We have a heard of black white tails on one place and there are several with in-between shades. I don't think they are melanistic just a recessive gene or something. Saw a pretty good eight point that would have made an interesting mount, but let it walk to spread it's genes, which it apparently it did as I saw another young black eight point about 2 years later.
In West Texas some locations have a higher incidence of White Tail/Mule deer crosses. These deer will have a dark tail like the other fawn. It would be really rare to have both the dark or melanistic genetics and white tail genes too, but it is not impossible.
