Having arrived in Sweden early on last Sunday morning, I checked to see if bees were flying later in the day. Of the two entrances, only one had bees flying. I went into the barn and opened up the one that didn't have flying bees to find a dead colony. There was a mouse nest and a huge mess of detritus all over the screen bottom. I thought by having the entrances through the walls of the barn that mice wouldn't be able to enter. Next winter prep I will fit mouse guards. I put the mess down to the mouse but decided to do a comprehensive check on the surviving hive at the first opportunity. I managed to do it yesterday and found almost as much mess in the surviving hive too. No sign of mice but the 6 month period of not being able to clean underneath and the fact that bees cannot clean the bottom themselves with a screened bottom has made me realize that I need to fit solid bottoms on my hives. I scraped half an inch thick gooey mess of horrible gunk off both the underside and top of the screen. The bees were fewer in number than when I left them in October and there was only one frame of sealed brood. I managed to correct some comb problems. There were a lot of attachments and I cut away some of the string that I had tied the comb onto the top bars. One comb that I was cutting side attachments was full of honey and fell off the top bar. I lifted this out and put in new top bars with starter strips. These bees had plenty of stores and were bringing in pollen. I believe these bees may not be as hygienic as my Spanish bees but I am now worried about the hives in Spain with screen bottoms will have similar problems when I return later in the year.
For a minimum disturbance management system that I am now employing, screened bottoms cause more problems than their worth in my opinion. Bees will keep a solid floor clean in my experience. I cleaned out the dead out hive today and removed the screen floor. I will fit a solid floor before next occupation.