How do bees and birds navigate?

Ever wondered how bees and birds make such a smooth landing on flowers in your garden?

Prof Mandyam Srinivasan, professor of Visual Neuroscience at the Queensland Brain Institute, University of Queensland has been trying to unravel the mysteries around this. “Landing is a tricky aeronautical manoeuvre. That's why aircraft pilots are paid so much,” he says. “Birds and bees seem to have a beautiful autopilot. They don't have radar or GPS. However, they have excellent vision systems and they are able to reduce their speed, as they come closer and closer to the ground and land smoothly,'' says Srinivasan, an India-born scientist who is a fellow of the Australian Academy of Science and the Royal College of London.

Srinivasan, an alumnus of the Indian Institute of Science, Bengaluru came back to his alma mater to interact with present students and the media.
A bee brain is just the size of a sesame seed, says Srinivasan. It works in a similar way as the so-called higher brains. “We are trying to see how creatures like bees, with small brains and limited computing capacity manage to see and navigate remarkably well. We watch them without any hypothesis and see if we can make some sense out of it. It could perhaps helps us come up with similar biologically inspired ideas to guide drones and aircrafts that navigate autonomously, without the use of radar and things like that,'' he says.

In one of their experiments, Srinivasan and his team of researchers trained bees to fly down a tunnel. Using a high speed camera, they recorded their movements. ''What we found is that they fly down the middle of the tunnel. But when we moved one of these walls of the tunnel in the same direction as the incoming bee, the bees flew closer to the wall. What we found is that if the bees and the wall are moving in the same direction, the image speed as seen by their eye is slower. So they tend to think the wall is further away. If you move the wall in the opposite direction, the bee thinks there is something dangerously close on that side and so they fly away from the wall,'' he explains.

Birds and bees are aware of their body dimensions, which helps them while having to fly through narrow spaces, says Srinivasan. ''Each bird has its own personal body image and it is extremely good at gauging the width of apertures,'' he says. If the aperture is wider than its wing span, a bird or bee will fly through it. “But if the width of the aperture gets close to their wing span, they spend a lot of time, hovering in front of the aperture, hesitating to go through it,” observes Srinivasan.

Srinivasan and his team of researchers have conducted 800 flights using eight different breeds of birds. They have also looked at how bees passing each other try to avoid head on collisions. What they found was that each bee tries to turn to its left, as if following a traffic rule.