As the sun set over the Sonoran Desert, the animals came out to play. The deer grazing among the saguaro were probably mule but could have been white-tailed — it was tough to say at dusk with only mini red-light flashlights in hand instead of binoculars. The bird that perched on a tree branch for a few seconds before flying away had the distinctive silhouette of an owl. There was no mistaking the yips and howls of coyotes.