How birds of a feather are able to flock together... they are democratic

[Donna]

Scientists have discovered how huge flocks of birds decide when to change direction in mid flight... they use a kind of 'democratic hierarchy.'

The team from Britain and Hungary strapped tiny global position systems (GPS) to pigeons to work out how they operated as a well-ordered group rather than chaotic individuals.

The researchers recorded the flight paths of individual birds and then analysed interactions between them.
They found that pigeon flocks use a flexible system of leadership where almost every member plays a part, but high-ranking birds have more power.

The findings, published in the journal Nature yesterday, could help unravel the collective behaviour and decision-making processes of other groups of animals, including humans.
To conduct their study, the researchers fitted miniature GPS loggers weighing less than one ounce into custom-made backpacks carried by flocks of up to 10 homing pigeons.

The devices allowed scientists to analyse spatial and temporal relationships between birds and the movement decisions they made at the scale of a fraction of a second.

'These hierarchies are flexible in the sense that the leading role of any given bird can vary over time,' said Biro.

'This dynamic, flexible segregation of individuals into leaders and followers - where even the lower-ranking members' opinions can make a contribution - may represent a particularly efficient form of decision-making.'

The scientists said more studies could help explain how such a sophisticated leadership system is able to give evolutionary advantage to individuals, compared with strategy based on a single leader or one where all members play an equal part.