Who is That Masked Robin?
Partial Albinism

Photo Doug Wilson
Why does this robin look unlike most robins? If it could speak English, it could tell us what caused its strangely fascinating pattern. Since it can’t, we can only make guesses. You'll do that soon, but first see terms to know:
  • Pigments are the chemicals in our bodies that give us our colors.
  • When a bird or other animal makes no pigments, the condition is called albinism, and the animal is called an albino. Albino animals make absolutely no pigments; their eyes are colorless, appearing pink or red from the color of the blood vessels within.
  • Some birds produce low-levels of pigment throughout their bodies. These usually appear very washed out and pale, but are not white. We call this leucism or dilution.
  • Some birds are genetically capable of producing normal pigments, but for some reason have all-white feathers in parts of their bodies. The rest of their plumage is normal. These are called partial albinos.

What Causes White Feathers on Birds That Are Normally Colorful?
When birds suffer serious injuries, sometimes replacement feathers grow in pure white. These injuries could include such things as:

  • losing feathers after narrowly escaping from a hawk or cat;
  • bonking repeatedly into a window; or,
  • recovering from a horrible case of lice or mites.

What else can cause white feathers? Some birds seem to grow more and more white feathers as they age. Robins often grow more white feathers on their faces and throats as they get older. But not all partial albinos get their peculiar and interesting color patterns from trauma or age. In some birds this seems to be a genetic condition, with patches of skin on both sides lacking pigment from early in life. These partial albinos seem to show perfect symmetry in their white patches. And some birds lack a particular pigment, but not others. Journey North’s science writer Laura Erickson has seen Red-winged Blackbirds that could not produce red pigments but did produce black: they had pure white patches in their wings. And once she saw a Red-wing that couldn’t produce black pigment, but could produce red: this bird was all white with bright red wing patches.

Photo Study: You Be the Scientist
The robin in the photo is a partial albino. The robin can't tell us why, but we can make guesses to explain why. There seem to be at least three possibilities:
  • The robin’s skin surrounding its beak was damaged after an injury, and the new feathers grew in white. What might the injury have been? Perhaps it slammed repeatedly into a window the year before. (Learn about why robins fly repeatedly into windows.)
  • The robin’s plumage pattern was genetically inherited. The bird always looked this way.
  • The robin’s feathers became white because it is getting old.

Which do you think caused this robin’s white feathers? Think about the following facts:

  1. The white areas on the robin’s face are symmetric, and completely confined to the area around the bird’s beak.
  2. There seem to be no other out-of-place white feathers anywhere on the robin’s body, and the rest of his plumage is dark and healthy-looking.
  3. The robin looks like a very healthy adult male in his prime.

Try this: Journaling question
What might be the reason this robin is a partial albino? Which guess makes the most sense to you? Support your ideas, using facts about the robin’s appearance from the text and photo. Then see what Laura Erickson thinks and how she came to that conclusion.

MORE On Partial Albino Robins: Robins of a Different Feather