Once the snow comes the reds are suckers for mouth calling...With not light and twilight conditions over snow...You could lure them into about 100 yards to point blank by doing woodpecker, fieldmice,...um they like real high pitched sounds.. Get yourself a Verminator....Black Tweedy. Bite up and down on the reed about 1/8- 1/4 inch from the end, blow into the call and shake it back in forth in your mouth all at the same time.
Take your finger and rub it over up and down and around the front of the barrel while your doing this..
Let your electronic calls just rip for a long period with a woodpecker sound..No interuptions..
If your a shotfunner... Put the call down and walk 75 to 100 yards down wind of the speaker... Post 30 yards to the side of the main sound beam. Could be your calling them in and they are holding up on you..They are good for that..Make sure you keep your red lens light on at all times and watch the down wind side of the speaker real good..