A Detroit black squirrel zips up a mature oak on the East Side of Detroit. The black coat is a color phase that a gray squirrel goes through. There are also red and sometimes albino ones. You don’t find these guys just anywhere, mostly in northern cities. In the country, the black coat is an invitation to predators so this is an urban evolution maybe. This particular oak is not bearing this year so this fellow will have to go down the block for his nuts.