Predators are an integral part of the bird population, one of the smallest and most active being the LOGGERHEAD SHRIKE. This black-and-gray bird gorges itself on beetles and grasshoppers when insects are abundant, turning to lizards, rodents, and small birds at other times. It has the unusual habit of impaling its prey on thorns for future use. The RED-TAILED HAWK is the commonest of the large soaring hawks, which live mainly on rodents and reptiles. It builds its large stick nest in the forks of saguaro arms. Like the shrike and the SPARROW HAWK, the red-tailed hawk is found in grasslands, chaparral, and woodlands as well as in the desert. Because of their nocturnal habits, owls are not often seen by visitors, but they are abundant in the monument. In addition to the GREAT HORNED OWL, which like the red-tailed hawk feeds principally on rodents and builds cumbersome nests in saguaro branches, the SCREECH OWL and the tiny ELF OWL are numerous in the cactus community. Screech and elf owls make use of abandoned woodpecker holes in saguaros, not so much for nesting as for dark and comfortable hiding places during daylight hours; they emerge after sunset to hunt insects and small rodents. Best known of the carrion eaters, the TURKEY VULTURE is rarely seen on the ground, but is a common sight, singly or in groups, circling high in the sky. [Illustration: The red-tailed hawk builds its nest in the fork of a saguaro and by day ranges over the entire monument in search of prey.] The oak-pine-juniper woodland has its set of birds too. One of the noisiest, most quarrelsome, and most mischievous is the MEXICAN JAY, a permanent resident. In summer, it shares this habitat with the night-flying poor-will, which closely resembles the nighthawk but lacks the white wing patches. Shy, secretive, and protectively colored, this bird is rarely seen, but its plaintive call is a familiar twilight sound at the middle elevations of the mountains. Here, too, is found the strikingly patterned HARLEQUIN QUAIL, which waits until you are almost upon it before flushing. The _RUFOUS-SIDED TOWHEE_ prefers brushy slopes and canyons, where it trills its monotonous song from the branch of a skunkbush or scratches noisily and industriously among the fallen leaves beneath an oak. And anywhere from the oak-pine woodland to the top of the Rincons, you are likely to startle the large BAND-TAILED PIGEON from its perch. The pine and fir forests of the higher Rincons are rich in bird life in summer, but only a few species remain the year around. Among the latter is the STELLER’S JAY, which includes insects in its summer diet but feeds mainly on acorns and other vegetable material in winter. The MOUNTAIN CHICKADEE is busy among the branches of the large pines and firs even when snow lies deep on the ground. PIGMY NUTHATCHES—tiny, constantly twittering insect-eaters—also remain all year.