Each year we have a robbing problem with my home apiary. Typically, nucs or smaller colonies are targeted. This year I moved the nucs to another location early. We were very conservative with our harvest and the other six colonies at this location had plenty of stores.
The closet managed hives I know of are at least one mile away (as the bee flies). The robbers targeted a four eight frame medium early split hive. The bottom three boxes where loaded with bees. Very healthy. The top box was all honey. This was at the start of the GR bloom so I have no doubt they would have backfilled to be ready for winter.
I reduced the entrance down, but did not install a robber screen. The hive eventually absconded. Any thoughts as to why a strong colony like this would be targeted?