Get the odd one in a marten box in the fall,usually in a box near a creek. I caught 3 mink in one day in elevated marten boxes on a 4km spur that ran along a creek.It was in january right during a mid winter thaw.
Mink hunt subnivean here moreso than marten or any other animal.They go under as soon as the powder snow gets about half a foot deep.
The other time they come up(and show up occasionally in a marten box) is in February when the males get to roaming all over.