Black Nutsy

I always suspected that we had more than one Nutsy. Now that this chap appeared on the bird feeder this morning, I know we have at least two. Nutsy thinks he lives here. He certainly takes his meals here. As soon as all the snow goes, the balcony will be squirrel-proofed. Hear that Nutsy? Squirrel-proofed.

According to Wikipedia, the black squirrel is a melanistic subgroup of the eastern grey squirrel, and they are apparently quite common here in the midwest (first one that I've noticed). Black squirrels have either one or two copies of a mutant gene - those with two copies are jet black, so I'm guessing that Nutsy here is a heterozygote (1 copy). The article goes on to say that the black variant was the commoner type in North America prior to the arrival of the Europeans. If this is the case, then it's the grey squirrel that is the true mutant.