the golpher traps out west used the tunnel trick too
of course tho it was a belly squeezer bar trap but very effective
but the way they fooled the gopher was to make a small round hole
in the back side of the trap [ o ] so when they look ahead it
APPEARS as though the tunnel exit is up aways and then they'd stumble/bump
into the spring lever....
so R9's method is tried and true
dead on