its not always grey..
we have several kinds.. but i dont know what orginally name itself.. but the colors are..
albino (white).. alot are here..
Black... alot think its bring bad luck.. i dont believe it.. they are great to have them around.. they eat everything even almost sweep off the nuts/acorns off the ground very good... but they dont chew on patio or stuff.. we have few of those black in here..
Red-- few.. but intersting color tho.. its like brick red...
Grey.. but very light ... very common..