Why birds and bees do not collide?

The Japanese car manufacturer Nissan is engaged in creating robots to prevent accidents on roads due to collision – the robots are named Eporo. Having successfully developed robots BR23C that work on the principle of the bumble bee, the Japanese are now onto fish. All of us must have wondered why cars crash on the roads or trains crash due to poor visibility or why aeroplanes collide in the air or during take off and why birds and bees and fish can safely maneuver without colliding into each other. It would save millions to the insurance companies and, hospitals would have to be content with treating who complain of cough and cold. Even the Accident Relief vehicles and trains would become redundant. It would become an accident free world. That is what the Japanese are trying to evolve. They are carrying out research on the behavior of fish as a first step.