I visited my out apiary over the weekend and found that one of my colonies, colony ummm, has died. Colony Ummm? Unfortunately I need to cross check my records to work out which one has died. I really ought to keep better records
The cause appears to be insufficient strength going into winter. The dead bees remaining in the hive were only enough to form a cluster about 10cm diameter, split across 4 sides of frame. When the cold started they couldn't move to neighbouring frames to access the stores there. I had left a super on top with stores which weren't touched. I had also left in the Queen excluder, which probably didn't help. At the top of the super was a wasp body, suggesting that there had been some robbing before winter killed the wasps.
The dead bee bodies were soft, so I think that they had died very recently. Maybe some were alive, but in a way which prevented them being saved. I shut the lid.
I removed the super indoors, and moved the hive around the corner. When the weather is warm enough I hope that the other bees will rob it out without causing a robbing storm.
Update: after reviewing the list of colonies I think that it was colony 18