My field guide quickly identified them as "Halloween Pennants"--so named because of their orange color and their habit of perching at the top of a plant, with wings and abdomen extended like a pennant in the breeze. Their Latin name is Celithemis eponina.
The two I found were perched atop last year's ragweed stalks, and they had all they could do to keep from blowing away in the wind, banner and all.
I was happy to find them in the prairie restoration! They lay their eggs in water, and for that they could use McDowell Creek, just a wingbeat or two away. The newly hatched larvae are aquatic and carnivorous. But the adults need to eat flying insects, and to get flying insects, you need a variety of plants. I am happy that even in this drought year there is water in the creek and a variety of blooming plants in the Creek Field.
Since I am finding adult dragonflies in the Creek Field, I am eager to see if I can find their aquatic larvae in the creek!