is That Masked Robin?
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:
are the chemicals in our bodies that give us our colors.
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.
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
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.
Causes White Feathers on Birds That Are Normally Colorful?
birds suffer serious injuries, sometimes replacement feathers
grow in pure white. These injuries could include such things as:
feathers after narrowly escaping from a hawk or cat;
repeatedly into a window; or,
recovering from a horrible case of lice or mites.
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.
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
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.
robin’s feathers became white because it is getting old.
do you think caused this robin’s white feathers? Think
about the following facts:
white areas on the robin’s face are symmetric, and
completely confined to the area around the bird’s beak.
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.
robin looks like a very healthy adult male in his prime.
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.
On Partial Albino Robins: Robins
of a Different Feather