4.1.4. Colony foraging rate
A colony’s foraging rate refers to the number of foraging trips a colony makes during a day. Generally the more foraging trips bees from a colony make to a crop, the more effective the colony will be at pollinating the crop. The number of bees foraging from a colony can be estimated by counting bees entering the hive (Baker and Jay, 1974). This is usually easier than counting bees leaving a hive as returning foragers approach more slowly. When counting the number of returning bees over a set length of time it is important to do this without disturbing the returning bees. The presence of an observer at the front of a hive may confuse bees and delay their return. This can be avoided by using a hide that can be left in front of the hive. Alternatively, a video camera will be less obtrusive and can be left in position for the bees to become accustomed to it. Video has the advantage that allows the action to be observed in slow motion. The data are reported as returning bees per minute.
Depending on the questions being answered the physical counts or video data may need to be backed up with samples of returning bees. Honey bees observed returning with pollen must have been foraging, however honey bees returning without pollen might be nectar foragers or bees going on orientation flights. Returning bees can be captured by blocking the hive entrance and allowing the returning bees to collect on the outside. The bees without pollen can then be captured. Dissecting the bees and measuring their crop weight will differentiate bees that were on orientation flights from bees that were foraging for nectar.