https://thenextweb.com/syndication/2019/04/02/scarecrow-drones-keep-birds-away-from-crops-without-causing-them-harm/

As drones have become more common and affordable, many animal-loving people have worried about their tendency to scare wildlife. Yet that problem may have a silver lining: drones might be used to scare animals away from crops, resolving conflicts with fright rather than lethal force.

In a study published in the journal Crop Protection, researchers led by Zihao Wang, an aerospace engineer at the University of Sydney, describe their deployment of an unmanned aerial vehicle (UAV) at Australian vineyards confronted by  ravens and cockatoos with a taste for grapes. This is no small matter: some vineyards have reported crop losses of up to 83 percent, and current methods of crop protection leave much to be desired.