Hi Lucinda
Robbing can be an indicator of something afoul within the colony.If robbing
starts it usually continues until all provisions are depleted and the colony
is totally demoralised.At that point it has been shown that the bees
absconded , whatever is left and the hive is empty. You will also find that
yellow jackets take part in the robbing if present.
This happened to me and the culprit was Tracheal mite infestation in an
otherwise massive colony and with plenty of food.Under thes conditions ,when
bees migrate to other healthy colonies ,they will be infected also.
JDF