(DRAFT) - Taxonomy
                             Species PRONGHORN, SONORAN
                                Species Id ESIS052001
                                   Date 14 MAR 96



TAXONOMY

NAME - PRONGHORN, SONORAN OTHER COMMON NAMES - PRONGHORN, SONORAN; ANTELOPE; ANTELOPE and AMERICAN; PRONGHORN ELEMENT CODE - CATEGORY - Mammals PHYLUM AND SUBPHYLUM - CHORDATA, CLASS AND SUBCLASS - MAMMALIA, ORDER AND SUBORDER - ARTIODACTYLA, FAMILY AND SUBFAMILY - ANTILOCAPRIDAE, GENUS AND SUBGENUS - ANTILOCAPRA, SPECIES AND SSP - AMERICANA, SONORIENSIS SCIENTIFIC NAME - ANTILOCAPRA AMERICANA SONORIENSIS AUTHORITY - TAXONOMY REFERENCES - COMMENTS ON TAXONOMY - Sonoran Pronghorn Antilocapra americana sonoriensis Goldman, 1945 KINGDOM: Animal GROUP: Mammal PHYLUM: Chordata CLASS: Mammalia ORDER: Artiodactyla FAMILY: Antilocapridae The taxonomy of the Sonoran pronghorn (Antilocapra americana sonoriensis) is poorly understood as little taxonomic material is available and the original description is based on only two specimens. The subspecies was first described by Goldman (01) from a type specimen taken near Costa Rica, Sonora, Mexico by Vernon Bailey and Frederic Winthrop on December 11, 1932. It was described as being the smallest subspecies of Antilocapra americana. Other differential characteristics noted were a general paler coloration and distinctive cranial features. The major subspecific differences noted in the cranial features of A. a. sonoriensis were: 1) skull decidedly smaller, 2) frontal depression shallower, 3) premaxillae less extended posteriorly along median line, and 4) auditory bullae more flattened, less projecting below level of basioccipital. Paradiso and Nowak (02) examined the skulls of three juvenile and one adult male Sonoran pronghorns that had been collected near Caborca Taxonomy - 1 (DRAFT) - Taxonomy Species PRONGHORN, SONORAN Species Id ESIS052001 Date 14 MAR 96 in northwestern Sonora, Mexico, in February 1969. They found the four specimens to have marked similarities to the holotype of A. a. sonoriensis and to differ from the specimens of subspecies americana, mexicana, and peninsularis in the same characteristics as the holotype. They concluded that although there are still insufficient specimens to allow a complete appraisal, the four newly acquired skulls provide strong support for the continued recognition of A. a. sonoriensis as a distinct subspecies. They also concluded that the taxon is more distinct from the other subspecies of pronghorn than any of them are from each other. The species Antilocapra americana Ord is known by the common names American antelope or pronghorn. Taxonomy - 2
                                  (DRAFT) - Status
                             Species PRONGHORN, SONORAN
                                Species Id ESIS052001
                                   Date 14 MAR 96



STATUS

Coded Status E: Federal Endangered Commercial/consumption Game (Consumptive Recreational) Non-consumptive recreational COMMENTS ON STATUS - U.S. STATUSES AND LAWS: The Sonoran pronghorn (Antilocapra americana) has been designated as Endangered pursuant to the Endangered Species Act of 1973 (50 CFR 17.11; P.L. 93-205, 87 Stat. 884; 16 U.S.C. 1531-1540), as amended. The subspecies has this status wherever found including the State of Arizona. This species is protected by the Lacey Act (P.L. 97-79, as amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import, export, transport, sell, receive, acquire, or purchase any wild animal (alive or dead including parts, products, eggs, or offspring): (1) in interstate or foreign commerce if taken, possessed, transported or sold in violation of any State law or regulation, or foreign law; or (2) if taken or possessed in violation of any U.S. law, treaty, or regulation or in violation of Indian tribal law. It is also unlawful to possess any wild animal (alive or dead including parts, products, eggs, and offspring) within the U.S. territorial or special maritime jurisdiction (as defined in 18 U.S.C. 7) that is taken, possessed, transported, or sold in violation of any State law or regulation, foreign law, or Indian tribal law. RESPONSIBLE FEDERAL AGENCIES: USFWS -Responsible for the management/recovery, listing, and law enforcement/protection of this species. BLM -Responsible for the law enforcement/protection of this species with applicable State and Federal laws on public land under their control (43 CFR 4140). Also responsible for management/recovery on Bureau of Land Management lands. DOD -Responsible for the law enforcement/protection of this species with applicable State and Federal laws on public land under their control. Also responsible for management/recovery on Department of Defense lands. Status - 1 (DRAFT) - Status Species PRONGHORN, SONORAN Species Id ESIS052001 Date 14 MAR 96 NPS -Responsible for the law enforcement/protection of this species with applicable State and Federal laws on public lands under their control. Also responsible for conservation (Nat. Park System Organic Act - 16 U.S.C. 1, 2-3)/management/recovery on National Park Service lands. Taking, possessing, or disturbing of federally listed species is prohibited on NPS lands (36 CFR 2.1, 2.2, and 2.3). All Federal agencies have responsibility to ensure that any action authorized, funded, or carried out by that agency is not likely to jeopardize the continued existence of the species or result in the destruction or adverse modification of Critical Habitat (50 CFR 402), and to utilize their authorities to carry out programs for the conservation of the species. STATE STATUSES AND LAWS: STATE: Arizona DESIGNATED STATUS: Group II, a species or subspecies whose continued presence is now in jeopardy, extirpation is probable without recovery efforts. ADMINISTRATIVE AGENCY: Arizona Game and Fish Department STATE STATUTE: Arizona Revised Statute Sec. 17-23(B)7 INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS: The Sonoran pronghorn is listed as endangered by the Mexican Departamento De Fauna Silvestre. It is protected by a cooperative agreement between the USFWS and the Mexican Departamento De Fauna Silvestre. It is listed in the 1986 IUCN Red List of Threatened Animals as Endangered, and it is also listed by CITES (Appendix 1). The Sonoran pronghorn is listed by the U.S. in the Convention on Nature Protection and Wildlife Preservation in the Western Hemisphere Annex (1970). ECONOMIC STATUSES: The Sonoran pronghorn were formerly hunted and provided a source of food for early settlers. They now provide visitors to government land in southwestern Arizona occasional opportunities for viewing. 67/03/11:32 FR 04001 - Listed as Endangered, Preact 1 70/08/25:35 FR 13519/13520 - Relisted as Endangered, Preact 6 70/10/13:35 FR 16047/16048 - Relisted as Endangered, Preact 7 79/05/21:44 FR 29565/29577 - 5-year review 85/07/22:50 FR 29901/29909 - 5-year review 87/07/07:52 FR 25522/25525 - Notice of 5-year review completion Status - 2
     

HABITAT ASSOCIATIONS

HABITAT - TERRESTRIAL TERRESTRIAL LAND USE - Shrub and Brush Rangeland Mixed Rangeland Mixed Barren Land COMMENTS ON HABITAT ASSOCIATIONS - The present range of the Sonoran pronghorn falls within the lower Sonoran desert life zone (04). There are several major subdivisions within this life zone of which the two northernmost occur in southern Arizona. These are the Arizona upland desert which is basically a paloverde-saguaro association and the lower Colorado desert which is primarily a creosote bush-bursage association (03). The paloverde-saguaro association is comprised of small-leaved trees, Sclerophyllus shrubs and numerous cacti. The best development of this association is found on rocky hills, bajadas, and other coarse-soiled slopes typical of the major mountain ranges of southwestern Arizona. Primary desert trees are foothill paloverde (Cercidium microphyllum), ironwood (Olneya tesota), mesquite (Prosopis juliflora), catclaw (Acacia gregii), crucifixion thorn (Holocantha emoryii), and smoketree (Dalea spinosa). The major cacti are saguaro (Carnegia gigantea) and barrel (Ferocactus wislizeni). One of two shrubs, triangle-leaf bursage (Ambrosia deltoidea) or brittle bush (Encelia farinosa) is almost always present in the understory as are many annual and perennial forbs and grasses (03). The creosote bush-bursage association is composed mainly of shrubs. The plant dominants are creosote bush (Larrea tridentata) and bursage (Ambrosia dumosa). Trees are usually lacking except for those found in the rocky riparian drainageways. This shrub community characterizes less rocky areas of lower relief such as the extensive valleys between the mountain ranges (03). Sonoran pronghorn habitat falls under the southwestern or Arizona climatic pattern (05), which is characterized by winter rains, spring drought, summer rains, and fall drought. Almost one half of the normal yearly precipitation (3-15 inches) falls from July-September. This precipitation, usually in the form of intense localized thunderstorms, is associated with deep currents of moisture moving across southern Arizona from the Gulf of Mexico. A precipitation maximum occurs during the winter when storms from the Pacific Ocean sweep across southern Arizona via southern California. These storms usually produce the heaviest, most widespread and effective precipitation. Heat and aridity are dominant climatic characteristics of Sonoran pronghorn habitat. During the hottest part of the year (July-August) daily maximums exceed 110 degrees F and temperatures of 120 degrees are not uncommon. The cooler winter months find daytime temperatures reaching the middle 60s and 70s and nighttime temperatures remaining above freezing (03). Habitat Associations - 1
                                (DRAFT) - Food Habits
                             Species PRONGHORN, SONORAN
                                Species Id ESIS052001
                                   Date 14 MAR 96



FOOD HABITS

TROPHIC LEVEL - HERBIVORE LIFESTAGE FOOD FOOD PART General Forb Leaves/Stems General Evergreen Shrubs-Leaves/Twigs General Cactus-Flowers/Fruit/Seed General Poaceae General General Forb Flowers/Fruit/Seed General Evergreen Shrubs-Flowers/Fruit/Seed General Parasitic/Epiphytic Plants General Cactaceae General Deciduous Trees-Leaves/Twigs General Deciduous Trees-Flowers/Fruit/Seed Food Habits - 1
                         (DRAFT) - Environment Associations
                             Species PRONGHORN, SONORAN
                                Species Id ESIS052001
                                   Date 14 MAR 96



ENVIRONMENTAL ASSOCIATIONS

Environment Associations - 1
                               (DRAFT) - Life History
                             Species PRONGHORN, SONORAN
                                Species Id ESIS052001
                                   Date 14 MAR 96



LIFE HISTORY

FOOD HABITS: Detailed life history studies have not been done on the Sonoran pronghorn, so little is known (03, 06). Throughout the years various individuals have made observations on their diet in southern Arizona and Mexico. Monson (07) concluded that pronghorn on Cabeza Prieta Game Range subsisted mainly on the remains of annual and biennial plants, especially forbs. He also noted that they will browse paloverde, honey mesquite, and ironwood. Monson (07) and Lumholtz (08) both wrote that pronghorn relish the pendant fruits of the chain cholla (Opuntia fulgida). Hornaday (09) noted pronghorn of the pinacate region eating an annual plantain (Plantago spp.). Carr (10) observed pronghorn eating cholla cactus, brittle bush, paloverde, and plantain during the spring. Arizona Game and Fish Department (11) studied the diet of Sonoran pronghorns by analyzing fecal pellets collected on Cabeza Prieta NWR. From October 1977 through September 1978, efforts were made to locate fresh pronghorn feces. Most samples were located as a result of seeing one or more pronghorn and tracking them for a distance, often a mile or more. Fresh fecal material could usually be found by this method. Because of the extensive area involved and the low density of antelope, few samples were collected. Several incidental samples from 1974 through 1977 were also available, as were several samples collected in northern Mexico by the Departamento De La Fauna Silvestre. Samples were not available from every month of the year (July, August, November, and December missing). Feces were analyzed microscopically and compared with reference slides from plants collected on the refuge. Twenty random microscope fields were read on each of 20 slides for each fecal sample collected. Frequency of occurrence of each identifiable species was converted to percent relative density. The diet of the Sonoran pronghorn, using all the fecal samples available from 1974-78, consisted of 69 percent forbs, 22 percent shrubs, 7 percent cacti, and O.4 percent grasses. Other pronghorn in the southwestern U.S. were found to have very similar diets. Beuchner (12) in Texas found that the pronghorn utilized 66.6 percent forbs, 29.7 percent browse (including both shrubs and cacti), and 3.7 percent grasses. Forbs appeared to be more important in the spring and in September and October. Late winter and spring rains in the area initiate the germination of numerous annual forbs, and Sonoran pronghorn use them extensively. Shrubs are most important in the winter as evidenced by a high density of shrub species in the January diet. Few grass species are abundant on the Cabeza Prieta, and the pronghorn there do not appear to select for grasses. This correlates well with the general observations found in many studies in which pronghorns were usually found to be browsers. Cacti are utilized in some quantities before and after germination of most of the forbs. Gaura/Camissonia and Dalea mollis were taken in the greatest relative densities. Gaura and Camissonia, two genera in the evening primrose family, are indistinguishable with the microscopic technique employed. These genera were very important in February and March, Life History - 1 (DRAFT) - Life History Species PRONGHORN, SONORAN Species Id ESIS052001 Date 14 MAR 96 decreasing in importance in April. Dalea mollis was the most important in April through June, with some fragments still present in the feces in September. D. mollis is a mat-forming forb that grows on rocky soils and remains green for a relatively long period. Pronghorn were observed feeding on it in May and September. Kallstroemia californica and Tidestromia lanuginosa were forbs highly utilized during the fall. Euphorbia spp. was taken in April, May, and September in significant quantities. The species of Euphorbia found in the fecal material were mat formers and were often abundant when other forbs were not. The ubiquitous and exotic Plantago insularis was utilized in the greatest quantities in February through March. Many different shrub species were important throughout the year. Krameria spp. was found mostly in feces collected in January, yet was present throughout the year in smaller quantities. Both honey mesquite and mistletoe (Phoradendron californicum) were important in January and October. The latter is a plant parasite that often grows on honey mesquite and paloverde in large quantities. Pronghorn were observed eating mistletoe several times. Paloverde was present in all months' samples. Hymenoclea monogyra was utilized from February to May but was taken most in March. Eriogonum spp. was used throughout the year. Several species of Eriogonum are abundant in the Cabeza Prieta, and the pronghorn may utilize some of each. Ambrosia dumosa was important in February and April. Opuntia spp. was important in summer and winter. Although it is difficult to determine microscopically, much of the cholla present in the feces may be the fruits of chain cholla. The fruits are persistent and may provide food when little else is available. Cacti may not be utilized when forbs are available. No opuntia was found in the October samples from Mexico. Possibly forbs were in lesser abundance in Mexico where the pronghorn's range is also grazed by livestock. Pronghorn on Cabeza Prieta NWR appear to select for forbs when they are available. They still take forbs in some quantity in each month studied so they must consume some dried and withered forbs when green forbs are not available. Shrubs and cacti are utilized most heavily during the dry months when the annual forbs are less plentiful. After winter rains, an abundance of annuals appears in the late winter and early spring, which pronghorn extensively utilize (11). Much more information is needed, and should be forthcoming from an intensive study being undertaken by the Arizona Game and Fish in the fall of 1983 with joint funding from U.S. Fish and Wildlife Service, Department of Air Force, Arizona Game and Fish Department, and Chicar Safari Foundation (06). Sonoran pronghorn's ability to vary their diet with food availability enables them to survive in the dry desert environment. The large number of plant species consumed attests to this ability, and indicate the opportunistic nature of the Sonoran pronghorn (11). HOME RANGE/TERRITORY: No information is available on home range. Radio-collared pronghorn will be used in the upcoming major study to better understand Sonoran pronghorn movements and seasonal use of the available habitats (06). Life History - 2 (DRAFT) - Life History Species PRONGHORN, SONORAN Species Id ESIS052001 Date 14 MAR 96 In contrast to the northern subspecies of pronghorn, the Sonoran pronghorn does not congregate in large groups at any time of the year. This may be a survival response to marginal habitat. Many small groups are better able to ensure the survival of the population during periods of high mortality. If small herds are lost throughout the range, no reduction or shrinking of occupied habitat occurs. However, if large herds are lost, significant areas of range are vacated and may not be reoccupied. Small herds would also be better able to utilize limited food resources (11). PERIODICITY: Sonoran pronghorn are basically crepuscular, particularly during the heat of May, June, and July, when shaded air temperatures reach 120 degrees F while ground temperatures reach 180 degrees F (11). There are seasonal movements of pronghorn to areas with good forb production in spring and fall (11). MIGRATION PATTERNS: Seasonal movements have been noted but not fully understood. Radiotelemetry studies to be started in the fall of 1983 will provide much needed information in this area (06). COVER/SHELTER REQUIREMENTS: Sonoran pronghorn lie in shaded places during the heat of the day (11). Further information needed and upcoming from pending research (06). REPRODUCTIVE SITE REQUIREMENTS: Information is needed on seasonal movements to determine where Sonoran pronghorn are during the breeding season (06). REPRODUCTIVE CHARACTERISTICS: Birth normally occurs during the first or second week of March. The earliest fawn observed was seen on 7 March 1980 and was judged to be less than a week old using Einarsen's (13) criteria. Fawns judged to be less than a month old have been observed as late as mid-April (11). Assuming the gestation period of the Sonoran pronghorn to be 240 days, identical to that published for A. a. americana (14), peak breeding activity would occur about the first week of July. Information on breeding behavior, i.e., harems, territories (15), is presently not available (06). PARENTAL CARE: Until more is known, it must be assumed that parental (mother) care in Sonoran pronghorn is similar to that described for A. a. americana (14,15). POPULATION BIOLOGY: Nelson (16) estimated a Sonoran pronghorn population of 595 in Sonora and 105 in Arizona in 1925. Nichol (17) estimated 60 antelope in southwestern Arizona in 1941 not including those found on the Organ Pipe Cactus National Monument. Halloran (18) said there were probably less than 100 Sonoran pronghorn in 1956. Villa (19) Life History - 3 (DRAFT) - Life History Species PRONGHORN, SONORAN Species Id ESIS052001 Date 14 MAR 96 estimated over 1000 antelope in northwestern Mexico in 1957. The 1968 population estimate for Sonoran pronghorn in Arizona was 50 (07). Observations compiled by personnel of the Arizona Game and Fish Department over 10 years (approx. 1973-1983) indicate a population in Arizona of more than 50 but less than 150. The population in Mexico in 1983 was believed to number between 200-350 (11). In a 1985 report by the Instituto de Ecologia, AC to Direccion de Flora/Fauna Terrestres, EDUE in Mexico they estimated the population range was 33-93 Sonoran pronghorn in Mexico with 63 being the mean estimate (22). The coyote (Canis latrans) is the major predator in Sonoran pronghorn habitat. Simmons (20) examined 580 coyote fecal deposits from Cabeza Prieta NWR for ungulate remains. Five, less than 0.8 percent, contained pronghorn remains. Although low, this predation rate could be a limiting factor when considering a population comprised of only 100-150 individuals. During the 1960's the refuge was subject to intensive predator control using compound 1080 with no recorded benefit on the pronghorn population. Three instances of mortality have been recorded; one buck fawn drowning in the Wellton-Mohawk canal in 1970 (an adult buck was rescued and released in 1979), a road killed doe in Mexico in 1975, and a dead mature buck (cause unknown) found on the Organ Pipe Cactus National Monument in 1972. Also, in 1969, 4 Sonoran pronghorn skulls of unknown origin were seized by U.S. Fish and Wildlife agents from a Tucson, AZ taxidermist (11). The goal of the recovery plan is a population of 300 pronghorn in Arizona (5 year average), or whatever is feasible for the habitat if research proves the carrying capacity to be less than 300. SPECIES INTERRELATIONSHIPS: In addition to the coyote (as described above in "POPULATION BIOLOGY"), bobcats (Lynx rufus), mountain lions (Felis concolor), and golden eagles (Aguila chrysaetos), are all known predators of pronghorn and occur in Sonoran pronghorn habitat. OTHER LIFE HISTORY DESCRIPTORS: None. Life History - 4
                           (DRAFT) - Management Practices
                             Species PRONGHORN, SONORAN
                                Species Id ESIS052001
                                   Date 14 MAR 96



MANAGEMENT PRACTICES

RESULT MANAGEMENT PRACTICE Beneficial Controlling/Restricting Off-Road Vehicles Beneficial Restricting/regulating human disturbance of populations Beneficial Controlling/Restricting Road Maintainance Actions Beneficial Land Acquisition Beneficial Stocking captive-reared wild-strain animals Beneficial Transplanting wild animals Beneficial Restricting Poaching Beneficial Controlling/Removing Domestic Animals Adverse Poaching Existing Poaching Adverse Sport Hunting/Fishing Existing Sport Hunting/Fishing Adverse Irrigating Existing Irrigating Adverse Grazing Existing Grazing Adverse Existing Adverse Vegetation Composition Changes Existing Vegetation Composition Changes COMMENTS ON MANAGEMENT PRACTICES - The Sonoran pronghorn has become endangered as a result of losses in habitat and numbers. A unique and poorly understood member of the fauna associated with the Sonoran desert, the Sonoran pronghorn is one of the few large mammals recognized as being endangered in the United States today. Several reasons have been presented for this decline. The most popular is over-hunting. Unregulated hunting undoubtedly contributed to the initial decline; however, with the protection that has existed for the past 40 years the pronghorn should have recovered if hunting was indeed the primary factor. The probable reason for the decline is loss of habitat. The drying of major rivers and overgrazing significantly altered Sonoran pronghorn habitat in southwestern Arizona by the 1930's. Why these rivers dried is a major study in itself; but briefly, this resulted partly from heavy overgrazing which speeded up runoff. Also, pumping of ground water to support large irrigation projects near these rivers lowered the water table, thus reducing the flow. However, the death blow to the Gila River was the numerous, large dams built on the upper drainage systems to support irrigation and power projects and to satisfy the water needs of a multiplying human population (21). This habitat has yet to recover despite the fact that most of the area is made up of three large public land withdrawals (Cabeza Prieta NWR, Organ Pipe Cactus National Monument, and Barry M. Goldwater Gunnery Range). The only significant loss of habitat in recent years in Arizona occurred on the Papago Reservation where severe overgrazing by cattle coupled with recurrent drought resulted in the loss of large areas Management Practices - 1 (DRAFT) - Management Practices Species PRONGHORN, SONORAN Species Id ESIS052001 Date 14 MAR 96 of pronghorn habitat. It is believed that economic exploitation of habitat (grazing, agriculture) and that poaching still cause numerical and habitat losses in Mexico (03). APPROVED PLAN: U.S. Fish and Wildlife Service. 1982. Sonoran Pronghorn Recovery Plan. U.S. Fish and Wildl. Serv., Albuquerque, NM. 20 pp. The primary objective of the recovery plan is to maintain existing numbers and distribution of Sonoran pronghorn while developing techniques which will result in a U.S. population of 300 animals (average for a five year period) or numbers determined feasible for the habitat. This will be accomplished by first undertaking an intensive study of the ecology of the subspecies from which will be determined such things as home range, distribution, natality, mortality. If the population can be raised to 300 (or feasible number for habitat) in the existing habitat, it can be downlisted without transplants. If the studies indicate limiting factors that can be modified, such as water or food distribution, predation, human disturbance, etc., management efforts will be directed at them. The historic range will also be surveyed for possible transplant sites, if necessary, and the transplanted population and habitat will be monitored until determined successful. Existing herds will also be continually monitored (01). A step-down outline of recovery of the species follows: 1. Maintain present population. A) Monitor U.S. population. B) Assist Mexico in monitoring the Mexico population. C) Protect and manage known antelope habitat. D) Determine taxonomic status. 2. Increase existing population. A) Determine life history. B) Determine natality. C) Investigate inter- and intra-specific competition. D) Ascertain biological parameters. 3. Increase population within existing habitat to numbers determined feasible. A) Modify limiting factors as identified 1. Predator control 2. Increase food supply (by habitat manipulation) 3. Increase water supply (by controlling current water levels and flows, and by construction of watering holes) 4. Reduce effect of disease and parasites 5. Minimize human disturbance a. Modify fencing b. Control access c. Control poaching d. Reduce harassment e. Contain development f. Discourage increased human use Management Practices - 2 (DRAFT) - Management Practices Species PRONGHORN, SONORAN Species Id ESIS052001 Date 14 MAR 96 6. Eliminate permit and trespass livestock grazing B) Establish captive breeding population to provide transplant stock. 4. Reestablish in historic habitat (by transplanting wild and captive breed individuals). Management Practices - 3
                                   (DRAFT) - References
                                Species PRONGHORN, SONORAN
                                  Species Id ESIS052001
                                      Date 14 MAR 96



     

References

*****REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE***** 01 Goldman, E.A. 1945. A new pronghorn antelope from Sonora. Proc. Biol. Soc. Washington. 58:3-4. 02 Paradiso, J.L. and R.M. Nowak. 1971. Taxonomic status of the Sonoran pronghorn. J. Mamm. 52:855-858. 03 U.S. Fish and Wildlife Service. 1982. Sonoran Pronghorn Recovery Plan. U.S. Fish and Wildl. Serv., Albuquerque, NM. 20 pp. 04 Shreve, F. and I.L. Wiggins. 1964. Vegetation and flora of the Sonoran Desert. Vol. I. Stanford Univ. Press, Palo Alto, CA. 05 Sellers, W.D. and R.H. Hill. 1973. Arizona climate 1931-72. U. Arizona Press, Tucson. 06 Carley, C. 1983. Pers. comm. U.S. Fish and Wildl. Serv. Albuquerque, NM 87103. 07 Monson, G. 1968. The desert pronghorn. The Desert Bighorn Council 1968 Transactions. 08 Lumholtz, K.S. 1912. New trails in Mexico. Charles Scribner's Sons, New York, NY. 09 Hornaday, W.T. 1908. Camp-fires on desert and lava. Charles Scribner's Sons, New York, NY. 10 Carr, J.N. 1970. Endangered species investigations: Sonoran pronghorn. Arizona Game and Fish Dept. Project W-53-21, Work Plan 8, Job 1. Phoenix, AZ. 11 Arizona Game and Fish Department. 1981. The Sonoran pronghorn. Special Rept. 10. 54 pp. 12 Beuchner, H.K. 1950. Life history, ecology, and range use of the pronghorn antelope in Trans-Pecos, Texas. Am. Mid. Nat. 43: 257-354. 13 Einarsen, A.S. 1948. The pronghorn antelope and its management. Wildl. Manage. Inst., Wash.,D.C. 14 Asdell, S.A. 1946. Patterns of mammalian reproduction. Comstock Publ. Co., Ithaca, NY. 15 Kitchen, D.W. 1974. Social behavior and ecology of the pronghorn. Wildl. Mono. 38. 16 Nelson, E.W. 1925. Status of the pronghorn antelope, 1922-1924. USDA Bull. 1346:64. 17 Nichol, A.A. 1941. Game reconnaissance of southwestern Arizona, south of the Gila River. Unpubl. File Rept., Arizona Game and Fish Dept., Yuma, AZ. 18 Halloran, A.P. 1957. A note on the Sonoran pronghorn. J. Mamm. 38:423. 19 Villa, R.B. 1958. Partial report of Prof. Bernardo Villa R. concerning an investigation of wild sheep And antelope in northern Mexico in the first quarter of 1958. 7 pp. 20 Simmons, N.M. 1969. The social organization, behavior, and environment of the desert bighorn sheep on the Cabeza Prieta Game Range, Arizona. Unpubl. Ph.D. Diss., Univ. Arizona, Tucson. 21 New Mexico Department of Game and Fish. 1972. Symposium on: Rare and endangered wildlife of the southwestern United States, September 22-23, 1972, Albuquerque, NM. NM Dept. of Game and Fish, Santa Fe. References - 1 (DRAFT) - References Species PRONGHORN, SONORAN Species Id ESIS052001 Date 14 MAR 96 22 Gonzales-Romero, A., and La Fon Terravas, A. 1985. Present status of Pronghorn "Antilocapra americana" in Mexico: a 1985 survey. Organ Pipe Cactus Natl. Monument, AZ. 30 pp. *****REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY***** 01 U.S. Fish and Wildlife Service. 1982. Sonoran Pronghorn Recovery Plan. U.S. Fish and Wildl. Serv., Albuquerque, NM. 17 pp. 02 Davis, G.P. 1973. Man and wildlife in Arizona; the presettlement era, 1823-1864. M.S. Thesis, U. Ariz., Tucson. 03 Hall, R.E., and K.R. Kelson. 1959. The mammals of North America. The Ronald Press, New York, NY. References - 2