Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
OBSERVATIONS ON THE ECOLOGY OF THE ENDEMIC MEARNS'S SQUIRREL (TAMIASCIURUS MEARNSI) Author(s) :John L. Koprowski, Nicolás Ramos, Bret S. Pasch, and Claire A. Zugmeyer Source: The Southwestern Naturalist, 51(3):426-430. 2006. Published By: Southwestern Association of Naturalists DOI: http://dx.doi.org/10.1894/0038-4909(2006)51[426:OOTEOT]2.0.CO;2 URL: http://www.bioone.org/doi/full/10.1894/0038-4909%282006%2951%5B426%3AOOTEOT %5D2.0.CO%3B2 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. 426 vol. 51, no. 3 The Southwestern Naturalist OBSERVATIONS ON THE ECOLOGY OF THE ENDEMIC MEARNS’S SQUIRREL (TAMIASCIURUS MEARNSI) JOHN L. KOPROWSKI,* NICOLÁS RAMOS, BRET S. PASCH, AND CLAIRE A. ZUGMEYER Wildlife Conservation and Management, School of Natural Resources, University of Arizona, Tucson, AZ 85721 *Correspondent: [email protected] ABSTRACT Mearns’s squirrel (Tamiasciurus mearnsi) is an endemic species of the montane forest of the Sierra de San Pedro Mártir in Baja California. Despite having been described for the first time in 1893 and a listing as threatened by Mexican authorities, no information is available on the ecology of this southernmost Tamiasciurus. We observed the ecology of Mearns’s squirrels during 2004 and 2005. Mearns’s squirrel apparently does not form larderhoards, known as middens, or leaf nests commonly built by other members of this genus. We observed Mearns’s squirrels to feed heavily on tree seeds and fungi. We noted males with scrotal testes and a female in estrus in late spring. We did not observe eastern gray squirrels (Sciurus carolinensis), introduced to the western Sierra in 1946, within the areas that we searched for T. mearnsi. Mearns’s squirrels might possess unique adaptations for their persistence in the dry, open forest of the Sierra de San Pedro Mártir. RESUMEN La ardilla de San Pedro Mártir (Tamiasciurus mearnsi) es una especie endémica del bosque de montaña de la Sierra de San Pedro Mártir en Baja California. A pesar de haber sido descrita por primera vez en 1893 y a que se encuentra catalogada como amenazada por las autoridades mexicanas, no hay información disponible sobre la ecologı́a de esta Tamiasciurus más austral. Observamos la ecologı́a de las ardillas de San Pedro Mártir durante 2004 y 2005. La ardilla San Pedro Mártir parece no formar cúmulos de comida conocidos como basurales, o nidos de hoja comúnmente construidos por otros miembros de este género. Observamos a las ardillas de San Pedro Mártir alimentarse principalmente de las semillas de los árboles y de hongos; notamos machos con testı́culos escrotados y una hembra en celo a finales de la primavera. No observamos a las ardillas Sciurus carolinensis, introducidas en la parte oeste de la Sierra en 1946, dentro de las áreas donde buscamos a las T. mearnsi. Las ardillas de San Pedro Mártir pueden poseer adaptaciones únicas para su persistencia en el bosque abierto y seco de la Sierra de San Pedro Mártir. Conservation of endemic organisms presents one of the greatest challenges for ecologists. Northwestern Mexico possesses one of the most diverse floras and faunas in the world, in part due to the montane sky islands that often harbor endemics (Turner et al., 1995; Koprowski, 2005a). Fauna of peninsular Baja California is especially distinct given a long evolutionary history in isolation (e.g., Welsh, 1988; Hafner and Riddle, 1997). In many cases, knowledge of peninsular endemics, especially montane species, is extremely poor. The Mearns’s squirrel (Tamiasciurus mearnsi) in the Sierra de San Pedro Mártir of Baja California, Mexico (Wilson and Cole, 2000) is one such example. Mearns’s squirrels are closely related to Douglas’s squirrels (T. douglasii) in the Sierra Nevada of California, USA, with specific status contentious (Lindsay, 1981; Arbogast et al., 2001). Not a single ecological paper has been published on Mearns’s squirrels despite over 100 years since the species was first described (Allen, 1893; Townsend, 1897); it currently is listed as threatened under Mexican law (Ceballos et al., 2002). The basic ecology of Mearns’s squirrel such as diet, habitat, and reproduction is poorly known (Yensen and Valdés-Alarcón, 1999) other than that inferred from distributional and comparative anatomical and genetic studies (Lindsay, 1981; Arbogast et al., 2001). In addition, the introduction of eastern gray squirrels (Sciurus carolinensis) in 1946 might pose a threat (Huey, 1964) as evidenced in other countries where intentional releases have occurred (Gurnell, 1987). Herein, we present observations on the reproduction, food habits, vocalizations, and interspecific interactions of Mearns’s squirrels. September 2006 Notes Our study area was the 65,000-ha Parque Nacional Sierra de San Pedro Mártir located about 100 km east of San Telmo, Baja California, Mexico. Open forested parklands (Minnich et al., 2000) at elevations above 2,100 m are dominated by Jeffrey pine (Pinus jeffreyi), lodgepole pine (P. contorta), ponderosa pine (P. ponderosa), sugar pine (P. lambertiana), and white fir (Abies concolor). We visited forests in the Vallecitos, La Corona de Abajo, Arroyo Los Alamillos, La Grulla, and La Zanja areas of the national park during 4 to 7 November 2004 and 16 to 20 March, 23 to 24 April, and 19 to 24 May 2005. We visually assessed all trees and surrounding ground cover within the open forests of our study sites on foot in search of Mearns’s squirrels as well as sign, including leaf nests (Young et al., 2002) and larderhoards of cones known as middens (Finley, 1969) that typically indicate the presence of Tamiasciurus. The open forest structure and a paucity of downed trees (Stephens and Gill, 2005) greatly facilitated observations. Once we located an individual, we noted its behavior and attempted to determine sex and reproductive condition from external genitalia. We observed Mearns’s squirrels (Fig. 1) on 17 occasions (5 female, 6 male, 6 unknown sex) in the Vallecitos and Arroyo Los Alamillos areas as we surveyed approximately 4,000 ha of forest. Notably, we did not detect any middens or leaf nests during our surveys. Tamiasciurus hudsonicus can nest in cavities or burrows (Yahner, 1980; Young et al., 2002), and the large number of overmature trees and snags (Stephens and Gill, 2005) might permit reliance on such nest types. Furthermore, T. mearnsi seems not to rely on larderhoards of cones. Other Tamiasciurus are known to scatterhoard and larderhoard food items in logs or snags (reviewed in Gurnell, 1987; Steele, 1998, 1999). Tamiasciurus hudsonicus scatterhoard where food types or environmental conditions are not conducive to midden formation and maintenance (Hurly and Robertson, 1986). Lack of larderhoards could reflect the xeric conditions inhabited by this southernmost member of Tamiasciurus (Lindsay, 1981), where cool moist conditions that retard cone opening (Smith, 1968) might not occur. All male squirrels that we observed possessed scrotal testes (1 male on 20 May, 1 male on 21 May, 4 males on 22 May 2005). One fe- 427 male Mearns’s squirrel possessed an enlarged pink vulva and was pursued by 2 or possibly 3 males on 22 May 2005 in a mating chase. Our scant observations on reproductive males and female in late spring suggest similarity with other Tamiasciurus (Steele, 1998, 1999). In particular, the similarly isolated and endangered Mount Graham red squirrel (T. hudsonicus grahamensis) of southern Arizona can breed in the spring and summer (Koprowski, 2005b). Mearns’s squirrels were observed feeding on cones of the current year of Jeffrey pine (2 females, 2 males) and white fir (1 male), branch tips of white fir (1 female), and basidiomycete fungi, veiled polypores (Cryptoporus volvatus), found on the upper trunk of white fir (2 females, 3 males). Feeding sign on Jeffrey pine was found commonly in areas that we visited, with the exception of La Zanja. Other Tamiasciurus also feed heavily on fungi, conifer seed, and conifer branch tips during spring and early summer (Steele, 1998, 1999). At least 6 distinct vocalizations are known from Tamiasciurus (Gurnell, 1987). We discerned 3 calls based on our observations. On 3 occasions (1 male, 2 unknown sex), we heard a call similar to the territorial ‘‘rattle’’ of T. hudsonicus and T. douglasii (Smith, 1978) but of seemingly higher pitch. Mearns’s squirrels also gave a ‘‘chirp’’ call (Smith, 1978) on 3 occasions (2 females, 1 male) when aggravated and a woofing bark or ‘‘buzz’’ call (Smith, 1978) when startled or mildly aggravated (1 female, 1 male). We observed 4 interspecific interactions. On 7 November 2004, a red-tailed hawk (Buteo jamaicensis) chased a T. mearnsi through the canopy of sugar and lodgepole pines for ⬍10 s before disappearing from sight. Western bluebirds (Sialia mexicana) mobbed a solitary adult female Mearns’s squirrel on 2 occasions (20 and 22 May 2005). Lastly, we observed a coyote (Canis latrans) passing under a tree where a Mearns’s squirrel rested 8 m aboveground on 22 May 2005. This elicited only a raised head from the adult male squirrel. Mearns’s squirrels seem to be uncommon and reclusive in the Sierra de San Pedro Mártir. Most biologists have referred to the species as occurring in low densities (Leopold, 1959; Huey, 1964; Yensen and Valdés-Alarcón, 1999). Our brief observations on the ecology of T. mearnsi suggest that some aspects of their bi- 428 The Southwestern Naturalist vol. 51, no. 3 September 2006 Notes ology, such as food habits, reproduction, and vocalizations, are similar to those of other members of Tamiasciurus (Steele, 1998, 1999). However, absence of obvious larderhoards and leaf nests indicates that Mearns’s squirrels might have unique adaptations to dry and open forests of this southernmost extension of the genus Tamiasciurus. Eastern gray squirrels were introduced at La Zanja and Arroyo San Rafael on the western slopes of the Sierra de San Pedro Mártir in 1946 (Yensen and Valdéz-Alarcón, 1999). However, we did not observe any individuals or sign during our visit to La Zanja. The last report of eastern gray squirrels at La Zanja is from 1956 (Huey, 1964). We were not able to assess the status of eastern gray squirrels in Arroyo San Rafael. Our observations suggest the need for research into several aspects of the ecology of T. mearnsi. The significance of the lack of middens and leaf nests must be assessed to elucidate important selective pressures faced by Mearns’s squirrels. Because these conspicuous signs of squirrel presence are not available, census techniques must be developed to effectively monitor population status of T. mearnsi. Furthermore, investigation of the status of introduced eastern gray squirrels is necessary to formulate conservation strategies for the endemic Mearns’s squirrel. We thank the Desert Southwest Cooperative Ecosystem Studies Unit, the Intermountain Region International Conservation Office (IMRICO) of the National Park Service, and the Arizona Agricultural Experiment Station for funding. The Consejo Nacional de Ciencia y Tecnologı́a (CONACYT) provided a scholarship to Nicolás Ramos (158208). L. Norris, D. Swann, and N. Kline of the National Park Service in the United States and W. Zúñiga, Á. López, and M. Valles of the Parque Nacional Sierra de San Pedro Mártir supported the concept of the project. J. Franco, P. Strittmatter, B. Powell, J. Sasian, J. Bohigas, D. Hiriart, D. Carrasco, A. Garcia, I. González, and E. Valdés facilitated housing logistics at Observatorio Astronómico Nacional (UNAM). W. Shaw and R. Mannan assisted with fieldwork. L. Bojór- 429 quez, S. Stephens, R. Minnich, J. Vargas, C. Porras, E. Meling, E. Mellink, E. Salgado, B. Mackintosh, and G. Mackintosh graciously shared their knowledge of the Sierra. Research was conducted under permits from Dirección Forestal y de la Fauna Parque Nacional Sierra de San Pedro Mártir, Dirección General de Vida Silvestre (SEMARNAT), and the Institutional Animal Care and Use Committee, University of Arizona. LITERATURE CITED ALLEN, J. A. 1893. On a collection of mammals from the San Pedro Mártir region of Lower California, with notes on other species, particularly of the genus Sitomys. Bulletin of the American Museum of Natural History 5:181–202. ARBOGAST, B. S., R. A. BROWNE, AND P. D. WEIGL. 2001. Evolutionary genetics and Pleistocene biogeography of North American tree squirrels (Tamiasciurus). Journal of Mammalogy 82:302– 319. CEBALLOS, G., J. ARROYO-CABRALES, AND R. A. MEDELLı́N. 2002. The mammals of Mexico: composition, distribution, and conservation status. Occasional Papers, Museum of Texas Tech University 218:1–28. FINLEY, R. B. J. 1969. Cone caches and middens of Tamiasciurus in the Rocky Mountain region. Miscellaneous Publications, University of Kansas Museum of Natural History 51:233–273. GURNELL, J. 1987. The natural history of squirrels. Facts on File, New York. HAFNER, D. J., AND B. R. RIDDLE. 1997. Biogeography of Baja California peninsular desert mammals. In: T. L. Yates, W. L. Gannon, and D. E. Wilson, editors. Life among the muses: papers in honor of James S. Findley. Museum of Southwestern Biology, University of New Mexico, Albuquerque. Pages 39–68. HUEY, L. M. 1964. The mammals of Baja California, Mexico. Transactions of the San Diego Society of Natural History 13:85–168. HURLY, T. A., AND R. J. ROBERTSON. 1986. Scatterhoarding by territorial red squirrels: a test of the optimal density model. Canadian Journal of Zoology 65:1247–1252. KOPROWSKI, J. L. 2005a. Management and conservation of tree squirrels: the importance of endemism, species richness, and forest condition. In: G. Gottfried, B. Gebow, L. Eskew, and C. Ed- ← FIG. 1 An adult female Mearns’s squirrel (Tamiasciurus mearnsi) descending a white fir (Abies concolor) on 22 May 2005, Parque Nacional Sierra de San Pedro Mártir, Baja California, Mexico. Photograph by B. S. Pasch. 430 The Southwestern Naturalist minster, editors. Connecting mountain islands and desert seas: biodiversity and management of the Madrean Archipelago II. RMRS-P-36. U.S. Department of Agriculture Forest Service, Rocky Mountain Research Station, Fort Collins, Colorado. Pages 245–250. KOPROWSKI, J. L. 2005b. Annual cycles in body mass and reproduction of endangered Mt. Graham red squirrels. Journal of Mammalogy 86:309–313. LEOPOLD, A. S. 1959. Wildlife of Mexico. University of California Press, Berkeley. LINDSAY, S. L. 1981. Taxonomic and biogeographic relationships of Baja California chickarees (Tamiasciurus). Journal of Mammalogy 62:673–682. MINNICH R. A, M. G. BARBOUR, J. H. BURK, AND J. SOSA-RAMÍREZ. 2000. Californian mixed-conifer forests under unmanaged fire regimes in the Sierra San Pedro Mártir, Baja California, Mexico. Journal of Biogeography 27:105–129. SMITH, C. C. 1968. The adaptive nature of social organization in the genus of tree squirrels Tamiasciurus. Ecological Monographs 38:31–63. SMITH, C. C. 1978. Structure and function of the vocalizations of tree squirrels (Tamiasciurus). Journal of Mammalogy 59:793–808. STEELE, M. A. 1998. Tamiasciurus hudsonicus. Mammalian Species 586:1–9. STEELE, M. A. 1999. Tamiasciurus douglasii. Mammalian Species 630:1–8. STEPHENS, S. L., AND S. J. GILL. 2005. Forest structure and mortality in an old-growth Jeffrey pine-mixed conifer forest in northwestern Mexico. Forest Ecology and Management 205:15–28. TOWNSEND, C. H. 1897. Descriptions of a new eagle from Alaska and a new squirrel from Lower Cal- vol. 51, no. 3 ifornia. Proceedings of the Biological Society of Washington 11:145–146. TURNER, D. S., S. BRANDES, M. FISHBEIN, AND P. W. HIRT. 1995. Preserve design for maintaining biodiversity in the sky island region. In: L. F. DeBano, P. F. Ffolliott, A. Ortega-Rubio, G. J. Gottfried, R. H. Hamre, and C. B. Edminster, editors. Biodiversity and management of the Madrean Archipelago: the sky islands of southwestern United States and northwestern Mexico. U.S. Department of Agriculture Forest Service, GTR RM-264, Fort Collins, Colorado. Pages 524–530. WELSH, H. H. 1988. An ecogeographic analysis of the herpetofauna of the Sierra San Pedro Mártir Region, Baja California, with a contribution to the biogeography of the Baja California herpetofauna. Proceedings of the California Academy of Sciences 46:1–72. WILSON, D. E., AND F. R. COLE. 2000. Common names of mammals of the world. Smithsonian Institution Press, Washington, D.C. YAHNER, R. H. 1980. Burrow system use by red squirrels. American Midland Naturalist 103:409–411. YENSEN, E., AND M. VALDÉS-ALARCÓN. 1999. Family Sciuridae. In: S. T. Álvarez-Castañeda and J. L. Patton, editors. Mamı́feros del Noroeste de México. Centro de Investigaciones Biológicas del Noroeste, S.C., México. Pages 239–320. YOUNG, P. J., V. L. GREER, AND S. K. SIX. 2002. Characteristics of bolus nests of red squirrels in the Pinaleño and White mountains of Arizona. Southwestern Naturalist 47:267–275. Submitted 28 June 2005. Accepted 9 December 2005. Associate Editor was Philip D. Sudman. RECENT RECORDS OF DESERT BIGHORN SHEEP (OVIS CANADENSIS MEXICANA) IN EASTERN SONORA AND NORTHWESTERN CHIHUAHUA, MEXICO KARLA PELZ-SERRANO, EDUARDO PONCE-GUEVARA, RODRIGO SIERRA-CORONA, RURIK LIST, AND GERARDO CEBALLOS* Universidad Autónoma de Querétaro, Facultad de Ciencias Naturales. Cerro de las Campanas sin número, Col. Niños Héroes, Querétaro, CP 76010, México (KP-S, EP-G, RS-C) Instituto de Ecologı́a, UNAM, A.P. 70-275, México D.F. 04510, México (KP-S, EP-G, RS-C, RL, GC) *Correspondent: [email protected] ABSTRACT The desert bighorn sheep (Ovis canadensis mexicana) was extirpated from most of its range in northern Mexico and the southwestern United States by the 1980s. Several populations have been established through reintroductions in both countries, but none in the Chihuahua– Sonora border region, where we report here 3 recent records. These records suggest the possibility September 2006 Notes 431 of reintroducing bighorn sheep in northwestern Chihuahua and northeastern Sonora to increase the long-term viability of the species in the region. RESUMEN El borrego cimarrón (Ovis canadensis mexicana) fue extirpado de la mayor parte de su área de distribución en el norte de México y el suroeste de los Estados Unidos hacia la década de 1980. Mediante reintroducciones, se han establecido varias poblaciones en ambos paı́ses, pero ninguna en la región fronteriza entre Chihuahua y Sonora, de donde se reportan 3 registros en esta nota, indicando la posibilidad de reintroducir al borrego cimarrón en el noroeste de Chihuahua y noreste de Sonora para incrementar la viabilidad a largo plazo de la especie en al región. The desert bighorn sheep (Ovis canadensis mexicana) was once distributed from southern Canada to northern Mexico, along the main mountain massifs of western North America (Hall, 1981). For more than a century, desert bighorns have been one of the main species for trophy-hunting in North America, and thus, subject to legal and illegal hunting that, coupled with competition with cattle, diseases from cattle, and habitat fragmentation, decreased bighorn distribution to small and often isolated groups in inaccessible areas (Leopold, 1959; Smith and Krausman, 1988; Krausman et al., 1999; Guerrero et al., 2003). The species is listed as under special protection in Mexico (SEMARNAP, 2002) and threatened in the USA (Rubin, 1998; New Mexico Game and Fish Department, 2002). Recovery efforts in Mexico have centered on the establishment of reintroduced populations within the former geographic range, conservation of original habitat, and provision of incentives to conservation by promoting sustainable hunting. A well-known example of a successful recovery program is that on Tiburón Island (Sonora), where scientists from the National University of Mexico and non-governmental organizations organized a solid hunting program that has provided the Seri Indians, owners of the island, incentives to become wardens of both the sheep and its habitat (Medellı́n et al., 1999, 2005). The historical distribution of O. c. mexicana in Mexico included the Baja California Peninsula, Sonora, Chihuahua, and Coahuila (Leopold, 1959; Hall, 1981). In the southwestern United States, desert bighorn sheep were found in California, eastern Arizona, and New Mexico (Hall, 1981; Shackleton, 1985; Hoffmeister, 1986). It was estimated that a million bighorn sheep historically inhabited the arid environments of the United States, but by 1980, the total population was approximately 12,000 individuals (Smith and Krausman, 1988). This critical decline prompted reintroduction efforts in Arizona, New Mexico, California, Colorado, Texas, Utah, and Nevada to recover populations across the historical range (Lee, 1999; New Mexico Game and Fish Department, 2002). In 1998, larger populations were reported in southwestern Arizona, and isolated populations in the Peloncillo and Catalinas mountains of Arizona (Lee, 1999). In 2002, small but relatively stable populations were reported in the Red Rock Wildlife Area, the Ladron Mountains (26 individuals), the Peloncillo Mountains (30 individuals), the Fra Cristobal Mountains (66 individuals), and the Big Hatchet Mountains (40 individuals) (New Mexico Game and Fish Department, 2002). Presently, desert bighorn sheep in Mexico survive in the Baja California Peninsula and Sonora, but they have been extirpated from Chihuahua and Coahuila (Rubin et al., 1998; Medellı́n et al., 1999, 2005; Hayes et al., 2000; Guerrero et al., 2003). There are ongoing efforts to reintroduce the species in the Maderas del Carmen region of Coahuila (P. Robles Gil, pers. comm.) and in the municipality of Coyame in eastern Chihuahua (R. Uranga, pers. comm.). Herein, we suggest that reintroductions of O. c. mexicana to northwestern Chihuahua or northeastern Sonora might create a metapopulation with populations in southwestern New Mexico or southeastern Arizona, increasing viability of desert bighorn in the region. We have 2 recent reports of bighorn sheep in northwestern Chihuahua by local people (Fig. 1). The first report was in 1995, when a male was hunted by local cowboys working at an unspecified location at Las Palmas Ranch, a 30,000-ha property that borders New Mexico, just south of the Alamo Hueco Mountains and 27.8 km south from the nearest known population of bighorns in the Big Hatchet Mountains. In 2002, a male was seen 432 The Southwestern Naturalist vol. 51, no. 3 FIG. 1 Distribution of desert bighorn sheep (Ovis canadensis mexicana) in the southwestern USA and northwestern Mexico, including historical and current distribution, and new records (modified from Hall, 1981; Leopold, 1985; Shackleton, 1985; Hoffmeister, 1986; Lee, 1999; New Mexico Department of Game and Fish, 2002). crossing Federal Highway 2 ( Janos–Asención) near La Lagunita ( J. Harris, pers. comm.), 68 km southeast from the closest population in the Big Hatchet Mountains. The dominant vegetation in that area is desertscrub, with low plant density. To these we add our own sighting of a male bighorn on Los Ojos Ranch, Sonora, on 4 August 2003. We estimated this ram to be 6 to 8 years old, according to criteria defined by Smith and Krausman (1988). Los Ojos Ranch is private property from which cattle were removed in 1998; the ranch currently is used for habitat conservation and restoration. The ram September 2006 Notes climbed a rocky slope, crossed the road we were driving, climbed another escarped slope, and descended to a rocky canyon. This sighting was 5.7 km south of the Arizona-Sonora border (UTMs 12R 0690985 E, 3436038 N), 33.5 km south from the nearest known population of bighorn sheep in the Peloncillo Mountains of Arizona. We saw this individual at a location near 2 artificial ponds and a permanent arroyo, in interior chaparral and thornscrub (Brown, 1994). This open forest community includes trees ranging from 5 to 10 m high, composed of blue Mexican oak (Quercus oblongifolia), shrub live oak (Q. turbinella), one-seed juniper (Juniperus monosperma), desert acacia (Acacia farneciana), and thorn acacia (A. constricta), with an understory of beargrass (Nolina microcarpa), Parryi agave (Agave parryi), and sotol (Dasiliryon wheeleri). The climate is subtemperate-humid (Garcı́a, 1988). The observation from 2002 suggests that bighorn sheep can disperse farther than the previously reported maximum of 48 km (Shackleton, 1985). We have no documentation of the movement of ewes or the establishment of new populations in the Sonoran–Chihuahuan region. However, because of the proximity of these 3 observations to established populations in New Mexico and Arizona, it is feasible that these individuals came from the Big Hatchet and Peloncillo mountains, respectively (Fig. 1), during their summer movements. Both Los Ojos and Las Palmas ranches contain large areas of continuous habitat with the topographical and biological features required by this species; thus, these areas should be considered for future reintroductions. Reduction of populations in the Big Hatchet and the Peloncillos makes them highly prone to extinction by predation through the Allee effect (Mooring et al., 2004). Reintroductions of bighorn sheep in the mountains of northwestern Chihuahua or northeastern Sonora would increase the opportunities for dispersing individuals to find mates, thereby increasing the long-term viability of the species in the region, assuming that reintroductions would be accompanied by education of local residents to prevent hunting until new, stable populations are established. The case of bighorn sheep in the Sonora– Chihuahua and Arizona–New Mexico international border is just one of many examples of 433 species, including the ocelot (Leopardus pardalis), jaguar (Panthera onca), pronghorn antelope (Antilocapra americana sonorensis), white-sided jack rabbit (Lepus callotis), black-tailed prairie dog (Cynomys ludovicianus), and thick-billed parrot (Rhynchopsitta pachyrhyncha), considered at risk of extinction in one or both countries and requiring immigration of individuals across the border to maintain viable populations (Ceballos and Navarro, 1991; Ceballos et al., 1998, 2005; List et al., 1999). There is an urgent need to address this important conservation issue in both countries to ensure the long-term survival of these taxa. We thank the J. M. Kaplan Fund, the DGAPA (National Autonomous University of Mexico), and the Turner Foundation for supporting our research in northern Mexico. M. S. Mooring provided useful comments that greatly improved the manuscript. V. and J. Austin allowed us to work at their property. LITERATURE CITED BROWN, D. 1994. Biotic communities in the southwestern U.S. and northwestern Mexico. Utah University Press, Salt Lake City. CEBALLOS, G., R. LIST, J. PACHECO, P. MANZANO, G. SANTOS, AND M. ROYO. 2005. Prairie dogs, cattle and crops: diversity and conservation of the grassland-shrubland habitat mosaic in northwestern Chihuahua. In: J.-L. E. Cartron, G. Ceballos, and R. S. Felger, editors. Biodiversity, ecosystems, and conservation in northern Mexico. Oxford University Press, Oxford, United Kingdom. Pages 424–438. CEBALLOS, G., AND D. NAVARRO. 1991. Diversity and conservation of Mexican mammals. In: M. A. Mares and D. J. Schmdly, editors. Latin American mammalogy: history, biodiversity, and conservation. University of Oklahoma Press, Norman. Pages 167–198. CEBALLOS, G., P. RODRÍGUEZ, AND R. MEDELLIN. 1998. Assessing conservation priorities in megadiverse Mexico: mammalian diversity, endemicity, and endangerment. Ecological Applications 8:8–17. GARCÍA, E. 1988. Modificaciones al sistema de clasificación climática de Köepen. Instituto de Geografı́a, Universidad Nacional Autónoma de México, Mexico, D.F. GUERRERO, C. I., I. TOVAR, AND S. ALVAREZ. 2003. Factores que afectan la distribución espacial del borrego cimarrón Ovis canadensis en la Sierra del Mechudo, B.C.S., México. Anales del Instituto de Biologı́a, Universidad Nacional Autónoma de México 74(1):83–98. 434 The Southwestern Naturalist HALL, R. 1981. The mammals of North America. John Wiley and Sons, New York. HAYES, C. L., E. S. RUBIN, M. C. JORGENSEN, R. A. BOTTA, AND W. M. BOYCE. 2000. Mountain lion predation of bighorn sheep in the peninsular ranges of California. Journal of Wildlife Management 64:954:959. HOFFMEISTER, D. F. 1986. Mammals of Arizona. University of Arizona Press, Tucson. KRAUSMAN, P. R., A. V. SANDOVAL, AND R. C. ETCHBERGER. 1999. Natural history of desert bighorn sheep. In: R. Valdez and P. Krausman, editors. Mountain sheep of North America. University of Arizona Press, Tucson. Pages 139–191. LEE, R. 1999. Arizona. In: D. E. Toweill and V. Geist, editors. Return to royality. Boone and Crockett Club and Foundation for North American Wild Sheep, Missoula, Montana. Pages 160–163. LEOPOLD, A. S. 1959. Wildlife of Mexico: the game birds and mammals. University of California Press, Berkeley. LIST, R., G. CEBALLOS, AND J. PACHECO. 1999. Distribution and conservation status of the North American porcupine (Erethizon dorsatum) in Mexico. Southwestern Naturalist 44:400–404. MEDELLIN, R., F. COLCHERO, C. MANTEROLA, F. RAMIREZ, AND G. CEBALLOS. 1999. The Tiburón island bighorn sheep program: an example of binational, interinstitutional cooperation and sustainable development in a Mexican Indian and protected area. Wild Sheep, Spring:71–72. MEDELLÍN, R., C. MANTEROLA, M. VALDÉZ, D. G. HEWITT, D. DOAN-CRIDER, AND T. E. FULBRIGHT. 2005. History, ecology, and conservation of the prong- vol. 51, no. 3 horn antelope, bighorn sheep, and black bear in Mexico. In: J.-L. E. Cartron, G. Ceballos, and R. S. Felger, editors. Biodiversity, ecosystems, and conservation in northern Mexico. Oxford University Press, Oxford, United Kingdom. Pages 387–404. MOORING, M. S., T. A. FITZPATRICK, T. T. NISHIHIRA, AND D. D. REISIG. 2004. Vigilance, predation risk, and the Allee effect in desert bighorn sheep. Journal of Wildlife Management 68:519–532. NEW MEXICO DEPARTMENT OF GAME AND FISH. 2002. Desert bighorn sheep. Wildlife Notes, New Mexico Department of Game and Fish, Santa Fe. RUBIN, E. S., W. M. BOYCE, M. C. JORGENSEN, S. G. TORRES, C. L. HAYES, C. S. O’BRIEN, AND D. A. JESSUP. 1998. Distribution and abundance of bighorn sheep in the peninsular ranges, California. Wildlife Society Bulletin 16:539–551. SECRETARÍA DEL MEDIO AMBIENTE Y RECURSOS NATURALES. 2002. Norma Oficial Mexicana NOM-059ECOL-2001. Protección ambiental-Especies nativas de México de flora y fauna silvestres-Categorı́as de riesgo y especificaciones para su inclusión, exclusión o cambio-Lista de especies en riesgo. México City, D.F. SHACKLETON, D. M. 1985. Ovis canadensis. Mammalian Species 230:1–9. SMITH, N., AND P. R. KRAUSMAN. 1988. Desert bighorn sheep: a guide to selected management practices. U.S. Fish and Wildlife Service Biological Report 88(35), Washington, D.C. Submitted 4 January 2005. Accepted 19 January 2006. Associate editor was Cheri A. Jones. MAXILLARY CANINES IN BIGHORN SHEEP BRIAN D. JANSEN* AND PAUL R. KRAUSMAN School of Natural Resources, University of Arizona, Tucson, AZ 85721 *Correspondent: [email protected] ABSTRACT Bighorn sheep (Ovis canadensis) occasionally have small, procumbent maxillary canines that do not penetrate the gums. However, the frequency of these vestigial teeth is only 3%. We collected 25 skulls from an isolated and indigenous population of bighorn sheep in the Silver Bell Mountains, Arizona. We compared the frequency of maxillary canines with data reported in scientific literature and in the mammalogy collection at the University of Arizona, and found a significantly higher frequency of maxillary canines in bighorn sheep skulls from the Silver Bell Mountains than in skulls collected throughout the southwestern United States. We separated skulls by sex and age and found that male and female skulls (⬎6 months of age at death) from the Silver Bell Mountains both had a significantly higher frequency of maxillary canines than did skulls from the Southwest. Lamb skulls (⬍6 months of age at death) exhibited a higher frequency of maxillary canines than did lamb skulls from throughout the Southwest; however, our small September 2006 Notes 435 sample size (Silver Bell, n ⫽ 5; Southwest, n ⫽ 12) was statistically inconclusive. The trait for maxillary canines might be maintained or inflated because of genetic isolation from other bighorn sheep populations. RESUMEN Los borregos cimarrones (Ovis canadensis) tienen ocasionalmente pequeños colmillos maxilares acostados que no penetran las encı́as. Sin embargo, la frecuencia de estos dientes vestigiales es solamente del 3%. Recogimos 25 cráneos de borregos cimarrones de una población aislada y nativa en las montañas Silver Bell, Arizona. Comparamos la frecuencia de los colmillos maxilares con los datos obtenidos de la literatura cientı́fica y en la colección de mamı́feros de la Universidad de Arizona, y encontramos una frecuencia significativamente más alta de colmillos maxilares en los cráneos de O. canadensis de las montañas Silver Bell que en los recogidos a través del suroeste de los Estados Unidos. Separamos los cráneos por sexo y edad y encontramos que tanto los cráneos de machos como los de las hembras (⬎6 meses de edad a la muerte) de las montañas Silver Bell tenı́an una frecuencia más alta de los colmillos maxilares que los cráneos del suroeste de USA. Los cráneos de los cabritos (⬍6 meses de edad a la muerte) exhibieron una frecuencia más alta de los colmillos maxilares que los cráneos a través del suroeste de USA; sin embargo, nuestro pequeño tamaño de muestra (Silver Bell, n ⫽ 5; suroeste, n ⫽ 12) fue estadı́sticamente inconcluso. La caracterı́stica de tener colmillos maxilares se puede mantener o aumentar debido al aislamiento genético de otras poblaciones de borregos cimarrones. Maxillary canine teeth occur uncommonly among species of Bovidae (Benson, 1943). When they occur, these canines are small and procumbent, rarely penetrating the gum line (Benson, 1943; Allred and Bradley, 1965). Skulls of bighorn sheep rarely have maxillary canines (Benson, 1943). Two of 53 bighorn sheep skulls (4%) and 6 of 37 bighorn sheep skulls (16%) from Washington had maxillary canines (Benson, 1943; Dalquest and Hoffmeister, 1948). One male of 132 skulls (74 males, 48 females) from the Desert Game Range, Nevada, bore maxillary canines (Allred and Bradley, 1965). During a radiotelemetry study of bighorn sheep in the Silver Bell and Waterman mountains (32⬚24.5⬘N, 111⬚29.5⬘W), Arizona, from 2003 to 2005, we collected skulls of bighorn sheep found during our regular fieldwork. We noticed that the frequency of skulls with maxillary canines seemed higher than previously reported. For 25 skulls collected with intact distal rostra, we recorded the presence or absence of maxillary canines or alveoli. We subsequently used data reported by Welles and Welles (1961), Allred and Bradley (1965), and Bradley and Allred (1966) to calculate frequencies of maxillary canines in bighorn sheep from the southwestern United States. We excluded data reported by Benson (1943), because localities were not included for all 53 skulls, and by Deming (1952), because those data likely were duplicated by Allred and Bradley (1965) and the reported frequencies were similar to those in other literature. We supplemented published data by examining skulls in the University of Arizona mammalogy collection representing O. canadensis that did not come from the Desert Game Range and were collected after 1966 (the most recent publication date on this topic). No specimens from the Silver Bell Mountains were reported in other publications, and we excluded all data from the Silver Bell Mountains from calculations regarding the general population of bighorn in the Southwest. We used a Fisher’s Exact Test to determine whether maxillary canines were present in a higher frequency of all, male, female, or lamb skulls from the Silver Bell Mountains than those of the general population. We collected 25 skulls of bighorn sheep (4 male; 16 female; 5 lambs ⬍6 months old) with intact distal rostra. Of these 25 skulls, 9 (2 male; 3 female; 4 lambs) had maxillary teeth; that is, 36% (50% of the males; 19% of the females; 80% of the lambs) of our sample from the Silver Bell Mountains had maxillary canines. We compared our 25 skulls with 477 skulls from throughout the Southwest: 1 from Death Valley, California (Welles and Welles, 1961); 122 from Desert Game Range (Allred and Bradley, 1965); 316 skulls from Arizona, from Joshua Tree National Monument and Death Valley, California, and from the Desert Game Range (Bradley and Allred, 1966); and 38 skulls from the University of Arizona from throughout Arizona. Of the 477 skulls, 14 had 436 vol. 51, no. 3 The Southwestern Naturalist maxillary canines, representing 3% of the sample from the Southwest. Of the 465 adult skulls (291 male; 174 female), we found 9 males (3%) and 1 female (⬍1%) with maxillary canines. Four of the 12 lamb skulls (33%) had maxillary canines. Skulls of bighorn sheep from the Silver Bell Mountains had a higher frequency of maxillary canines than those of bighorn sheep from throughout the Southwest (2-tailed P ⬍ 0.0001). Comparisons between sex and age revealed that adult males and females had a higher incidence of maxillary canines (male, 2-tailed P ⫽ 0.007; female, 2-tailed P ⫽ 0.002) than did males and females from throughout the Southwest. Lambs (80%) also had a higher incidence of maxillary canines than those from elsewhere (33%); however, due to small sample size, our comparison was statistically inconclusive (2-tailed P ⫽ 0.131). Bovids have lacked upper incisors and canines since the Oligocene (Benson, 1943). Maxillary canine teeth seem to have no function (Benson, 1943). It does not seem that they arise from a developmental anomaly, because they occur in both neonates and adults. Because they do not penetrate the gums, these teeth probably do not confer any advantages. Reasons for these teeth, other than genetic anomalies, are unknown. Bighorn sheep populations in the Southwest exist in naturally fragmented mountain ranges, often far from neighboring populations (Bleich et al., 1990). Furthermore, human development has added additional barriers that might inhibit sheep movement into and away from the Silver Bell Mountains through local reduction or extinction of neighboring populations, interstate highways, aqueducts, fencing, and urban development. We suggest the frequency of maxillary canines in the bighorn sheep from the Silver Bell Mountains has been inflated because of genetic isolation from other populations. LITERATURE CITED ALLRED, L. G., AND W. G. BRADLEY. 1965. Necrosis and anomalies of the skull in desert bighorn sheep. Desert Bighorn Council Transactions 9: 75–81. BENSON, S. B. 1943. Occurrence of upper canines in mountain sheep, Ovis canadensis. American Midland Naturalist 30:786–789. BLEICH, V. C., J. D. WEHAUSEN, AND S. A. HOLL. 1990. Desert-dwelling mountain sheep: conservation implications of a naturally fragmented distribution. Conservation Biology 4:383–390. BRADLEY, W. G., AND L. G. ALLRED. 1966. A comparative study of dental anomalies in desert bighorn sheep. Desert Bighorn Council Transactions 10: 78–85. DALQUEST, W. W., AND D. F. HOFFMEISTER. 1948. Mountain sheep from the state of Washington in the collection of the University of Kansas. Transactions of the Kansas Academy of Science 51: 224–234. DEMING, O. V. 1952. Tooth development of the Nelson bighorn sheep. California Fish and Game 38: 523–529. WELLES, R. E., AND F. B. WELLES. 1961. The bighorn of Death Valley. U.S. Department of the Interior, National Park Service, Fauna Series 6, Washington, D.C. Submitted 27 August 2005. Accepted 19 January 2006. Associate Editor was Cheri A. Jones. DISTANCES MOVED BY STARTLED DESERT MULE DEER PAUL R. KRAUSMAN,* JOSH AVEY, COLEEN F. BROWN, PATRICK K. DEVERS, JOHN C. TULL, BRIAN D. JANSEN, AND JAMES W. CAIN, III 325 Biological Sciences East, School of Natural Resources, University of Arizona, Tucson, AZ 85721 (PRK, CFB, BDJ, JWC) Arizona Game and Fish Department, 2222 West Greenway Road, Phoenix, AZ 85023 (JA) Department of Fish and Wildlife Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0321 (PKD) M S-314 Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV 89557 (JCT) *Correspondent: [email protected] September 2006 Notes 437 ABSTRACT The behavior of startled desert mule deer (Odocoileus hemionus eremicus) has been described, but distances moved after being startled have not been reported. We located 8 radiocollared deer (6 females, 2 males) for 8 mo, intentionally approaching them afoot until we startled them, waited 15 min, and relocated them (ⱕ90 min). The deer were startled and relocated 56 times. Mean time elapsed between startling and relocation was 34.5 min (SE ⫽ 3.9 min). Mean distance moved was 893.2 m. When researchers disturb mule deer before obtaining data describing movement or habitat use, they should abandon their attempts for 24 h to avoid bias in those data. RESUMEN El comportamiento de los venados buros del desierto (Odocoileus hemionus eremicus) cuando se asustan ha sido descrito, pero la distancia que se desplazan después de ser asustados no ha sido registrada Monitoreamos 8 venados (6 hembras, 2 machos) con radio-collares por 8 meses, acercándonos intencionalmente a pie hasta que los asustamos, esperamos 15 min y los volvimos a localizar (⬍90 min). Los venados fueron asustados y localizados nuevamente 56 veces. El tiempo medio que transcurrió entre asustar al animal y la relocalización fue de 34.5 min (ES ⫽ 3.9 min). La distancia media que los animales se trasladaron fue de 893.2 m. Cuando los investigadores molestan a los venados, antes de obtener datos sobre los desplazamientos o el uso del hábitat, deben dejarlos por 24 h para evitar sesgo en los datos. Radiotelemetry has become a standard tool in research regarding movements and habitat use of ungulates. For example, radiotelemetry has allowed the study of large-scale movements by desert mule deer (Odocoileus hemionus eremicus) during the day (Leopold and Krausman, 1987) and night (Hayes and Krausman, 1993). However, researchers using radiotelemetry and other research techniques can startle deer and other ungulates, thus affecting their movements. Disturbance by aircraft has been documented (Krausman and Hervert, 1983; Krausman et al., 1986; Bleich et al., 1990), but little is known about the immediate movements of deer after they are startled by researchers on foot using radiotelemetry. Most of the information describing behavior of startled deer in the United States has resulted from general studies of alarm behavior. Mule deer usually run when startled, using a stotting or bounding gait (Geist, 1981). If only moderately startled, the deer will trot away and stop frequently to look back at their pursuers (Spencer, 1969; Geist, 1981). If ungulates move long distances (e.g., long enough to change vegetation associations) when disturbed in the process of researchers locating them with radiotelemetry, data regarding the disturbed animals might be of little value. For example, if an animal is startled and enters a different vegetation association before it is ‘‘located,’’ conclusions related to habitat use could be erroneous. The estimated size of home ranges also could be altered if, when startled, animals are forced into areas not usually used. For example, in Switzerland, when chamois (Rupicapra rupicapra) were approached by joggers, hikers, and mountain bikers, chamois left the area (mean distance moved ⫽ 200 m) (Ingold et al., 1996). Kucera (1976) examined flushing distance of white-tailed deer (O. virginianus) and reported that 389 of 1,034 deer he observed were not sufficiently frightened to run. In 645 cases deer ran, but Kucera (1976) could not determine whether deer were aware of his presence or if any were aware but tolerated him. He concluded, however, that deer were startled more often when he was on foot than when he was in a vehicle or on horseback. Our objective was to determine how far desert mule deer move when startled by researchers tracking them with radiotelemetry on the ground. Our study was conducted in the Tucson Mountains, Pima County, Arizona, west of Tucson, Arizona, during 3 seasons in 1998: winter ( January–March), spring (April–June), and summer ( July–September). Elevations ranged from 689 to 824 m. The area is in the Arizona Upland Subdivision of the Sonoran Desert (Brown, 1982; Rondeau et al., 1996). The area has long hot summers, short mild winters, biseasonal rainfall peaks (i.e., winter and late summer), low relative humidity, and high rates of evaporation. Mean temperatures were 16⬚C and 30⬚C in winter and summer, respectively. Average annual precipitation was 27.9 cm. We tracked 8 radiocollared desert mule deer (6F, 2M) as part of a 2-y study in which we examined movements (Tull and Krausman, 2001). Upon completion of that project, we be- 438 vol. 51, no. 3 The Southwestern Naturalist gan this experiment on 23 January 1998, completing it on 31 August 1998. We located deer with a telemetry receiver (model TR-2, Telonics, Mesa, Arizona) and hand-held Yagi antenna, then plotted their positions with a geographic positioning system (GPS; Magellan Systems Corp., San Dimas, California). After deer were located, we approached them, as if we were obtaining a radiolocation by homing (White and Garrett, 1990), until they left the area. We waited 15 min and relocated them within 90 min. If we were able to relocate the deer, we recorded their position using the GPS and the time elapsed since we startled them. We measured the linear distance from the first location to the second (to the nearest meter) as the distance moved due to startling. We did not intentionally startle them a second time, and deer that continued to move away from us after we began our second location effort were not included in the analysis. We used one-way analysis of variance (ANOVA) to determine whether deer moved significantly farther after being startled in any season. We startled and relocated each deer ⱕ6 times (from dawn to 1200 h) during each season: 16, 22, and 18 times in winter, spring, and summer, respectively. The mean time elapsed between startling and relocation was 34.5 min (SE ⫽ 3.9; range ⫽ 24 to 46 min). There was no difference in distances moved among seasons (F2, 53 ⫽ 0.509, P ⫽ 0.64). Overall, the mean distance moved from the startling point to relocation was 893.2 m (SE ⫽ 134.3, range ⫽ 522 to 1,718 m). During our previous project, the 8 individuals tracked during this study had been radiolocated ⱖ1 time/week from November 1995 to December 1997 (Tull and Krausman, 2001). Thus, deer likely were aware of the presence of researchers even though we never intentionally disturbed them. However, when we intentionally startled them (i.e., by approaching within 25 to 50 m) they moved an average of 893 m in 30 min (i.e., the mean time for a relocation). When desert mule deer were disturbed by a small fixed-wing aircraft flying an average of 80 m above ground level, 7 males moved an average of 430 m and 2 females moved 1,000 and 1,710 m (Krausman et al., 1986). When startled, whether by aircraft or by humans afoot, desert mule deer are displaced. None of the deer that were alerted moved outside of their home ranges (Tull and Krausman, 2001). Also, because the habitat that we were working in was relatively homogeneous, we did not document shifts in habitat use after the deer were startled. However, if other deer respond in a similar manner in heterogeneous habitats, it is likely that disturbances could shift use of habitats. This obviously would bias results if deer-habitat relationships were being examined. Because deer moved ⱖ2 km due to disturbance, we recommend that locations of deer be abandoned for ⱖ24 h if deer are disturbed and move, and the researcher has to pursue the animal. Biologists might not always know whether they have caused disturbance, but if disturbance is suspected, they should pursue different deer. This study was conducted with the approval of the Institutional Animal Care and Use Committee, University of Arizona. The study was funded by the Arizona Agricultural Experiment Station, University of Arizona, Tucson. LITERATURE CITED BLEICH, V. C., R. T. BOWYER, A. M. PAULI, R. L. VERNOY, AND R. W. ANTHES. 1990. Responses of mountain sheep to helicopter surveys. California Fish and Game 76:197–204. BROWN, D. E. 1982. Biotic communities of the American Southwest: United States and Mexico. Desert Plants 4:1–342. GEIST, V. 1981. Behavior: adaptive strategies in mule deer. In: O. C. Wallmo, editor. Mule and blacktailed deer of North America. University of Nebraska Press, Lincoln. Pages 157–223. HAYES, C. L., AND P. R. KRAUSMAN. 1993. Nocturnal activity of female desert mule deer. Journal of Wildlife Management 57:897–904. INGOLD, P., R. SCHNIDRIG-PETRIG, H. MARBACHER, U. PFISTER, AND R. ZELLER. 1996. Tourism/sports de loiser et faune sauvage dans la region alpine Suisse. Office federal de l’environnement, des forets et du paysage (OFEFP). Cahier de l’environnement. Number 262. KRAUSMAN, P. R., AND J. J. HERVERT. 1983. Mountain sheep responses to aerial surveys. Wildlife Society Bulletin 11:372–375. KRAUSMAN, P. R., B. D. LEOPOLD, AND D. L. SCARBROUGH. 1986. Desert mule deer response to aircraft. Wildlife Society Bulletin 14:68–70. KUCERA, E. 1976. Deer flushing distance as related to observers mode of travel. Wildlife Society Bulletin 4:128–129. September 2006 Notes LEOPOLD, B. D., AND P. R. KRAUSMAN. 1987. Diurnal activity of desert mule deer in relation to temperature. Texas Journal of Science 39:49–53. RONDEAU, R. J., T. R. VAN DEVENDER, C. D. BERTLESEN, P. D. JENKINS, R. K. WILSON, AND M. A. DIMMITT. 1996. Annotated flora and vegetation of the Tucson Mountains, Pima County, Arizona. Desert Plants 12:1–284. SPENCER, J. W. 1969. Hunting mule deer. In: W. P. Taylor, editor. The deer of North America: the white-tailed, mule, and black-tailed deer, genus 439 Odocoileus. Their history and management. Wildlife Management Institute, Washington, D.C. Pages 483–522. TULL, J. C., AND P. R. KRAUSMAN. 2001. Use of a wildlife corridor by desert mule deer. Southwestern Naturalist 46:81–86. WHITE, G. C., AND R. A. GARRET. 1990. Analysis of wildlife radio-tracking data. Academic Press, San Diego, California. Submitted 27 August 2005. Accepted 18 November 2005. Associate Editor was Cheri A. Jones.