The name Dryobates scalaris bairdi, which was for a long time used to designate the ladder-backed woodpeckers of the United States, was restricted by Oberholser to a Mexican form. He gave as the characters of cactophilus, “much like Dryobates scalaris eremicus, but smaller, particularly the tail and bill; lower surface lighter, laterally almost always streaked with black; upper parts lighter—the black bars on back and scapulars narrower; wing-quills with larger spots and broader bars of white; outer long rectrices with exterior webs barred throughout with black; black bars on posterior lower surface narrower.”
Ridgway (1914) compares it with symplectus, the Texas bird, as “slightly larger, and with black bars on back, etc., decidedly broader.”
The cactus woodpecker ranges, according to the 1931 A. O. U. Check-List, from “central western Texas through New Mexico and Arizona to extreme northeastern Lower California and southeastern California, north to extreme southern Nevada and southwestern Utah, and south to northern Durango.” It frequents the deserts, or the borders of the deserts, and the lower slopes of the mountains in the Sonoran Zone, a hot, dry region where there are no trees of any size and where this is about the only species of woodpecker found. We never found it in the giant-cactus, or saguaro, region, where it seemed to be replaced by the noisy Gila woodpecker and Mearns’s gilded flicker. W. Leon Dawson (1923) says:
Of course it must not be understood that the Cactus Woodpecker tries to live in the central wastes of the desert; for however much it may forage over the creosote and cholla patches, on occasion, it requires something of more ample girth for a nesting site. Hence its breeding range is confined to the more fruitful upper edges of the Lower Sonoran zone, and to the moister bottoms. In the former situation the dried stalks of the agave and the lesser yucca (whipplei), or of the Joshua tree (Yucca arborescens), and the Mohave Yucca offer asylum. In the valley of the Colorado, fearing no rivalry from D. pubescens turati, the Cactus Woodpecker is able to monopolize the willows which grow so rankly along the lagoons.
Referring to Arizona, Harry S. Swarth (1904) says: “This woodpecker is seldom seen above 5,500 feet, and rarely ventures into the canyons. On the plains below, wherever there is brush or trees, and all along the San Pedro River it is very common, as in fact, I have found it in all similar places I have visited in southern Arizona.”
Swarth says elsewhere (1929):
In southeastern Arizona, east of the Santa Rita Mountains, the vast areas of prairie land are for the most part unsuitable to this species. Wherever even a scanty growth of chaparral has found a foothold, though, the Cactus Woodpecker is pretty sure to occur, for it does not require large trees. Along the streams and washes in this same area, as elsewhere, it does frequent the sycamores and other larger growths, but these do not form the preferred habitat. In the lowlands west of the Santa Rita Mountains this woodpecker is in the surroundings that suit it best. It does not frequent the giant cactus (I do not believe that there is a known instance of its nesting in one), but stays nearer the ground, in cholla cactus, creosote bush, catclaw or other low-growing vegetation.
Nesting.—Major Bendire (1895) writes:
In southern New Mexico and Arizona it nests sometimes in the flowering stems of the agave plant and also in yucca trees, and I have found it nesting on Rillito Creek, Arizona, in a small dead willow sapling not over 3½ inches in diameter. The cavity was about 12 feet from the ground and 10 inches in depth, and the entrance hole a trifle over 1½ inches in diameter. This nest was found on June 8, 1872, and contained only two eggs, in which incubation was about one-half advanced; the eggs laid on fine chips. The nesting sites are placed at various distances from the ground, from 3 to 30, usually from 6 to 14 feet. Dead branches of trees or partly decayed ones seem to be preferred to live ones. * * * It nests by preference in mesquite trees, one of our hardest woods, and it must require a long time to chisel out a nesting site in one of these trees. While it is true that the heart is usually more or less decayed, the birds have first to work through an inch or two of solid wood which is almost impervious to a sharp ax.
Mrs. Florence M. Bailey (1928) says that in New Mexico the nests are “from 2 to 30 feet from the ground in holes in mesquite, screw bean, palo verde, hackberry, and China trees, willows, cottonwoods, walnuts, oaks, and other trees, telegraph poles, fence posts, and stalks of agave, yucca, and cactus.”