This is the second summer in a row that I've seen dragonflies on a feeding frenzy in the Dundalk neighborhood of St. Helena.
Those are the only times I've seen a lot of them swarming together. They're usually seen by themselves or with just a few of them visible in the same area.
I've uploaded some videos of them. The dragonflies were swooping on and eating up small white bugs in the air.
These videos are good for anyone wanting to study, or just enjoy, the amazing aerial abilities of dragonflies.