London, April 8 (ANI): Pigeons rapidly shift direction during flight in response to cues from the leading members of their group, a new study has found.
Scientists made the discovery with the help of newly introduced Global Positioning System (GPS) devices that can collect data at a high rate: five times per second.
"It is the first study demonstrating hierarchical decision-making in a group of free-flying birds," says Tamas Vicsek, a biophysicist at Eotvos Lorand University in Budapest who led the study.
Vicsek's team strapped lightweight GPS devices to individual pigeons and tracked flocks of up to 10 birds during free flights lasting around 12 minutes and 15-kilometre homing flights.
In total, the GPS logged 32 hours of data and captured 15 group flights. The researchers couldn't pinpoint individuals' exact positions within a flock, but were able to accurately compare birds' directions of motion.
Within flocks, the authors looked first at the behaviour of pairs of birds. For each possible pairing, the team identified a leader the bird that changed direction first - and a follower, which copied the leader's motion. Followers reacted very quickly, within a fraction of a second.
Next, the researchers built a network of relationships among birds in the group during each flight.
They discovered a robust pecking order: birds higher up the ranks had more influence over the group's movements, and each individual's level of influence was consistent across specific free and homing flights.
However, this influence was not always consistent between flights, with some rearrangement occurring among birds at the head of the flock.
Vicsek speculates that this may have occurred because an original leader had tired.
Although pigeons have an almost 340 degree field of view, the researchers found that the birds at the front of a flock tended to make the navigational decisions.
Moreover, birds responded more readily to a leader's movements if the leader was on their left side.
The study has been published in Nature. (ANI)