Elf Owl (Micrathene whitneyi) 5.25 inches long
This tiny owl, hardly bigger than a sparrow, is the smallest owl in the world. It inhabits saguaro deserts and wooded canyons. It feeds by night, mainly on insects and other arthropods including scorpions and spiders. It has a large, rounded head, yellow eyes and brown upperparts with white spots, brown and gray breast with white belly. Somewhat rare in the U.S. (probably because of loss of habitat), it inhabits the Mexican border area of Arizona. Since it feeds mainly on insects, which are unavailable in winter, it is strictly a summer resident north of the Mexican border, arriving early in spring and departing fairly early in fall. Also shown in the drawing is the Sonoran whipsnake; the drawing is from The Sonoran Desert by Day and Night by Dot Barlowe, referenced below.
Alderfer, Jonathan (ed.). National Geographic Field Guide to Birds: Arizona/New Mexico . Washington, D.C.: National Geographic, 2006. This handy, really pocket-size (4x6) guide includes most of the birds you're likely to see in Arizona. In addition to a photo, it includes information about behavior, habitat and specific local sites where you are likely to find the bird.
Barlowe, Dot. The Sonoran Desert by Day and Night: A Dover Coloring Book. New York: Dover Publications Pictorial Archive Series, 2002.
Cameron, Angus. The Nightwatchers. New York: Four Winds Press, 1971. Unfortunately this book seems to be out of print. It contains charming write-ups of the author's personal experiences with owls and wonderful drawings by Peter Parnall of the birds in their natural settings. It is worth looking for if you can find it in your library or used book store.
Corman, Troy E. and Cathryn Wise-Gervais (eds.) Arizona Breeding Bird Atlas. Albuquerque: University of New Mexico Press, 2005.
Johnsgard, Paul A. North American Owls: Biology and Natural History (Second Edition). Washington, D.C.: Smithsonian Institution Press, 2002.