Why Is This Bird Half-White?

This audio story is brought to you by BirdNote, a partner of the National Audubon Society. BirdNote episodes air daily on public radio stations nationwide.

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’s 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—or sometimes all—of 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’m 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’s 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

© 2018 Tune In to Nature.org  May 2018