Crowded Skies.

There was a time when a drone was known as a bumble bee or perhaps an idle person. Today the definition is a "quadcopter" or a recreational drone, the type that lands on the White House lawn or disrupts airline operations. But they are also becoming the enemy of wildlife. Last year a red tailed hawk attacked a drone, flipping it in midair.
The FAA estimated that one million drones will be sold in the U.S. this Christmas and
  the government is rushing to try to register these unmanned aerial vehicles. The friendly skies are becoming very crowded.
tjs
http://www.nytimes.com/2015/10/20/science/animals-spy-a-new-enemy-drones.html?rref=collection%2Fsectioncollection%2Fscience&action=click&contentCollection=science&region=rank&module=package&version=highlights&contentPlacement=6&pgtype=sectionfront