Many open plastic reed mouth calls like say the Tally-Ho (my favorite) can make any rabbit/hare scream you want just by moving where you apply pressure on the reed and using your vocal chords to add some coarseness.I would suggest trying right after there's some fresh snow on the ground.Set up in a cross wind position rather than wind in your face.If nothing comes scout all around your location out to about 60-70yds to see if they slipped down wind or maybe caught some movement.Don't underestimate them.Coyote's are very smart.