Those darn mice! They licked the bait completely off that trigger without springing the trap! How can that happen? Is the trap really that insensitive? Or… did we fail to note the other pests in the area? Ants, such as these pavement ants (Tetramorium caespitum), are more than capable of stealing the bait cleanly off the trap without tripping it. There are a number of other species that can also do this.
When you find a trap or traps that have all the bait gone, whether they are still set or sprung, consider a non-target pest. Ants are the most common, but other insects may be involved. A thorough inspection — and perhaps even an application — may be necessary to protect your attractants.
You may also try different attractants. Mice can be enticed onto traps with cotton balls or packing peanuts which, to date, have not been known to be the targets of ant foraging.
Contributor Mark Sheperdigian can be reached at firstname.lastname@example.org.