A new study in the journal Current Biology says that people who buzz wildlife with drones might very well cause stress to the animals, even though the critters being buzzed might not show overt signs of being agitated.
Scientists who conducted the study monitored the heart rates of black bears as a drone flew near the bears. Though the animals appeared impassive, their heart rates spiked whenever the drones approached.
On a related note, not all animals are content to sit (or fly) idly by when a drone approaches. In Australia, a wedge-tailed eagle became a You Tube sensation when it attacked a flying drone and knocked the contraption plumb out of the sky.
Apparently drones irk wildlife as much as they do some people.