Poachers backed by international crime syndicates are slaughtering elephants and rhinos just for their highly valuable tusks and horns.

As GPS-tagged armed rangers and sniffer dogs patrol game reserves across Africa, unmanned aerial vehicles, or drones, could provide them with a powerful new tool in the battle to preserve the continent's endangered species.

The Ol Pejeta Conservancy in Kenya has been experimenting with the new technology. Its chief commercial officer, Robert Breare, discusses the pros and cons of this "eye in the sky".