hard to tell. you need to look at the track to determine if its buck or doe. If its in the snow, look for drag marks in the snow and how wide the tracks are. A bucks has a wider stance than a doe, because of his massive chest, where a doe has a more narrow track. You should have stalked him and shot him in his bed, i love tracking in the snow, very rewarding to kill a deer in its bed chewing cud.