This is my first year in beekeeping, and I need some advice: Today one of my hives was very agitated, lots of flying around out front, and bees were swarming into the entrances with a certain frenzied quality. I thought maybe it was orientation flights, but there was a more agitated quality to the bees behavior. Not a lot of fighting out front so I don't know if it was robbing. There were a fair number of drones on the ground outside the hive , crawling but not flying back to the hive. Then late in the day, large numbers of bees clustered under the hive, by the bottom screen. A lot of them looked like they were shaking or vibrating. When I went back to look at about 7 pm, there were several hundreds of dead bees carpeting the cinder blocks on which the hive rests and also dead bees on the ground in front of the hive. I will look in tomorrow to see if there is a shortage of honey (two weeks ago, half the frames in the upper brood chamber were full of capped honey, and I'd removed one full super.) Anyone have thoughts on the various possibilities that might be have caused the die off, and what to look for in the hive?