Within the Class Aves, Owls belong to the Order Strigiformes, whose most obvious features are forward-facing eyes which are set in a pronounced facial disk, large heads which appear to sit atop very short necks, and a distinctive patterning of feathers which permits very silent flight. Owls have adapted their predatory lives to almost every earthly habitat from deserts to the arctic to tropical rainforests (and are absent only from the Antarctic and some remote islands in oceania). Two main Families are distinguished: the Strigidae -- the Barn Owls -- and the Tytonidae, or "Typical Owls". We have members of both Families in Saguaro Juniper lands. At left you see the silhouette of a Great Horned Owl (Bubo virginianus), captured at twilight on the branch of a dead tree near the San Pedro River in late November of 1997. This is the most widespread owl species in North America, found well into the Arctic and with several varieties around the continent. It is large -- the size of a Red-tailed Hawk -- and bulky in shape, with the long ear tufts and a conspicuous white throat bib. It hunts animals up to rabbit-sized, and makes an eery nocturnal call that sounds like a high-pitched "Who's awake?..Me, Too". (Thanks to Richard Walton & Robert Lawson, 1990, Western Birding by Ear, Peterson Field Guides Series, Disk 1 Track 3. This is a wonderful birdsong guide.)
Owls have very large eyes for their body size (even larger than they appear), and they can see well both at night and in daytime (many species are daytime hunters).The Great Horned caught at left in twilight with a flash camera illustrate this point. They have a "third eyelid" which shields the very sensitive retina from the brightest light. The eyes have a narrow field of vision, compensated for by the very pliant necks these birds possess, enabling them to twist their heads a full 180 degrees. Their hearing is highly acute, and their distinctive facial disks are thought to function like parabolic reflectors to gather sound. The nocturnal owls have sound-deadening filaments at the tips of their flight feathers which enable them to surprise their prey, which they generally swallow whole and eventually regurgitate as pellets.
The Barn Owl (Tyto alba) may be one of the most common owls of our Saguaro Juniper area, but they are seldom seen. We have encountered them mainly in the various cliffside clefts on our lands, where they rest during the daytime on ledges inside these hidden rocky retreats -- see this image at the right, showing a nest we found in July of 1995 while exploring one of these deep, cool, labyrinthine clefts, having startled (and been greatly startled by) a large barn owl who flew high above us while heading off out of sight, too fast for the cameraperson to respond. This was its nest. These nests are high overhead, inaccessible to predators, and we have encountered Barn Owls in such startling fashion in several of them. (So far, no successful photographs.)
We have also seen them in the daytime, very occasionally. One was sitting on a ledge in Cottonwood Seeps Canyon, flying off with a loud hiss (its characteristic call), and another was observed a short ways below the Big Tank, being shadowed by a Raven. This Barn Owl flew only a short distance each time, to move up-wash from the approaching vehicle, and this fact together with the stalking Raven suggested to us it was in some way injured or sick. (It surely had no friend in the silent, persistent follower.)
Barn Owls are large birds (16" long, with wingspan of about 42"), distinguished by their white heart-shaped face and very dark eyes. Their coloration is rather spectacular, with pale tawny-to-cinnamon upper wings and back and ghostly-pale underparts.
We also see the Western Screech Owl (Otis kennicottii) -- a common sight in the trees near the Hot Springs Canyon Windmill. This is a small owl with conspicuous ear tufts and usually is gray in color. It makes a series of hollow whistle sounds on one pitch, sounding like the "rhythm of a small ball bounding to a standstill" [Peterson p.200].
The Elf Owl (Micrathene whitneyi) is tiny (5-6" long), with a very short tail and earless, is mainly nocturnal but sometimes seen by day (we encountered one at noon one August day at Sierra Blanca Spring). It lacks ear tufts. It is also common in our woodlands in the summertime, but migrates into Mexico for the winter.