If they are "surface stained" Then part of the answer may be because I have noticed a tendancy for individual bucks to rub a certain species of tree.
Not sure if that's the same thing I read before, but I've seen all that info in the past. I buy into all of it and think it primarily has to do with the shedding of velvet.
Pretty neat stuff! It is interesting how certain regions seem to produce different color characteristics.In Idaho the majority of the bucks I have killed have had a reddish brown tint to them although I have taken a couple that are very white.In New York in my area I have seen a variety of coloration,grey,very white,yellowish all from similar habitat. I shot a buck three seasons ago out west that has dark chocolate colored antlers,I realy like that coloration.I was concerned they would lighten up as they dried but they have not. I would tend to think that it is primarily genetic because of different coloration coming from the same area's.Even the oxidation that comes from the growth and velvet shedding process I would think would be influenced by that individual animals body chemistry.When you have every inch of antler the exact same color I don't believe that could be indicative of rubbing on a particular tree species,you wold never acheive the uniformity of color.Great topic!
there4 is a really cool article about antler color in the lastest issue of Deer & Deer Hunting. It was pretty interesting to read.