While editing a video I took 2 months back there is a supersonic bird / insect flying by. Watch the right side crossing over to the middle bottom at incredible speed. I took the video with a gopro 3 white edition at 1920 pixels / 30 fps. The video show first the normal speed, than 50%, than 25% and finally 10%. During the 10 minutes filming there were a lots of doves flying around but no small birds. This things seems to appear from nowhere!