If your hive suddenly loses a dramatic amount of weight – there could be a number of reasons, but the most common reason for this is robbing.
How to detect robbing?
A weak colony will generally have lower flight noise and hive activity levels than a strong colony. A sudden increase in daytime flight activity in a weak colony combined with very low night time activity could be an indicator that it is being robbed of its honey.
Plot the weight of your graph and add the peak flight noise to it. An example of this can be seen in the graph below. This colony lost over 10kg in less than 2 days. When you examine the flight noise, you can deduct that a lot of bees must have entered the hive….