I spotted this dragonfly during a recent visit to Occoquan Regional Park. I got a glimpse of the markings on its body as it zoomed past me, so I knew that it was a spiketail, but I was not sure about the species. I watched it patrol up and down a small stream and managed to finally get a shot of the dragonfly when it perched momentarily.
It turned out to be a Brown Spiketail (Cordulegaster bilineata), one of several spiketail species that I have seen in the past at this park. During most of my previous encounters with spiketails, they have been perching on vegetation in sunlit areas along a trail.
In this case, the area where the dragonfly was patrolling was mostly in the shade, so it was a real challenge to track and photograph the dragonfly. In case you are curious, I took the photo with my Canon 7D DSLR and my Tamron 18-400mm lens extended to 400mm with settings of ISO 800, F/8.0, and 1/320 sec. The settings were not optimal for getting a shot, but they worked well enough.
© Michael Q. Powell. All rights reserved.
Mike Powell 
He appears to have flown through some spider webs. I wonder if he steels prey from the spiders the way some small birds do?
I noticed the webs too. I’ve seen dragonflies caught in spider webs before, so it is a potentially dangerous game if the dragonfly is trying to steal prey–the predator could easily become prey.