Why do bees rob another hive? Robber bees will rob another hive if the hive is weak or if there are drought conditions and there is a lack of nectar sources. Normally a hive that is being robbed is a weaker hive or is low in numbers and they are not able to fully defend themselves. Normally you will only see robbing in the fall time, going into winter when bees, yellow jackets and others are all looking for that last source of food before winter sets in. Yet with the drought conditions and warmer temperatures we are now experiencing, robbing is also happening in the spring and late summer as well.