The established garden plot is roughly 25 feet by 12 feet, and our intentions are to expand this plot by a good section every year. This year, however, we will limit our garden production to the established plot since we have lots of things vying for our attention (like, say, all those boxes that have yet to unpack themselves - what's up with that?).
This is an example of the few holes present in the garden (keys are included for scale). There's less than a handful of these in the actual garden space, but there's a couple dozen just like them scattered throughout the yard. In general, the hole is roughly two inches in diameter.
A quicky Google search revealed the error of my knowledge - moles are small! Like, rat-size small! I had no idea. According to the University of Kansas Field Station website (from which the below photo originated), what we most likely have are eastern moles. They are mostly solitary (thank goodness, I had envisioned a city of moles under our property, vis a vis The Secret of NIMH) and primarily eat grubs and earthworms.
Up to now the only major threats I had to protect our garden from were squirrels (acquired a dog that scared off the squirrels) and the dog (acquired a garden fence that kept the dog out). I'm not battle ready when it comes to "varmints."
Apparently, there's a multitude of really nasty and questionably effective approaches to dealing with moles (pouring boiling water down the tunnels, claw traps at tunnel openings, poison), but I'm not willing to use such options due to their inhumane aspects and the fact that children and pets will be using the yard as well. This basically leaves two options...coating their tunnel openings with Castor oil (it gets on their fur, tastes bad and might give them an upset stomach which, supposedly, makes them move on) and/or getting rid of their food source.
Either way we better get crakin' on this problem, since we still have to address the deer and rabbit interlopers as well.