Just in your description Jeremy I’ll say you have a mole issue. Those Tom Cat grubs are a dandy mole control item but you have to wear gloves and use a clean needle-nosed pliers or hemostat to handle the things or a mole will smell odors from you. I punch a hole thru to the tunnel with a stick, then push the poison grub down with a hemostat or the stick. The trap you’re using is often too shallow to catch a mole. There is a scissors trap that I use on tunnel runs out in the open away from plants and this type of trap catches most of my problem moles. I’ll post a picture of the trap with its box in a bit here. I got the trap at a Tractor Supply store here in Rochester.
Shrews are super active and can eat three times their weight in a day. Everyday. And they’re strictly meat eaters so any for of insect is fair game along with mice. Mice in traps are easy prey for them. Mice are omnivorous and will dine on anything including protein from animals and bugs so in part they are competitors with the shrews. Voles are tunnelers too and resemble mice more than shrews but are strictly vegetarians and love plant roots as well as surface foods the plants provide.
The ground in the begonia bed is super soft and light so shrews can make tunnels right under the surface, similar to a mole, but shrews need constant fresh air so they create small air holes in the tunnels. Mice will frequent those same tunnels that shrews create, hence catching both from one tunnel.
Moles as you know tunnel and shove up the dirt as they push their way forward. Unlike the shrews, moles have blood with extraordinarily high hemoglobin levels and can extract adequate oxygen from the poorer air of their tunnels. Like pocket gophers, moles will actively try to plug holes in their tunnels that allow air movement. Both of these critters are very sensitive to vibration and anything that moves across their hair…think air movement.
Moles are seldom seen out of their tunnel network, which can reach depths of 15 to 18 or more feet deep. The tunnels we see are where they hunt for food. Their living quarters are way down deep. Shrews though, because of an extremely high metabolic rate, have to hunt aggressively and can often be seen scampering across open areas from air hole to air hole or chomping on ants at a hill just like we see mice scooting along going from one place to another.