I'm still struggling to get a better shot of this species and their behavior. In this case, I had the flash attached, but did not use it. The mating here took place much earlier (20-25 minutes) than had been previously observed with what I think is this pair at another nest. I'm trying to get an idea of territorial behavior as well. This shot was taken five minutes before sunset where the timing allowed me to return to another nest I had observed earlier to capture another mating event of the species the same day. I don't anticipate this opportunity again, but will be diligent to make it happen.
It looks like it is time to bring out the flash. You are still not getting a high enough shutter speed at ISO 800 and it looks like your aperture is already wide open...
As much as I like natural light, I think you are going to need some flash at this time of the day, when you are trying to capture action, like here. For a stationary shot, might get by.
I certainly wouldn't hesitate to try a higher ISO, try and expose well to the right so you won't have to lighten the image and bring up the noise, but I still think you will be happier with the image quality with a bit of fill.