Why Is This Bird Half-White?
Unusual genetic mutations can eliminate color in a bird's feathers鈥攊n patches, or even across its entire body.
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Transcript:
This is BirdNote.
Sometimes a real puzzler of a bird turns up. It might look like a regular robin, but with frosty white splotches on its head or back.
Or within a flock of blackbirds, a single bird jumps out because it has white instead of black wings.
What鈥檚 going on? The abnormal feathers on these birds are the result of a genetic condition called leucism (pronounced LUKE-ism), which prevents pigments from reaching some鈥攐r sometimes all鈥攐f a bird's feathers. The degree of leucism varies with a bird's genetic makeup. But the skin and eyes remain their normal pigment and color.
Albino birds are distinctly different. Albinos are entirely white with pink eyes and skin. Albinism has a different origin, too: problems with an enzyme called tyrosinase (pronounced ty-RAHS-in-ayse). Problems with tyrosinase lead to problems making melanin, the pigment that gives skin, feathers, and eyes their color.
You are much more likely to see a leucistic bird than an albinistic one. Keep an eye out for birds that have white patches or washed-out plumage. It could be a bird of any species. Find photos of a few on our website: BirdNote.org.
I鈥檓 Michael Stein.
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Credits:
Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Recorded by Robert Bethel and Bob McGuire. BirdNote鈥檚 theme music was composed and played by Nancy Rumbel and John Kessler.
Producer: John Kessler
Managing Producer: Jason Saul
Associate Producer: Ellen Blackstone
Narrator: Michael Stein
Written by Bob Sundstrom
漏 2018 Tune In to Nature.org May 2018