Wednesday, April 21, 2010

Leucistic American Robin Photos

Posted by Kirk
One of the fun things about my job as a naturalist is that people send me photos of what they are seeing in their neck of the woods and people do see some wonderful things.

Ann, who lives in Forest Lake, Minnesota, sent these two photos of a rather interesting looking American Robin that frequents her yard. It has a white back, white tail, white wings, white head, etc. yet is clearly an American Robin.

This is known in the scientific realm as a partially leucistic American Robin. What I find fascinating is that I've actually seen a robin with nearly the exact same pattern of leucism before. There are dozens of examples of this particular pattern online. See here, here, here, here and here for just a few examples.

So why isn't this an albino robin? Well, many people would argue that it is. They would use the term "partial albino" but technically albinism is a genetic condition that wipes out the body's ability to create the pigment melanin. Since albinism is genetic it is always systemic, i.e. affecting all of the animal. Ann's photos clearly show that this is not the case.

If this was a true albino, it would also have white legs, white beak, and white breast. It would also have those famous pink albino eyes. None of this is true for this bird. Especially noticeable, the breast is the normal rusty red color of an American Robin.

How do we get a partially white animal then? Enter Leucism. Leucism results from defects in pigment cells. It can affect just one cell or all of the cells on an animal. This means we can get a bird with just one odd white feather or, as in this case, lots of white feathers. We can even get a leucistic bird with all white feathers but normal colored eyes, beak and legs.

For more reading on color aberrations in birds you can download my favorite and oft cited journal article on the topic, Not Every White Bird is an Albino: Sense and Nonsense About Color Aberrations in Birds by Hein van Grouw. Wonderfully, it is available for free download.



Debbie Miller @HooootOwl said...

I live in Illinois and saw two different Luecistic Geese near my home recently. I wasn't sure what they were. Enjoyed this post, thank you.

Kirk said...

Great Debbie. Glad you stopped by. Leucism is fascinating.

Abbie said...

This spring (2012), I saw a partially leucistic American at the Minneapolis Sculpture Garden. The best part about it was by watching this individual over time to get a sense of just territorial and micro-territorial Robins are. You too can probably see this robin with spotty white feathers on the west edge of the Sculpture Garden, between the Spoonbridge & Cherry, Charles Gennevers' Nautilus, and Sol LeWitt's X with Columns.

JMP said...

Just observed a Leucistic American Robin in my backyard. Will try to send you a pic via Twitter if I can find you. Pretty stunning bird b/c of how intermittent the white was.