There were quite a number of these that started foraging and patrolling dirt-path territories after the sun went down to the point that most of the park was in shadow.
I'm tentatively ID'ing as B. mendax, but it also strongly resembles B. praecox. I don't know though.
There were several of these flying around in this area. I had not seen them on my previous stop here.
New county record.
Only the 2nd one of these that I have seen.
Taken while scouting the Shield Ranch Conservation Corps area for two wildlife observation hikes next week. I was very lucky to have Terri Siegenthaler, director and land steward of the ranch, show me around and brainstorm with me about the hikes!