London, Apr 23 : Researchers at the Federal University of Rio de Janeiro in Brazil have found out why migratory birds like geese fly in a V formation.

With the help of a computer model they have combined two competing theories.

The first suggests that the formation has an aerodynamic advantage - each bird creates an upwash behind its wing tips, giving those following it an extra lift. The second holds that flying in a slightly skewed position relative to the bird in front allows for unimpaired vision.

As part of the study, Valmir Barbosa and Andre Nathan created computer models of flocks of between 15 and 35 birds, taking both theories into account. Each bird was allowed to seek out the one nearest to it, and to position itself so that its view was not blocked. It could then adjust its position to take advantage of any improved aerodynamics.

Findings revealed both theories to hold true.

According to Barbosa, previous computer models that did not take both into account were unable to reproduce V-formations.

“But we have found that these formations occur regardless of how the birds are positioned initially,” New Scientist quoted him as saying.

Findings revealed that the artificial birds also settled into other patterns seen in nature, such as W-formations.

“This is an appealing instance of how complexity emerges from simple rules,” Barbosa added. (ANI)