Robin. I have seen them in the past, but usually the ones I see are not this "extensively" white feathered. Nice Photo!
 
Larry Lade said:
It is a leucistic American Robin. I have seen them in the past, but usually the ones I see are not this "extensively" white feathered. Nice Photo!

Isn't Grousemore right with albinsitic (or at least partially so) rather than leucistic?
I always thought that albinism resulted in extensive white patches and, on occasion, fully white birds with pink bare parts. Whereas leucism is pretty much just a reduction in pigmentation which results in pale looking birds.
 
I'd agree, partial albino American Robin. CJ's right, in leucism the normal colours are present, just pale, 'washed out'; this bird has pure white patches with other parts having the full normal colour

Michael
 
Michael rightly corrected me in the Gallery section for my improper use of the term leucistic. For those not too clear on these terms here is what the Cornell Lab of Ornithology has to say about it.

• Albinism: All- or partially-white plumage. Albinism results from a genetic mutation that interferes with production of the pigment melanin. Birds that lack not just melanin but all pigments are called true or complete albinos. As well as pure white plumage, they lack pigment in their skin and eyes. Partial albinos have a pied appearance, with patches of pure white feathers.
• Leucism:Extra-pale plumage. Leucism is related to albinism, but in this case the normal pigmentation is diluted rather than lacking, resulting in birds whose plumage is lighter than normal, but not pure white. Plumage patterns, such as a mask or wingbars, often remain detectable.
• Melanism: Extra-dark plumage. Melanistic birds have a genetic mutation that results in an excess of dark pigmentation. Some cases also result from diet. Some species have a naturally occurring melanic form (or "morph"), for instance the Red-tailed Hawk.
• Xanthochroism: (sometimes xanthism or xanthochromism) Yellowish or orange plumage (usually instead of red). May be caused genetically or by diet.
• Erythrism: Reddish or rufous plumage. Some species have commonly occurring rufous form, for instance the Eastern Screech-Owl.

Steve
 
Jane Turner said:
Are American Robins as prone to albinism as Blackbird (Turdus merula)?
I don't see why not. The main factor affecting abundance of partial (& full) albinos is (as far as I can tell) any shortage of natural predators like Sparrowhawks (partial albino Blackbirds are far less common since Sparrowhawk numbers recovered), and still the shortage of Goshawks allowing albinistic crows to survive well. Two reasons: (1) albinos are very visible, and (2) albino feathers are far more prone to wear and degradation in sunlight, so the birds often can't fly very well. So they're easy targets for predators.

Michael
 
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