London: For pigeons, it seems, leadership is largely a question of speed.
Researchers compared pigeons' relative influence over flock direction to their solo flight characteristics. The studies showed that a pigeon's degree of leadership could be predicted by its speed in earlier flights.
"This changes our understanding of how the flocks are structured and why flocks of this species have consistent leadership hierarchies," said Dora Biro of the University of Oxford in London.
The latest GPS loggers allow the researchers to track not only the birds' overall routes, but also the sub-second time delays with which they react to each other while flying as a flock.
"We can control the composition of the flocks and the starting points for their homeward journeys," said Benjamin Pettit, first author of the study.
When the researchers tested the birds individually after a series of flock flights, they found that leaders had learned straighter homing routes than followers.
The new findings offer an elegantly simple explanation for the phenomenon of leadership in birds, with important implications for how spatial knowledge is generated and retained in navigating flocks.
"We also have a good understanding of their individual spatial cognition, in particular how their homing routes develop over repeated flights in the same area," Pettit noted.
"Some birds are naturally faster and consistently get to the front, where they end up doing more of the navigation, which means on future flights they know the way better," Biro added.
"You can compare this to a 'passenger-driver' like effect: drivers in a car have to pay attention while passengers are often unable to recall the route they were driven along, especially if they remained passive in the navigation process," Biro explained.
A very simple, self-organising mechanism--such as that based on variation in speed--is sufficient for leadership to arise.
The study was published in the Cell Press journal Current Biology recently.