Cliff Chipmunk Research Articles

Range extension and new records of two Oxyuroidea Cobbold, 1864 parasitizing Cliff Chipmunk, Neotamias dorsalis (Baird, 1855), in the Área de Protección de Flora y Fauna Cerro del Mohinora, Chihuahua, México

As part of an inventory of the parasitic helminths of rodents, two species of the class Oxyuroidea (Heteroxynema cucullatum Hall, 1916 and Rauschtineria eutamii (Tiner, 1948) Hugot, 1980) were collected from three Cliff Chipmunk specimens (Neotamias dorsalis (Baird, 1955)) in the Área de Protección de Flora y Fauna Cerro del Mohinora, Mexico. These nematodes have been recorded in different species of the genus Neotamias (Illiger, 1811), which can be found in sympatry mainly along the entire west coast of the USA. This is the first record of both species in Mexico.

Foraging Behavior Response of Small Mammals to Different Burn Severities

Wildfires cause profound challenges for animals to overcome due to their reliance on vegetation. This study addresses the impact of three levels of forest burn severity (unburned, low, and high burn severity) on the foraging behavior of small mammals in the Pinaleño Mountains (AZ, USA) using the giving up density (GUD) experiment approach. Overall, burn severity affected the foraging behavior of small mammals that spent less time foraging in high burn severity patches. Vegetation characteristics influenced GUD differently based on the level of burn severity. Higher canopy cover was perceived as areas with a higher predation risk (higher GUD) in unburned and low burn severity patches, while cover provided by logs and shrubs decreased the GUD (increased foraging). This suggests a complicated interaction between horizontal (logs, grass, shrub cover) and vertical vegetation cover in relation to burn severity. Fires affected the foraging behavior of the small mammals but did not impact all species in the same way. Generalists, such as Peromyscus sp. and Tamias dorsalis, seemed to forage across all burn severities, while specialist species, such as tree squirrels, tended to avoid the high burn severity patches. Clarifying the complex impacts of fires on small mammals’ foraging behaviors contributes to our understanding of the intricate interactions, at micro-habitat levels, between vegetation structure and the behavioral responses of animals and it can help managers to plan actions to reduce the negative impacts of wildfires.

Diversification, Introgression, and Rampant Cytonuclear Discordance in Rocky Mountains Chipmunks (Sciuridae: Tamias).

Evidence from natural systems suggests that hybridization between animal species is more common than traditionally thought, but the overall contribution of introgression to standing genetic variation within species remains unclear for most animal systems. Here, we use targeted exon capture to sequence thousands of nuclear loci and complete mitochondrial genomes from closely related chipmunk species in the Tamias quadrivittatus group that are distributed across the Great Basin and the central and southern Rocky Mountains of North America. This recent radiation includes six overlapping, ecologically distinct species (Tamias canipes, Tamias cinereicollis, Tamias dorsalis, T. quadrivittatus, Tamias rufus, and Tamias umbrinus) that show evidence for widespread introgression across species boundaries. Such evidence has historically been derived from a handful of markers, typically focused on mitochondrial loci, to describe patterns of introgression; consequently, the extent of introgression of nuclear genes is less well characterized. We conducted a series of phylogenomic and species-tree analyses to resolve the phylogeny of six species in this group. In addition, we performed several population-genomic analyses to characterize nuclear genomes and infer coancestry among individuals. Furthermore, we used emerging quartets-based approaches to simultaneously infer the species tree (SVDquartets) and identify introgression (HyDe). We found that, in spite of rampant introgression of mitochondrial genomes between some species pairs (and sometimes involving up to three species), there appears to be little to no evidence for nuclear introgression. These findings mirror other genomic results where complete mitochondrial capture has occurred between chipmunk species in the absence of appreciable nuclear gene flow. The underlying causes of recurrent massive cytonuclear discordance remain unresolved in this group but mitochondrial DNA appears highly misleading of population histories as a whole. Collectively, it appears that chipmunk species boundaries are largely impermeable to nuclear gene flow and that hybridization, while pervasive with respect to mtDNA, has likely played a relatively minor role in the evolutionary history of this group. [Cytonuclear discordance; hyridization; introgression, phylogenomics; SVDquartets; Tamias.].

Elemental and radionuclide exposures and uptakes by small rodents, invertebrates, and vegetation at active and post-production uranium mines in the Grand Canyon watershed

The effects of breccia pipe uranium mining in the Grand Canyon watershed (Arizona) on ecological and cultural resources are largely unknown. We characterized the exposure of biota to uranium and co-occurring ore body elements during active ore production and at a site where ore production had recently concluded. Our results indicate that biota have taken up uranium and other elements (e.g., arsenic, cadmium, copper, molybdenum, uranium) from exposure to ore and surficial contamination, like blowing dust. Results indicate the potential for prolonged exposure to elements and radionuclides upon conclusion of active ore production. Mean radium-226 in deer mice was up to 4 times greater than uranium-234 and uranium-238 in those same samples; this may indicate a potential for, but does not necessarily imply, radium-226 toxicity. Soil screening benchmarks for uranium and molybdenum and other toxicity thresholds for arsenic, copper, selenium, uranium (e.g., growth effects) were exceeded in vegetation, invertebrates, and rodents (Peromyscus spp., Thomomys bottae, Tamias dorsalis, Dipodomys deserti). However, the prevalence and severity of microscopic lesions in rodent tissues (as direct evidence of biological effects of uptake and exposure) could not be definitively linked to mining. Our data indicate that land managers might consider factors like species, seasonal changes in environmental concentrations, and bioavailability, when determining mine permitting and remediation in the Grand Canyon watershed. Ultimately, our results will be useful for site-specific ecological risk analysis and can support future decisions regarding the mineral extraction withdrawal in the Grand Canyon watershed and elsewhere.

Female-biased sexual size dimorphism: ontogeny, seasonality, and fecundity of the cliff chipmunk (Tamias dorsalis)

Female-biased sexual dimorphism is uncommon in mammals and is usually attributed to increased fecundity of large females. Moreover, sexual dimorphism is usually described for adults, and the ontogeny of sex differences is poorly documented. We studied cliff chipmunks (Tamias dorsalis), a small mammal with female-biased sexual dimorphism, to describe development of sexual dimorphism in juveniles and to measure sexual dimorphism and seasonal body mass in adults. To test the fecundity hypothesis, we compared body mass of females to litter size and body mass of offspring. Juveniles were not sexually dimorphic at emergence from the nest and did not differ in body mass 2 months after emergence. Adult chipmunks maintained a relatively stable body mass in March– October with females consistently larger than males. Maternal mass did not have an effect on litter size or mass of juveniles. Because females were consistently larger than males, the ontogeny of sexual dimorphism may provide insights into selection pressures that lead to female-biased sexual dimorphism.

Communal denning of cliff chipmunks (Tamias dorsalis)

Abstract Rodents are a diverse group that display a range of social systems. Cliff chipmunks (Tamias dorsalis) are documented as solitary across their range; however, we report here observations of communal denning outside of the breeding season in southeastern Arizona. We radiocollared and tracked nursing females and their offspring to locate nocturnal dens from June to October 2013 and 2014. We observed codenning in juvenile siblings, and juveniles and adults. Our social denning observations indicate that cliff chipmunks demonstrate behavioral plasticity.

Occupancy and Habitat Associations of Four Species of Sciurids in Ponderosa Pine-Gambel Oak (Pinus ponderosa-Quercus gambelii) Forests in Northern Arizona

In ponderosa pine-Gambel oak (Pinus ponderosa-Quercus gambelii) forests of north-central Arizona, we examined occupancy and habitats of four species of sciurids (rock squirrel Spermophilus variegatus, golden-mantled ground squirrel S. lateralis, gray-collared chipmunk Tamias cinereicollis, cliff chipmunk T. dorsalis). Numbers of captures were highly variable, suggesting a patchy distribution of species. All four species co-occurred on only one of the study sites. Gray-collared chipmunks and golden-mantled ground squirrels were relatively common on one site only. Golden-mantled ground squirrels were associated with mature forests with high canopy cover and low basal area, whereas gray-collared chipmunks were in locations with large numbers of logs and shallow litter. The two species of chipmunks appeared to be separated in space; gray-collared chipmunks were more common where cliff chipmunks were least common. Rock squirrels were relatively ubiquitous. There was evidence for an association of rock squirrels with increasing rocky cover and decreasing canopy cover, whereas cliff chipmunks occupied rocky areas with high canopy cover and numerous shrubs.

First Record of a Range Extension of the Cliff Chipmunk (Tamias dorsalis) into the Huachuca Mountains

Chipmunks are widely distributed throughout the mountain ranges of Arizona. However, no living chip- munks are known from the Huachuca Mountains despite the availability of favorable habitat. Based upon pelage charac- teristics of captured individuals, we provide the first report of a breeding population of cliff chipmunks (Tamias dorsalis) in the Huachuca Mountains and discuss possible mechanisms of their arrival.

Nest Predators of Ground-nesting Birds in Montane Forest of the Santa Catalina Mountains, Arizona

Abstract We used time-lapse video cameras and track plates to identify nest predators of Red-faced Warblers (Cardellina rubrifrons) and Yellow-eyed Juncos (Junco phaeonotus) in high-elevation (> 2,300 m) forests of the Santa Catalina Mountains in southeastern Arizona. Mammals, especially gray fox (Urocyon cinereoargenteus) and cliff chipmunk (Tamias dorsalis), were the principal nest predators of Red-faced Warblers and Yellow-eyed Juncos within our study system, accounting for 89% of all nest depredations. Our study is one of the first to use video cameras at real nests to document the prevalence of nest predators in montane forest ecosystems. Additional research is needed to learn if mammals are the dominant nest predators in other montane environments.

Habitat selection of rodents along a piñon–juniper woodland–savannah gradient

The biodiversity of pinon-juniper (P-J) woodlands of western North America has received increasing attention from conservationists because of concerns about woodland invasion into adjacent shrub-steppe communities. Small mammals contribute substantially to the faunal diversity of P-J woodlands, but the responses of small mammals to the inherent structural complexity of these woodlands have not been well described. We used occupancy modeling and ordination to describe habitat selection along a woodland-savannah gradient of 4 species of rodents, including 2 putative P-J woodland specialists, Peromyscus truei and Tamias dorsalis .W e accounted for the influences of season and prior conspecific capture on detectability. P. truei and T. dorsalis preferred old-growth woodland sites near rock outcrops with high canopy and bare-ground cover and low herb and shrub cover. Tamias minimus preferred savannah sites with high shrub and grass cover farther from rock outcrops. We found no evidence of resource selection along the gradient by Perognathus parvus. Our results provide insight into the role of habitat selection in facilitating coexistence among closely related species within P-J woodlands and suggest that management efforts that better discriminate between old, presettlement stands and young, invasive stands may enhance regional biodiversity. We demonstrate an effective application of occupancy modeling for describing habitat selection of cryptic rodents, which are particularly prone to imperfect detection. DOI: 10.1644/09-MAMM-A-060.1.

THERE IS NO VALID RECORD OF CLIFF CHIPMUNK (TAMIAS DORSALIS) IN THE SANDIA MOUNTAINS, NEW MEXICO

A report of the cliff chipmunk (Tamias dorsalis) from the Sandia Mountains, New Mexico, was erroneous. The capture location of the specimen was actually the Rio Puerco drainage in Sandoval County. There are no records of the cliff chipmunk from the Sandia Mountains or elsewhere east of the Rio Grande.

Impact of Insect Herbivores on Competition Between Birds and Mammals for Pinyon Pine Seeds

Few studies have considered impacts of insect cone herbivores on bird and mammal seed consumers. Harvests of pinyon pine (Pinus edulis) cones by insects, birds, and mammals were negatively correlated both within and across sites. Birds and mammals significantly increased their cone harvest when the other group was experimentally prevented access to trees, and mammals harvested more cones when insects were removed from trees with an insecticide. These results suggest that stem— and cone—boring insects (primarily Dioryctria albovittella), birds (Clark's Nutcrackers, Pinyon Jays, and Scrub Jays), and mammals (cliff chipmunks and rock squirrels) compete for pinyon pine seeds. Additionally, insects affected the interaction between birds and mammals because the ratio of mammal to bird harvest increased up to 350—fold as insect cone consumption increased. Because insect—infected and uninfested pinyon pines are genetically different, these observations and experiments suggest that genetic interactions between plants and herbivores can affect the structure of a seed—consumer community.

Geographic Variation in Eutamias quadrivittatus with Comments on the Taxonomy of Other Arizonan Chipmunks

Analyses indicate that two subspecies of the chipmunk Eutamias quadrivittatus are recognizable. The widely used name E. q. hopiensis is a syno- nym of E. q. quadrivittatus. A new name is proposed for the other subspecies. The cliff chipmunk in northwestern Arizona is Eutamias dorsalis grinnelli, not E. d. utahensis. The least chipmunk in eastern Arizona is Eutamias minimus operarius, with E. m. arizonensis a synonym of this subspecies. Chipmunks of the species Eutamias quadrivittatus consist of two groups: a large-sized, dark-colored form that usually is found in pine or spruce-fir forests of central and southern Colorado, northern New Mexico, northeastern Arizona, and western Oklahoma; and a small-sized, light-colored form that usually is found in open, juniper- pinyon woodlands among rocks in Utah, north-central Arizona, and western-most Colorado. The differences in size, both externally and cranially, are appreciable and probably are more significant than color, which may be quite variable. The zone of intergradation be- tween these groups is a geographically narrow one in western Colo- rado and northeastern Arizona (see Fig. 1). Analysis of chromosomes of the two groups shows no differences (Sutton and Nadler 1969:528) and according to White (1953b:621-622), the western group has a smaller baculum with a more distinct angle between the tip and shaft. The western group of chipmunks presently is called Eutamias quadrivittatus hopiensis, with the type locality at Keams Canyon, Navajo Co., Arizona. Unfortunately, however, specimens from Keams Canyon do not have the small size characteristic of the western pop- ulations and therefore the name hopiensis cannot be used for the western race. A detailed analysis of specimens from Keams Canyon,

A New Subspecies of the Cliff Chipmunk from Coastal Sonora, Mexico

A new subspecies of Eutamias dorsalis is formally described. This subspecies apparently is confined to coastal Sonora north of Guaymas. Its head and body length is less than that of E. d. dorsalis, and it has a much smaller and narrower skull, a proportionately broader rostrum, and longer ossa genitalia. Loomis and Stephens (1965) were the first to report the presence of the cliff chipmunk in coastal Sonora, although specimens previously had been taken there (W. J. Schaldach, Jr., and A. L. Gardner, pers. comm.). Careful examination of 24 of these chipmunks collected between 1960 and 1973 has led us to reconsider Loomis and Stephens' assignment of the population to E. d. dorsalis. Our original hypothesis was that the coastal Sonoran chipmunks might have some affinity with the desert-dwelling E. merriami meridionalis directly across the Gulf of California (Hall and Kelson 1959). However, subsequent examination of specimens from Baja California revealed that the two populations are not closely related (Dunford and Davis 1975; Callahan 1975). The range of E. d. dorsalis extends from the Grand Canyon in Arizona to northwestern Durango (Hall and Kelson 1959). Specimens from the southern part of this range are more distinctly striped and slightly larger than are those from the north, but these differences are not great enough to warrant subdivision of the taxon. Since the coastal Sonoran chipmunks are small and indistinctly striped, we felt that it would be statistically more meaningful to compare them with the Arizona form of E. d. dorsalis, which they more nearly resemble, rather than with the southern form. Cranial and external measurements of the latter are given by Lidicker (1960) and by Allen (1904). MATERIALS AND METHODS. All specimens we collected were prepared as standard study skins with skulls. Institutions from which specimens were borrowed are identified by the initials UA (University of Arizona, Department of Ecology and Evolutionary Biology); CSLB (California State University, Long Beach,

Cliff Chipmunk Vocalizations and Their Relevance to the Taxonomy of Coastal Sonoran Chipmunks

Cliff Chipmunk Vocalizations and Their Relevance to the Taxonomy of Coastal Sonoran Chipmunks

Annual Cycle of Cliff Chipmunks in the Santa Catalina Mountains, Arizona

Field data on seasonal activity, body weights, molt, and reproduction were collected during a 15-month trap-release study of cliff chipmunks, Eutamias dorsalis, in a pine-oak forest in the Santa Catalina Mountains of southeastern Arizona. Males were active throughout the year with a lull in late December and January, but females disappeared completely from late December through February and did not fully resume activity until late April. Neither sex appeared to gain weight before the period of winter inactivity, and their weights were lowest following this period. Females were consistently heavier than males among both adults and juveniles. Adult females molted to summer pelage mainly during June and July, about one month later than adult males. This delay may reflect the energetic burden of breeding for females, but some females were actively molting while pregnant and lactating. Males were reproductively active from January through June, but the actual breeding season varied between the two summers studied. In 1970 most females copulated in late May and their young did not appear above ground until early August, but in 1971 females started to copulate in April and young chipmunks first appeared in late June. The lateness of the 1970 season may have been due to an unusually cold spring. During both years some females appeared to have copulated well after the majority, which produced an extended breeding season. There were no records of females having more than one litter per year. Although almost all adult females bred during 1970, a large proportion apparently did not breed during 1971, perhaps owing to the severe winter-spring drought of 1970 to 1971. The breeding season of cliff chipmunks in Arizona and New Mexico has a wider seasonal spread than for other species of Eutamias, possibly because of both winter and late summer precipitation and fairly mild, short winters. Food availability seems to be low in southern Arizona during the hot dry season (April to June) and greatest during the late summer rains (July to September), yet cliff chipmunks breed during the hot dry season as do most species of birds and mammals in this area. This observation contrasts with the prediction that vertebrates should attempt to raise offspring when food is most available.

Food preferences of the cliff chipmunk, Eutamias dorsalis, in northern Utah

Food preferences of the cliff chipmunk, Eutamias dorsalis, in northern Utah

The Ectoparasites of Some Mammals from the Chiricahua Mountains, Arizona

an area of about 40 miles long and 20 miles across at their widest part. The areas where trapping was done included grassland, oak woodland, pinyonjuniper, and Douglas fir-yellow pine associations. The desert grassland area is located between the towns of Rodeo and Portal on the east side of the mountains. The oak woodland is located along the lower reaches of Cave Creek between Portal and the American Museum of Natural History's Southwestern Research Station. The pinyon-juniper types are along the road between the research station and Onion Gap and the town of Paradise. The Douglas fir-yellow pine habitat is between Onion Gap and Rustlers Park near the top of the mountain. The mammals taken from the desert grassland were Merriam's kangaroo rat (Dipodomys merriami Mearns), silky pocket mouse (Perognathus flavus Baird), desert pocket mouse (Perognathus penicillatus Woodhouse), Harris' antelope ground squirrel (Citellus harrisii (Audubon and Bachman)), spotted ground squirrel (Citellus spilosoma (Bennett)), white-throated wood rat (Neotoma albigula Hartley), southern grasshopper mouse (Onychomys torridus (Coues)), cactus mouse (Peromyscus eremicus Baird), and deer mouse (P. maniculatus sonoriensis (LeConte)). From the oak woodland, which follows Cave Creek and its tributaries, we captured the brush mouse (Peromyscus boylii (Baird)), silky pocket mouse, a coati (Nasua narica (L.)) and the cliff chipmunk (Eutamias dorsalis (Baird)). From the pinyon-juniper habitat we took the brush mouse, the rock mouse (Peromyscus nasutus (J. A. Allen)), the Mexican wood rat (Neotoma mexicana Baird) and the cliff chipmunk. A white-tailed deer (Odocoileus virginianus Zimmerman) that had been taken from this habitat was also examined. The Mexican wood rat and cliff chipmunk were taken at the upper edge of the pinyon-juniper habitat where there is a close association with the Douglas fir-yellow pine association. From this latter habitat we captured the deer mouse (Peromyscus maniculatus rufinus (Merriam) ), western harvest mouse (Reithrodontomys megalotis (Baird)), rock mouse, brush mouse, Mexican wood rat and the cliff chipmunk. The animals were collected by setting out lines of snap traps through the several habitat types. The traps were placed one to the station, with stations about 30 feet apart. The traps were baited with peanut butter and left out for 3 days. A total