Limenitis arthemis arizonensis
Arizona Red-spotted Purple
This beauty is not uncommon patrolling along creeks in southern Arizona, often with Arizona Sisters present as well. They stray into California into the eastern Mojave Preserve; Ken Davenport mentions Fort Piute "in streambed with willows". Since it is known to breed just over the border at the Bill Williams National Wildlife Refuge on the Colorado River, it wouldn't be surprising if it is also at least occasionally breeding on the California side. The type locality is Tucson. Hosts include willows, cottonwood trees, quaking aspens, and chokecherry, according to Stewart et al., Butterflies of Arizona: A Photographic Guide, p.194. So streamsides are the right habitat, from March to November.