of a Different Feather
one of the most familiar birds in America, famous for their red breasts;
they also have gray backs. Male and female robins both have the same color
combination, although the color is richer in males. But some robins have
white patches on their bodies. Some have a white breast instead of red.
Some have a white instead of gray back, and a few are pure white! These
are called albino robins.
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. Some
animals make normal pigments in parts of their bodies and no pigments
others. These are called partial albinos. Which robins below are
albinos? Partial albinos?
Pigments do more for feathers than simply give them color. They also make
the feathers stronger. That is one of the reasons that the people who
first domesticated ducks preferred white ones; they were easier to pluck.
In the wild, colored feathers last longer without fraying than white ones
do. Pigments in the irises and retinas of our eyes protect us from light.
Without these pigments, people with albinism often must wear sunglasses.
Birds and other wild animals can't wear sunglasses, and many of them eventually
go blind. Fortunately, most albino robins are only partial albinos. With
pigments in their eyes, they have better vision and can sometimes live
as long as robins with normal colors.
Robins: Not So Uncommon
For some reason, albinism and partial albinism have been recorded in robins
more than any other wild bird species. One study found that 8.22% of all
albino wild birds found in North America were robins. But only about one
robin in 30,000 is an albino or partial albino. Most records of robins
with albinism are only partial albinos, which of course live longer than
a Girard, IL, observer watched albino robin chicks in a nesting box in
her own yard. She writes: "Last year Mama Robin raised two sets
of nestlings, in the same nest, and there was an albino in each set.
nest was easily viewed from our breakfast room window. Our granddaughter
first noticed the first albino, telling us there was a baby chick on
limb of the tree. Mama continued to feed it, but it didn't come down
from the tree as the others did. It stayed on the branch for three days,
one early morning it was gone. I hope it flew away. We were surprised
to see an albino in her second set of nestlings, but we never saw either
of them in our yard after they fledged."
Scientists — and observers like us — may
be more likely to find albino robins than albinos of other species
for several reasons.
People see more robins than most other species, so even if albinism
were totally random, we'd be more likely to see albino robins than
birds. Robins live in people's yards, where they are conspicuous
in the open, and don't really need to blend into their backgrounds,
so maybe albinos can survive better than other species that need
better. Robins don't migrate as far as neotropical migrants (hummingbirds,
orioles, and others) do, so weakened flight feathers may not be
as critical. And robins may make
choices using song and behavior more than plumage; in
that case, albino robins would have a better chance of reproducing
than albinos of some other species.
Visualizing and Journaling Activities
being a newly-hatched albino baby robin. You don't have a mirror. Like
other birds, you probably don't think a lot about how you look, but
you certainly notice how other birds react to you! Do you think you
would ever realize that you look different from your brothers and sisters?
How might you make that realization?
about some of the special problems albino robins might face in their
lives. Think about their vision, their interactions with other robins,
and their visability to predators. Do you think it would be easier or
harder for a robin to be "different" from its family and neighbors
than for a human to be "different"?
More. See Who is That
Masked Robin? Partial Albinism
Science Education Standards
- Each animal
has different structures that serve different functions in growth, survival,
- Many characteristics
of an organism are inherited from the parents, but others result from
an individual's interactions with the environment.