Animals travelling together often disagree on the best direction, so if they want to stay together they have to decide how to come to an agreement. They obviously have to do so without words. Theory suggests that if they don’t disagree too much they will do the average of their preferred directions, but if they disagree a lot then one individual will keep to their preferred direction and the other will follow, or the group will split.
By attaching GPS loggers to pigeons, this study was able to track the complete flight path of pairs of pigeons over distances from 5.3-10.7km. Pigeons learnt slightly different routes home when flying solitary and were then paired up. As predicted by the theory, when the solitary routes were closer, the pairs flew a route that was an average of the two routes. When the distance between the solitary routes was above a certain distance, pairs followed the solitary route of one individual (the leader). Pairs that compromised tended to have more efficient (shorter) routes than the solitary routes. The leader was not the same individual every time, and was not the individual with the most efficient
Animals follow simple rules for making group decisions. If the conflict between their preferred decision and the decision of group mates is not too different they will compromise. If it is very different they will stick to their own decision. Whether the group stays together depends on the importance of being in a group (e.g. safety in numbers from predation). It is difficult for animals to communicate how good their knowledge if, so sometimes the leader is not the best choice of leader.
Posted by: AndrewDHigginson Posted Fri Nov 10 2017