Birds fly to a favourite side

By Erin Frick March 11, 2014
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Birds have an innate preference for flying left or right, says a new study.

BIRDS HAVE AN INNATE preference for flying right or left, even if the path is more difficult, a new study shows.

A team of Australian researchers trained budgerigars (Melopsittacus undulatus) to fly through a tunnel in which they placed a dividing barrier, forcing the birds to choose a side to pass through. They adjusted the barrier throughout the study, so that the widths of the left and right passageways varied.

When one side was much wider than the other, most birds chose to fly through the easier gap. But when the two openings were of an equal or very similar width, some birds were consistently attracted to either the right or the left opening, regardless of whether it was the wider option.

“By having a natural mechanism where populations of birds are predisposed to choosing different flight paths around obstacles, an entire flock could avoid situations where they block each other, slow down, lose time and expend more energy,” says Dr Mandyam Srinivasan from the Queensland Brain Institute at the University of Queensland.

Mandyam’s previous research into budgies showed they fly through narrow spaces by comparing how fast their surroundings go past each eye.

Some birds are right-winged

The researchers found the right/left preference varied on an individual basis, which is unexpected. Consider handedness in humans. An overwhelming majority of people are right-handed, making this bias common throughout the entire species. The same would be expected of other species, and for birds, this would reveal itself in their flight path preference.

Individual flight preference would be particularly beneficial to flocks travelling through complex environments where obstacles may hinder quick passage through the area. If all of the individuals in a particular bird species tended to fly to the right, the openings on this favoured side would become blocked while viable openings to the opposite side would go unused, the researchers say.

When the flight path preferences of individual birds are evenly distributed throughout a population, this reduces collision while facilitating quick passage through a cluttered area.

This individual bias may also help the budgerigars’ ability to escape predators. If a species isn’t predictable in favouring one direction over another, birds of prey are less likely to accurately track individuals in a flock.

Bird flight preference could transfer to robots

Mandyam says this bias could also inspire future designs of robotic aircraft to improve interactions with other airborne objects. “While this is still quite theoretical, it may be possible to implement a system of self-organising rules in a fleet of aircraft and arrange for the aircraft to respond to individualised biases,” he says.