Western Australian Goldfields surveying tools are reportedly being destroyed by eagles, costing the South African company more than $100,000.

Unmanned aerial vehicles (UAV), also known as drones, are used to survey mines in St Ives and cost about $20,000 each, the ABC reports .

Rick Steven, a mine surveyor in the region, said nine of his Trimble UX5 drones had been lost to wedge-tail eagles, which he has labelled “the natural enemy of the UAV”.

After the attacks on his equipment began, Mr Steven attempted to camouflage the drones as baby eagles, but the technique only temporarily diverted the eagles.

Mr Steven said he had successfully made 50 flights with the disguised drones before the birds figured out they were not baby eagles.

"Eagles are extremely territorial birds," Mr Steven told Mashable .

"Seeing a UAV in the sky, obviously they consider it a threat and something that's encroaching on their territory."

Mr Steven said he has since figured out how to combat the territorial eagles without camouflaging his UAVs – by flying them at a time the birds are not in the sky.

"I know the eagle loves to fly on thermals. Thermals activate during the hottest part of the day — which is why we're flying first thing in the morning now," he explained.