Bat and Mouse Identification and Removal
Ingham County, Michigan
A new client in Okemos, Michigan called concerned over noises they heard in their attic and walls. The noise that was described was light scratching and rustling. Typically, in Michigan this means bats or mice (or both) when it comes to nuisance animals inside of structures. We begin with a thorough inspection to identify which species is harboring inside the home, then identify the active entry points, and finally identify any secondary possible entry points. From there, we build a detailed game plan on removing the offending animals from inside the structure.
We inspected both the interior and exterior of the home. Immediately upon entering the attic, we identified two separate culprits: bats and mice. Their droppings were left behind, and to the untrained eye, look almost identical. However, there is one surefire way to know exactly which is species it is: we playfully call it the “Crush Test.” Take an object that is not your barehand, such as a pocketknife, and simply try to crush the dropping. If it is from a bat, it will crumble into powder. Bats in Michigan eat insects primarily and excrete the exoskeletons of the insects. The insect exoskeletons are what crush so easily and turn to powder. Mice, on the other, have a varied diet and their droppings will simply squish flat, or if old, will be rock hard.
Now that we know what animals we are dealing with, we inspect the exterior for their entry points into the home. All homes that have roof returns have construction gaps left behind from the original roofing and siding of the home (See Figure 3). These are most common areas for all nuisance animals to enter, whether it is raccoons, squirrels, bats, or mice. This is common on new homes, old homes, small homes, and large homes.
The photo below shows the size of the opening in the roof return which easily allows bats and mice inside the attic and ultimately into the wall voids and even into the living space. There are bat droppings spilling out of the roof return which is also shown in the photo.
The photo below shows another open roof return with a bat resting just inside the opening.
Our solution is to seal all areas that mice and bats can enter the home. For the active areas that bats are using, we installed a simple and temporary bat one-way door that allows the bats to leave, but not re-enter. We will seal all other possible openings, even if they are not currently used, so as to not shift the wildlife pressure from one side of the home to another. The bats need to leave daily to eat and drink so they let themselves out but then cannot get back into the home. After roughly a week or two we remove the one-way doors and the final areas are sealed up.