I took the picture of the Hyla in Sycamore Canyon, in the Santa Cruz Co., in southern Arizona. I was out looking for the wonderful Hydroscapha, a minute beetle that lives on algae, and which is a member of the small, enigmatic suborder Myxophaga. But I also had my camera, so that I could take pictures for the Tree. The frog was out sitting on a rock in a streambed, and it just sat there as I took several pictures.
It was in 1994 (2 October).