Joe according to what I've read about black squirrels in Michigan they're actually an offshoot of a gray squirrel
That is a beautiful color. Reading on wiki indicates it is a variation of the black melanistic squirrel: "As a rare mutation of both the eastern gray and fox squirrel, individual black squirrels can exist wherever gray or fox squirrels live. Among eastern squirrels, gray mating pairs cannot produce black offspring. Gray squirrels have two copies of a normal pigment gene and black squirrels have either one or two copies of a mutant pigment gene. If a black squirrel has two copies of the mutant gene it will be jet black. If it has one copy of a mutant gene and one normal gene it will be brown-black. In areas with high concentrations of black squirrels, litters of mixed-color individuals are common."