On warm winter days, I visit the hives to check their overall well-being. On this day, it was 50 degrees with no wind. I saw my homemade hive — the entrance reducer was on the ground.
I have another hive where this happened three times, also on a homemade bottom board. The issue here is tolerances — a standard entrance reducer from a factory will not fit, so I cut a piece of random wood — maybe a top bar from a frame, a piece of parting stop, whatever I found laying around the garage — and set it in place. The problem? The remaining hole is large enough for critters to access, remove the homemade reducer, and invade the hive.
The hive in the photo had a mouse at one point. I could see the nest when looking down from the top box. I couldn’t remove all the nest, but got about half of it removed, just so I could see if it was currently living there. I think it was. It also ate a good chunk of comb from the outermost frame. My bees don’t need stress from a mouse in their house, so I used my staple gun to attach the reducer as best I could. I will be measuring for a better fitting (and truly designed) reducer as a replacement.