Genetics Gone Wild – Revisited
Revisiting the topic of genetics we’ll examine a few other gene mutations. All the subjects here were seen over the course of a few days and were part of a large flock of birds stopping in our yard.
First we have the usual suspects. A common grackle, an european starling, a red wing black bird and a miniature bald eagle.
A miniature what? No, that’s not an eagle. Based on the eye color and shape it appears to be a grackle, although in flight it does look a lot like a miniature bald eagle. This color variation is usually a leucistic variation. This is when the bird’s genetics determine that it is unable to make a color that is normally found in its plumage.
The Sibley Guide, found online, describes this much better than I can. Another example of the color variation is seen below.
One of these birds is not like the others. In this case all the center feathers on the tail are pure white while the outer feathers are still normally colored as is the rest of the bird.
Finally here is one with a partial leucistic coloring just on the head.
In all three cases the differently colored birds all had the yellow eye with the black pupil and the beaks all had a similar shape so we’re fairly confident all three are common grackles. What drew our attention to these was the flash of white in an otherwise predominantly dark color flock of birds. I wonder if predators also are able to more easily pick out a bird like this in a flock?
Unlike albinos, these birds do have most of their colors. In a true albino there would be a complete lack of all color.
What's In My Yard 