Two days after the last catch, these popped up in the lawn in a different part of the yard. 
So, I was thinking I was getting the upper hand after getting #7, but since I previously hadn't trapped any for over a year, there are probably several more. Extension publications say that 3 to 5 moles per acre is considered a high population, but other articles I have read have said that populations after the yearly litter is produced can go up to 16 per acre under ideal circumstances.
I think there must be at least 3 different mole families in different parts of my .9 acre lot. Activity has disappeared in 2 of the 3 areas, but these molehills indicate a deeper network of runs in the vicinity. These will be harder to locate, but it will be worth the effort, because these will be well-traveled runs where traps can be successfully set.
I'll try using a long, stiff wire to probe the ground nearby. The runs may be 4 to 12 or more inches deep. The wire will give when it passes through the run. Visible mole activity often wanes during a dry summer, making trapping more difficult since you have to find an active tunnel, whether a shallow surface run or a deeper, more permanent tunnel.
