I know generally where I was when I took this picture. It was the headquarters of the Cabeza Prieta National Wildlife Refuge in Ajo, Arizona. And this bird is definitely a cactus wren. But for some odd reason this bird seems undersized to me, more Bewick wren sized. The bird is sitting on a buckhorn cactus and the stems of the cactus are not very large. I had to go look at pictures of all the other possible wrens to convince myself that this bird is indeed a cactus wren. A bit scruffy. Maybe molting, making the bird look a bit smaller? Maybe they are smaller over here?
They just started singing.