As I've mentioned before, I once planted 150 tulip bulbs and not a single one came up the following spring, but voles were seen in my yard, laying on their backs and patting their stomachs.
I asked Holper about the difference between moles and voles.
"A vole is a rodent and a mole is an insectivore," he told me. "A vole is a heavy vegetation eater - bulbs, seeds, hostas -- and they are the most prolific. A female can be pregnant within 24 hours of a litter and can produce 200 babies a year.
"They can be serious when they hit a garden."
"A vole does damage to what you paid to plant," he said. "A mole messes with people's minds. After you have tried so many things to kill it, it becomes a personal issue. You start thinking about explosives."
His trap works, he says. "Once you know how to do it, you actually look forward to the next mole."