A colony of bees varies in its aggressiveness depending on a number of factors. Colonies that have gone queen-less, have been pestered by animals, or are exposed to high levels of noise may be skittish and temperamental. Colonies at the end of winter, in the midst of a nectar flow, or in the act of swarming may seem unnaturally calm. These fluctuations in behaviour can be helpful clues as to what is taking place inside the hive.