5.6. Flight activity
1. Bee flight activity can be monitored visually at hive entrances to gain a relative measure of colony foraging effort. To control for between-colony variation due to time of day, the investigator should: 1. limit observations to days and time of day with good flight conditions; 2. randomize the numeric order in which colonies are measured; 3. measure all colonies within a relatively narrow window of hours, and; 4. limit colony observations to the same time window over successive days.
2. Two observers sit to the side of a colony, each positioned well enough to the side to avoid obstructing the flight of the bees. Each observer has a hand-held counting device and one keeps time.
3. For one 15-min counting episode, each observer counts and records the number of bees exiting the colony (but see below). Exiting bees are simpler to count because returning foragers land with less predictability; some directly into the entrance, others onto the front of the hive.
4. The mean of the two observers is derived and the data reported as exiting foragers per min.
5. Investigators may want to focus on returning, instead of exiting foragers, especially if pollen foraging is a parameter of interest. In these cases observers need to count foragers returning with, and without, corbicular pollen loads in order to derive proportion of foragers collecting pollen.