This red and black paper wasp (Genus Polistes) was cooling the nest by fanning its wings. As you can see in the photos, the nest is in the direct afternoon sun, where it can get very hot. I had never seen a wasp do this.
They usually put their nests in the eaves, and I saw one on the ground last summer, but I had never seen one as exposed as this one or one positioned in direct sun. It's easy for me to photo since it's slightly above eye level.
I misidentified it as a mud dauber's nest in an earlier post. Upon review, I saw that it was a paper wasp nest, although shaped differently from others I've seen
When I first saw the wasp, it was moving onto the front of the nest, providing an opportunity for a clear photo of the wasp I can see the wing of a second, but I was unable to determine what it was doing.
then it started fanning
and moving across the front of the nest