Great Basin Naturalist Volume 41 Number 2 Article 16 6-30-1981 Avifauna of the Mt. Dellenbaugh region, Shivwits Plateau, Arizona John G. Blake University of Illinois, Champaign, Illinois Follow this and additional works at: https://scholarsarchive.byu.edu/gbn Recommended Citation Blake, John G. (1981) "Avifauna of the Mt. Dellenbaugh region, Shivwits Plateau, Arizona," Great Basin Naturalist: Vol. 41 : No. 2 , Article 16. Available at: https://scholarsarchive.byu.edu/gbn/vol41/iss2/16 This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. AVIFAUNA OF THE MT. DELLENBAUGH REGION, SHIVWITS PLATEAU, ARIZONA' John G. Blake- Abstract.— An investigation of the avifauna of Mt. Dellenbaugh, Arizona, and nearby areas on the Shivwits Plateau was conducted during fall 1974 and during spring and summer 1975. A total of 92 species of birds was re- corded, of which 56 were considered resident. Species composition is discussed in relation to habitat. From an ornithological standpoint, the National Recreation Area. The northern Shivwits Plateau in northwestern Arizona has boundary of the recreation area crosses the been neglected. In fact, bird studies in the southern edge of the Shivwits Plateau, close entire region (northwestern Arizona, south- to Mt. Dellenbaugh. As a consequence, sever- western Utah, and adjoining parts of south- al trips were made to the Shivwits Plateau by eastern Nevada) have been limited. The need members of the NPS study team, with obser- for work in this part of Arizona is evident vations taken on occurrence and distribution from an examination of distribution maps in of flora and fauna. The present paper pres- Birds of Arizona (Phillips et al. 1964) and is ents an account of bird species observed. Dis- further emphasized by Monson and Phillips tribution of birds within different habitats is (1964:178). Despite this lack of information, discussed. virtually no work has been conducted on the Place names and topographical informa- Shivwits Plateau and nearby areas. tion used in the present report are taken Mt. Trumbull, located approximately 50 from U.S.G.S. 1:250,000 topographical maps. km NE of Mt. Dellenbaugh on the Uinkaret Plateau, was visited for by Huey (1939) ap- Study Area proximately two weeks in late July; Mt. Trumbull is the closest reported study area to The Shivwits Plateau is primarily flat ta- that part of the Shivwits Plateau covered by bleland, with occasional lava-capped buttes the present report. Farther east, Rasmussen and isolated mountains. Over much of the (1941) and Jenks (1931) have reported on bird southern part of the plateau elevation is ap- communities of the Kaibab Plateau. In- proximately 1830 m. Northward, the plateau vestigations on avifauna of south central and stretches toward Utah, gradually decreasing southwestern Utah have been somewhat in elevation. The southern boundary is more extensive (Presnall 1935, Hardy and marked by an abrupt descent to the Sanup Wiggins 1940, Behle 1943, Behle et al. 1958, Plateau, at 1370 m. Numerous steep-walled Wauer and Carter 1965) but have not includ- canyons dissect the plateau, leading eventu- ed the Shivwits Plateau region. Farther west, ally to the Colorado River. Mt. Dellenbaugh, several authors have examined the desert avi- the highest peak in the southern part of the fauna of the Virgin River Valley in Nevada, plateau, reaches an elevation of 2130 m. Ap- Arizona, and Utah (Tanner 1927, Wauer and proximately 8 km NE is Yellow John Moun- Russell 1967, Wauer 1969, Behle 1976, Whit- tain, which reaches an elevation of 2060 m more 1977). (Fig. 1). In 1975, a study was initiated by the U.S. Observations are primarily from the vicin- National Park Service Cooperative Resources ity of Mt. Dellenbaugh and Green Springs Studies Unit located at the University of Ne- Canyon; additional observations were made vada, Las Vegas, to document distribution of on a trip along Twin Point (Fig. 1). Various plants and animals within the Lake Mead distinct habitats occur at different locations 'This work was supported by NPS/UNLV Contracts 8000-4-0031 /CX 8000-6-0034. 'Department of Ecology, Ethology, and Evolution, Vivarium Building, University of Illinois, Champaign, Illinois 61820. 259 260 Great Basin Naturalist Vol. 41, No. 2 UTAH NM T13'45 36''15 36°00 Fig. 1. The southern part of the Shivwits Plateau is shown, with sites mentioned in the report indicated. Location of the plateau within Arizona is shown in the upper right. June 1981 Blake: Arizona Birds 261 and are briefly described below. Plant identi- others are bordered by relatively dense stands flcation was by members of the NPS study of shrubs, particularly rabbit brush. team. All habitat types described above occur at Predominant vegetation over most of the or near Mt. Dellenbaugh. A large sagebrush Shivwits Plateau is pinyon pine {Pinus mono- field occurs just north of the mountain and phyla) - juniper {Juniperus osteosperma) has been maintained in part for use as a land- woodland. Understory is sparse within this ing strip. Cattle also graze over parts of the open, relatively xeric woodland, consisting field; several ponds occur in or around the primarily of sagebrush {Artemisia) and scrub perimeter of the field. Pinyon-juniper wood- of the mountain ex- oak {Quercus). Locally concentrated patches land surrounds much and tends south to the plateau edge. Pinyon- of oaks and sagebrush produce a more brushy juniper extends part way up the slopes of the appearance in certain areas (e.g., southern mountain, particularly on the northern face. end of Twin Point). Ponderosa pine occurs in belts near the base Ponderosa pine {Pinus ponderosa) occurs in of the mountain, bordering the sagebrush at limited amounts, principally along drainages numerous points. Mixed oak scrub pre- where soils are deeper and moisture condi- dominates over much of the mountain slope. tions higher. Scattered individuals occur Green Springs Canyon is located approx- throughout the area. Due to drainage pat- imately 6 km ESE of Mt. Dellenbaugh (Fig. terns, ponderosas occur primarily as belts in- 1). Pinyon-juniper woodland predominates terspersed in pinyon-juniper woodland and over much of the surrounding plateau. An bordering open sagebrush fields. Understory open ponderosa pine stand occurs at the head and ground cover are sparse, with a mixed of the canyon. The stand was logged at some shrub assemblage that includes species of oak, time in the past, and presently is composed sagebrush, mountain mahogany {Cercocarpiis of large, widely spaced trees, forming a more montanus), and others. parklike appearance than is found elsewhere. Upper slopes of Mt. Dellenbaugh and Patches of sagebrush occur at scattered loca- edges and slopes of various canyons are cov- tions, but large expanses are absent from the ered with a mixed assemblage of relatively area. Canyon slopes and edges are covered bmshy shrubs and trees, which produces a by oak scrub, with Gambel oak particularly chaparral type habitat. Although oaks, in- prevalent in patches on midslopes. The can- cluding scrub oak {Quercus turbinella), Gam- yon bottom is quite moist and supports a lim- vegetation. bel oak {Q. gambelii), and wavyleaf oak {Q. ited amount of riparian undulata), are particularly abundant, numer- Twin Point is predominantly pinyon- the ous other shrubs also occur, including moun- juniper woodland with oak scrub along of the tain mahogany and manzanita {Arctosta- plateau rim and at the southern end sagebrush fields occur at several phylos piingens). Particularly on the slopes of point. Large plateau. Mt. Dellenbaugh, New Mexican locust {Rob- locations along the inia neomexicana) occurs in locally dense stands. Methods Large expanses of sagebrush {Artemisia tri- dentata) occur at a number of locations on Mt. Dellenbaugh was visited in fall 1974 the plateau. In a number of instances, juniper (28 September, 4-5, 12-14 October), and trees have been cleared, and large piles of spring (17-18 May) and summer (7,9,27-29 dead trees add a significant component to the June) 1975. Green Springs Canyon was vis- habitat. Additional plant species occurring ited 28-29 September 1974 and 16 May and with sagebrush include rabbit brvish {Chryso- 6,8 June 1975. A trip was made to the south- thamnus spp.), snake weed {Gutierrezia mi- ern end of Twin Point 6-7 October 1974; the crocephala), and others. northern end was briefly visited again on 7 Several ranchers graze cattle on the June 1975. Thus, a total of 19 days was spent plateau, and a number of ponds have been in field observations. dur- constructed to supply water. Vegetation is No regular censuses were conducted virtually absent around some ponds, but ing the study, but all habitats were surveyed 262 Great Basin Naturalist Vol. 41, No. 2 on a regular basis. Observations were con- trips, but seen in large numbers on each trips, ducted on foot and were concentrated in the were designated as common. This method is morning, from approximately one-half hour subjective, but with criteria consistently ap- prior to sunrise until approximately 4-5 plied does provide an index of abundance. hours after sunrise. Additional observations were made throughout the day with a second Results concentrated effort in the evening. During observation periods, a count was kept of the A total of 92 species was recorded during number of individuals of each species seen. visits to the Shivwits Plateau (Appendix). Of The trip out from Twin Point involved peri- these, 13 were observed only in 1976, includ- odic stops for observation as well as observa- ing one summer resident (Poor-will), 3 mi- tions from the vehicle.