A South African mining company has lost nine unmanned aerial vehicles to eagle attacks since beginning operations near Kambalda, Australia, a local news station said.

The UAVs, which St Ives Mine surveyor Rick Steven says should not be called drones because they require trained human pilots, are used to survey and photograph mined landscapes. Their 1-meter (3.2 feet) wingspan sets off the territorial instincts in wedge-tailed eagles, which can have wingspans up to 9 feet.

The mining company tried to deter the eagles by giving the machines new livery. Painting them to look like baby eagles worked for 50 flights, but eventually the eagles caught on and went back to knocking the UAVs out of the sky.

This can be a big problem for the birds, too. Police eagles may need specialized armored boots to take down drones, but the wild birds have no such advantage against UAVs that can fly up to 92 kilometers per hour (57 miles per hour).

Finally, the mining company had to work around the eagles’ schedule instead of trying to change their natural behavior. Because eagles are most likely to fly in the middle of the day when warm thermals spiral up from the ground, Steven and his pilots fly the drones in the early morning. They haven’t had any losses since they started flying outside the eagles’ normal flight time.

The drones cost about $20,000 each, ABC said. ABC also has a video.