Budgies reveal the rule that means birds never collide in flight

Birds have in-built air traffic control

FLPA/Alamy Stock Photo

By Alice Klein

How do birds avoid crashing into each other when approaching head-on? They have an in-built preference for veering right.

The finding may contribute to the design of better anti-crash systems in autonomous drones.

Mandyam Srinivasan at the University of Queensland, Australia, and his colleagues uncovered the simple trick when filming pairs of budgerigars flying towards each other in a narrow tunnel (see video, below).

During more than 100 tests, the birds moved to each other’s left hand side in 84 per cent of cases, and zero crashes were observed.

The budgerigars also tended to fly past each other at different heights, which prevented mid-air collisions on the rare occasions that one of the birds veered left.

Group hierarchy may dictate which bird moves up and which moves down, Srinivasan says. “It looks like the dominant birds prefer to go lower,” he says. “Maybe it’s more energy efficient and easier to go lower than higher, so the non-dominant bird is forced to gain altitude.”

Lessons for drones

These crash-avoidance strategies have evolved over 150 million years in birds and can provide inspiration for anti-collision systems in drones, says Srinivasan.

Drones currently use simple proximity sensors to avoid hitting other objects, but they are not sophisticated enough to communicate with each other. Once better sensing technology becomes available, pre-programming all drones to veer right when they encounter one another may be a straightforward strategy to reduce collisions, says Srinivasan.

Height coordination is trickier, but could potentially be achieved by assigning numbers to each drone, Srinivasan says. Upon approach, the rule may be that the drone with the higher number moves up and the one with the lower number moves down.

https://youtu.be/o5SVOHFG7vU

Teaching drones to communicate with each other is more feasible than trying to coordinate every drone in the sky from a central flight command centre, Srinivasan says. “Especially now that drones are being built in large numbers,” he says.

Javaan Chahl of the University of South Australia agrees, but says that we are still some way off developing technology solutions that can achieve what birds do naturally.

Journal reference: PLOS ONE