My favorite scope for fox, coyote, and prairie dogs used to be 6.5-20's.
For p.d.'s, I found myself setting the power ring at 16 for a compromise between field of view & power.
For calling varmints, I found 6.5X a bit much sometimes.
I've settled on 4.5-14 LR with the Varmint Hunters Reticle.
I like them so well I've got over a dozen on different rigs.
Now, if you don't call, and just snipe at them, and/ or your going to do more playing at long range, go to the 6.5-20 or 8.5-25.
I got those, too.