I got my first experience with the damage a mouse can cause on a colony of bees this year, It was a lesson I won't soon forget! A local beekeeper passed away recently and the family asked Jeff to sell off his excess equipment and remove a couple remaining hives of bees that had not been touched since last October. First the bees were relocated because family members said they were allergic. Second we were very busy with packages, nucs, removals and swarms. Inspection of those hives would have to wait.
Jeff and I were working some nucs one afternoon and he got a call they his hive was swarming at one of his bee yards. Since we were very close we took off quickly hoping to capture the swarm or figure out what was really going on in that apiary. When we got there the hive had swarmed and we could not find where the swarm had gone. It was time for some preventative maintenance so we started going through the other hives. We opened up the "mouse" hive and found a deep filled with nice full frames of honey and some good brood frames also, but with no sign of the queen we went to examine the lower deep.This was where all the carnage was in the hive. Piles of mouse nesting material, hair, grass and feces were everywhere. Holes were cut through the Duragilt wax foundation and many of the frames were chewed through completely. It was a horrible mess with bees crawling through the filth to bring in the valuable pollen and nectar.
Looking down in the deep Jeff found the queen and we rescued her to a temporary queen cage as we took the hive apart one frame at a time and dismantled it completely, finally cleaning it out with soapy water. Adding fresh and some fixed frames we began putting the hive back together. 
We had to take some of the honey out of the hive and checker-boarded the rest of the frames in each deep super but keeping the brood frames together with the nurse bees. This queen was a survivor and we wanted to keep her genetics going so we released her back into the hive.
In the Gallery below you can see the damage a mouse can do to a colony over winter and how lucky this colony was to survive. Also below are two videos: 1. a video showing you how to make your own inexpensive mouse guard as seen on the photos in this article and 2. a video showing the last hive inspection of the "mouse" hive. How do you think that colony and queen are doing today?
Click Image to see the Mouse Damage Gallery:
Mouse damaged hive a few weeks later hive inspection video:
Inexpensive DIY Mouse guard: