If he's a mink he has to eat constantly, as he doesn't carry an excess of body fat. Chances are, if it is a mink, it is miles down the creekbed along his journey. Otters will be similarly nomadic and won't hang out either. Actually, otters run slightly larger patterns. Both can be patterned.
A mink's need to travel is the same reason that you can call in or trap a coyote when it gets below about 20 degrees, but you will only rarely find a coon in your trap at the same temperature. Mink and coyote require food regardless of conditions; coons have fat and hole up on the really bad days.
While I have a significant number of pelts in my reloading room to claim otherwise, I may be wrong. My comments are just based on time spent trying to get them to put a foot on a 2 inch pan.