It is a war that has been raging since the beginning of agriculture, but now farmers have a new weapon in the battle to keep birds from eating their crops - laser shooting robots.

Farmers in Holland have been trialling a new type of scarecrow that fires green laser beams across fields to keep birds away from crops.

The system, called Agrilaser, uses an automated robot that can be programmed to sweep lasers at random across areas ranging from 200 acres to more than 3,000 acres.

Researchers have been developing the robotic scarecrow in an attempt to produce bird repellents that are more socially acceptable than noise based methods that are commonly used.

Most farmers combine these loud noises, usually from propane canons or firecrackers, with traditional scarecrows that mimic the shape of humans, to keep birds away from their crops.