The unfortunate Colony 11 has been robbed today by Colony 1. I think that I've stemmed the robbing but I will have to move Colony 11 for the second time tonight.
The action began around lunchtime today. There was a big increase in activity at the entrance of Colony 11 and Colony 1. There were bees flying widely around my garden; their flight paths were hard to follow. There were bees behind the hive and under it too. They crawled under the base board. I thought this was strange but didn't see immediately that it was robbing.
All through this afternoon there has been lots of activity around Colony 11. There have also been crawling bees -- some of them tired; some appearing to have paralysed wings; one missing legs. I tried shielding the hive entrance with a wooden sheet (just visible in the photograph) but this didn't appear to stop the robbing. Eventually I stopped up most of the entrance. I've seen bees squeezing through the remaining gap. I haven't see whether this has stopped the robbing.