Spotted some bees being wrestled off the landing boards on my hives today, somewhat larger and blacker than mine (with gray stripes instead of orange, too). Only one or two, and the girls were effectively running them off, but I put my entrance reducers on anyway -- gonna be cold and wet for a couple days and I'd prefer to head off a robbing frenzy.

I accused my brother of letting his bees steal my honey, since his bees look a great deal like the ones I saw, but I don't really think they are, he's at least three miles away and there is lots of forage at the moment. Could be though.

So we put an entrance reducer on his hive too, after I made a couple. I like closing them down in the winter anyway, and it's likely getting on mouse season here too.