Yva Momatiuk & John Eastcott / Barn Owl (Tyto alba) portrait against blue sky in desert, spring, Arizona-Sonora Desert Museum, Arizona

Dr. Axel Gebauer / Costa's Hummingbird (Calypte costae) perched on branch showing iridescence. Arizona-Sonora Desert Museum, Tuscon, Arizona, USA, Small repro only

Dr. Axel Gebauer / Costa's Hummingbird (Calypte costae) with light at angle where iridescence does not show. Arizona-Sonora Desert Museum, Tuscon, Arizona, USA, February.

Yva Momatiuk & John Eastcott / Mountain Lion (Puma concolor) peering from cave, Arizona-Sonora Desert Museum, Arizona

Kevin Schafer / Torch Cactus (Trichocereus sp) flowers, Arizona-Sonora Desert Museum, Tucson, Arizona

Norbert Wu / Hammond's Spadefoot Toad (Spea hammondii), Arizona-Sonora Desert Museum, Tucson, Arizona

Norbert Wu / Bighorn Sheep (Ovis canadensis) ewe, Arizona-Sonora Desert Museum, Tucson, Arizona

Norbert Wu / Sonora Chub (Gila ditaenia) swimming, Arizona-Sonora Desert Museum, Tucson, Arizona

Norbert Wu / Desert Pupfish (Cyprinodon macularius) pair, Arizona-Sonora Desert Museum, Tucson, Arizona

Norbert Wu / Desert Pupfish (Cyprinodon macularius) pair, Arizona-Sonora Desert Museum, Tucson, Arizona

Rob Tilley / Saguaro cactus flower (Carnegiea gigantea) detail with fly, against blue sky. Sonora Desert Museum, Tucson, Arizona. April 2006

Rob Tilley / Ocotillo / Coachwhip / Jacob's Staff in flower (Fouquieria splendens) against the sky, Sonora Desert Museum, Tucson, Arizona, USA