We were visiting my parents the other day when Dad said "see my white breasted robin?"Well sure enough there it was doing robin things all over the neighborhood.
I have never seen one before so it was kind of interesting.
I’m not much of a bordwatcher and I have to look up ornithology in the dictionary just to spell it.
How common are color changes in birds?
The American robin is Turdus migratorius. I sh*t you not. I don’t have an answer to you, but I thought I’d share.
brachyrhynchos is an ornithologist. He’ll know.
**
What?!?!? The American robin is named for my late aunt?
brachyrhynchos is an ornithologist. She’ll know.
The American robin is Turdus migratorius.
Y’know, I don’t think I really needed to know that. 
A thousand pardons for the mistake.
Some birds change colors every season. Usually, it’s a moderate variation (e.g., lighter shades) but sometimes the boldest colors only come out during mating season.
Some birds also have color variation with age.
And gender.
Color variations make for an interesting challange for bird watchers.
Thats Nice Phobos
But what about White Breasted Robins? I’ve never seen one before so I doubt that this is the grandpappy of all robins.
Albinism in birds are fairly common (or at least we notice those that are colored differently). And there are several forms, generally attributed to genetic aberrations. But first, a little something about coloration in birds.
Color is derived from two sources: pigments and structure. Many brightly-colored birds, such as warblers, lay pigments down in their feathers, resulting in color we see no matter which way the bird is observed. Others, such as hummingbirds, have feathers with a structure that reflects light so that the color (irridescence) appears when viewed at certain angles. Since both strategies are genetically determined (and is influenced by diet to only a small degree, as in flamingoes, whose pink coloration is derived from the food they eat), mutations can result in colorations not original to the design.
Albinism is the lack of pigmentation, resulting in white feathers. A bird can be totally albino, with pink legs and eyes (the influence of underlying blood vessels) or they can be leucistic, meaning partially or imperfect albinism. This second form may be expressed as a patch of white (such as in your robin) or as a lighter variation of a darker color (black is now gray or brown is now tan). Feathers, legs, skin, bills, toenails can be all affected. When feathers are affected, it is sometimes seen as “balanced” with patches seen at the same place on both sides of the body. (The opposite of albinism is melanism, where more than normal amounts of melanin pigment is layed down, resulting in a darker than normal individual. Down the road in Princeton, NJ is a melanistic population of squirrels. There is also erythrism: more red; and xanthochroism: more yellow variations.)
Not all birds have the same rate of albinism. American Robins (yep, Turdus migratorius) has perhaps the highest rate, but they may be just more visible than other types of birds. Corvids (crows, magpies, jays, and ravens) also have high rates as do House Sparrows (Passer domesticus), certain hawks, and icterids (blackbirds). Amd, as the Princeton squirrels suggest, albinism varies across populations.
I’ve never seen one either…I’d have to check my bird guides.
But what’s up with “that’s nice”?!? Your OP asked “How common are color changes in birds?” I answered. Perhaps you should have phrased it to ask “How common are color changes in Robins?”
Phobos
Sorry about that. I wished I hadn’t been such a smart ASS as soon as I hit Submit. SORRY AGAIN.
brachyrhynchos
I forgot to thank you for the information. I was busy eating crow.
Dads robin has a light gray breast and tan body. I couldn’t see the feet or eyes so I don’t know about that. I think we’ll take a camera with us next time. Any idea about its’ chances of survival to return next year?
Aren’t American Robins actually Thrushes and the European Robins the real things. Or is it the other way around.
Pigeons, at least in Chgo, seem to be abundantly albino
no problem. I often would like a “take back” button next to the “submit” one too.
Pigeons (rock doves) in Chicago, as noted by Markxxx show much greater variation than I have seen in other places. In most other cities I have been to, most of the pigeons are the standard gray body, darker grey head, and iridescent purple/green neck band. Here in the windy city, I would fathom that such pigeons are not the norm, but rather no more prevalent than other color variations. I see as many brown and tan or splotchy grey and white pigeons here as I do the standard coloration, as well as numerous intermediaries between these three major types.
Actually, these are from other folks on the net:
Partial albino robin from Tennessee
Nova Scotian total albino robin
The whole enchilada - normally colored robins and info from Chipper Woods Bird Observatory
So, how long would these guys last in the wild? A number of people suspect that full albinos would not last too long because they would stand out like a sore thumb. Now, there are lots of nearly white birds - Snow Geese, for example, but when you’re one of hundreds in a flock, well, you just don’t stand out. But, an albino of a normally colorful species might be too conspicuous and thus an easy target to zero in on. Partial albinos are another story. Banding studies have shown that they can live for extended periods of time. Middleton banded a partial albino that he recaught 8 years later. And they can apparently reproduce (i.e. be accepted as a robin by other robins) since the albinistic allele is expressed frequently enough for us to observe these differently-colored birds. (Speaking of fighting odds, last year I banded a Black-capped Chickadee. I caught her in a mist-net and she fought like crazy. Her family was in a bush chittering away. The “kicker” was her leg - corkscrewed with the toes fused. But, she was an adult female with a brood patch, meaning she was reproductive. So, even though one might not be optimal, becoming hawkfood or a social outcast is not a foregone conclusion. Cool.)
Phobos, you mentioned age-related color changes. At first I thought you were referring to the fact that some birds take several years to reach adult plumage. Some gulls can take either 3 or 4 years to reach this stage. Now, it appears that it may be possible to associated white feathers in robins with increasing age (an avian version of getting gray). I don’t know how accurate this is, so I’m going to look into this more.
markxxx: You’re right, American Robins are thrushes. The kids are heavily spotted and streaked like Wood, Hermit, and other Thrushes.
justwannanoYou’re welcome. And thank you for giving me an opening to share my favorite crow recipe (I eat it enough myself):
from Larousse Gastronomique - "The recipe is simple. One only has to make, according to the sacred rites, an ordinary good pot-au-feu. On the lid of the pot (the lid is reversed for the purpose) one puts a plucked crow. Then after 5 or 6 hours of gentle cooking one ‘…throws the crow in the fire and enjoys the pot-au-feu…’ "