Birds take it in turns to lead, say scientists
Scientists have worked out how flocking birds solve what they have termed the "social dilemma" of who leads the flock.
The researchers, from the UK, Germany and Austria, studied the northern bald ibis, tracking how they - like so many large birds - fly in a V formation.
They found that birds took it in turns to take the very energy-depleting lead.
This allowed every bird to take advantage of extra lift produced by the wings of the bird in front.
The findings are published in the Proceedings of the National Academy of Sciences.
Victoria Gill reports.