The Dusky Great Horned Owl (Bubo virginianus saturatus) of the Pacific Northwest region of North America is generally considered to be nonmigratory. Here we report a specimen of a Dusky Great Horned Owl that was salvaged in New Mexico and identified based on comparison of its plumage with a large series of museum skins. We attempted to corroborate this identification by comparing mitochondrial DNA sequences between the specimen and a representative sample of 5 Great Horned Owl subspecies from western North America. This analysis revealed minimal mitochondrial genetic variation and no evidence of population genetic structure, suggesting that the marked plumage differences among subspecies evolved since the late Pleistocene. To evaluate the possibility that the salvaged specimen was transported after death, we analyzed its stomach contents. The stomach contained remains of a desert cottontail (Sylvilagus audubonii), a locally abundant rabbit species in central New Mexico. The mitochondrial haplotype of the rabbit was novel but closely related to haplotypes found in New Mexico and west Texas. This is the first report of long distance movement in the Pacific Northwest subspecies of Great Horned Owl, though we cannot rule out the possibility of anomalous melanism. Although there is tremendous potential for forensic-style phylogeographic investigation of animal movements, this study illustrates that sequence databases are not yet adequate to the task, even for common North American vertebrate species.

Subalpine meadows are some of the most ecologically important components of mountain landscapes, and primary productivity is important to the maintenance of meadow functions. Understanding how changes in primary productivity are associated with variability in moisture and temperature will become increasingly important with current and anticipated changes in climate. Our objective was to describe patterns and variability in aboveground live vascular plant biomass in relation to climatic factors. We harvested aboveground biomass at peak growth from four 64-m² plots each in xeric, mesic, and hydric meadows annually from 1994 to 2000. Data from nearby weather stations provided independent variables of spring snow water content, snow-free date, and thawing degree days for a cumulative index of available energy. We assembled these climatic variables into a set of mixed effects analysis of covariance models to evaluate their relationships with annual aboveground net primary productivity (ANPP), and we used an information theoretic approach to compare the quality of fit among candidate models. ANPP in the xeric meadow was negatively related to snow water content and thawing degree days and in the mesic meadow was negatively related to snow water content. Relationships between ANPP and these 2 covariates in the hydric meadow were not significant. Increasing snow water content may limit ANPP in these meadows if anaerobic conditions delay microbial activity and nutrient availability. Increased thawing degree days may limit ANPP in xeric meadows by prematurely depleting soil moisture. Large within-year variation of ANPP in the hydric meadow limited sensitivity to the climatic variables. These relationships suggest that, under projected warmer and drier conditions, ANPP will increase in mesic meadows but remain unchanged in xeric meadows because declines associated with increased temperatures would offset the increases from decreased snow water content.

Research indicates that low nest success and juvenile survival may be factors contributing to Greater Sage-Grouse population declines. Recent technological advances in microtransmitters have allowed researchers to monitor individual chicks and broods. We initiated a chick survival study in 2006 and used microtransmitters to (1) examine the viability of using microtransmitters on chicks to assess survival, including the effect of handling time during the suturing process; (2) estimate overall chick survival; and (3) compare chick survival in the Strawberry Valley population to other published reports. We used a known-fate model in program MARK to estimate ĉ (overdispersion), weekly survival rates, and 49-day survival of radio-marked chicks. Chick survival rates were lowest during the initial 3 weeks of life, after which point weekly survival stabilized. Survival over 49 days was estimated at 0.25 (SE 0.10) and was comparable to estimates from other populations. Handling time was negatively associated with chick survival, and chicks were 2 times more likely to survive to 49 days when handled for only 5 minutes instead of 19 minutes. We recommend that researchers be judicious in using microtransmitters and make every effort to reduce handling time during transmitter attachment.

Interactions among seeds, mediated by granivorous rodents, are likely to play a strong role in shrubsteppe ecosystem restoration. Past studies typically consider only pairwise interactions between preferred and less preferred seed species, whereas rangeland seedings are likely to contain more than 2 seed species, potentially leading to complex interactions. We examined how the relative proportion of seeds in a 3-species polyculture changes rodent seed selectivity (i.e., removal) and indirect interactions among seeds. We presented 2 rodent species, Peromyscus maniculatus (deer mice) and Perognathus parvus (pocket mice), in arenas with 3-species seed mixtures that varied in the proportion of a highly preferred, moderately preferred, and least preferred seed species, based on preferences determined in this study. We then conducted a field experiment in a pocket mouse—dominated ecosystem with the same 3-species seed mixtures in both “treated” (reduced shrub and increased forb cover) and “untreated” shrubsteppe. In the arena experiment, we found that rodents removed more of the highly preferred seed when the proportions of all 3 seeds were equal. Moderately preferred seeds experienced increased removal when the least preferred seed was in highest proportion. Removal of the least preferred seed increased when the highly preferred seed was in highest proportion. In the field experiment, results were similar to those from the arena experiment and did not differ between treated and untreated shrubsteppe areas. Though our results suggest that 3-species mixtures induce complex interactions among seeds, managers applying these results to restoration efforts should carefully consider the rodent community present and the potential fate of removed seeds.

Understanding anthropogenic and environmental factors that influence seasonal habitat selection is critical in establishing conservation objectives for wildlife populations. However, many resource selection studies provide inferences only for single seasons, potentially masking factors essential to populations during other times of the year. Our objective was to model elk (Cervus elaphus) habitat selection for 4 seasons to identify factors influencing selection within and across seasons. Using aerial relocation data, we evaluated seasonal habitat selection for 46 radio-marked, migratory adult female elk in a 6123-km² landscape in north central Utah, USA, from 1993 to 1997. We evaluated habitat use and availability within estimated seasonal range boundaries by using binary logistic regression to model habitat selection. Habitat use was measured as a response to predictor variables collected from analysis regions around elk locations. Habitat use was compared to habitat availability by measuring those same variables collected from randomly located analysis regions. Our results showed that roads, topography, and vegetation cover influenced elk habitat selection within and across seasons. Roads did not influence elk habitat selection in spring; rather, elk selected areas with aspen (Populus tremuloides) at higher elevations. In summer, elk selected forage-rich habitats, particularly aspen and mountain brush at higher elevations and on cooler aspects. In fall, elk selected sites with steeper slopes at higher elevations in areas with greater cover of aspen and mountain brush than was available in seasonal range boundaries. In winter, elk selected sagebrush (Artemisia spp.)-meadow cover on steeper slopes at lower elevations away from major roads. The full array of seasonal habitat selection patterns we found provides managers with greater options for setting conservation objectives for elk on a year-round basis.

We describe 46 new site records documenting occupancy by American pika (lOchotona princeps) at 21 locations from 8 mountain regions in the western Great Basin, California, and Nevada. These locations comprise a sub- set of sites selected from regional surveys to represent marginal, isolated, or otherwise atypical pika locations, and to provide information for assessing environmental tolerance limits. Several locations are known from historic observations (Madeline Plain, Bodie Mtns., Wassuk Mtns., Mono Craters) and are included here to update current status. Site eleva- tions range from 1848 m to 3392 m; relative to the broad range of pika sites in the region, the new locations have cli- mates that are 2—4 °C warmer and receive approximately half the annual precipitation. Sites are located in lava flows and domes, inselbergs (isolated, rocky exposures on a small hill), eroding bedrock, rock-glacier till, talus slopes, and anthro- pogenic roadbed armaments and mining ore dumps. Several sites are situated in uncommon vegetation contexts, for example, montane desert scrub communities or locations where vegetation adjacent to taluses is sparse or lacking. Prox- imity to surrounding pika habitats (as a measure of marginality) was evaluated based on relative talus distribution pat- terns for 0.5-km, 2.5-km, and 5.0-km circular areas nested around each site. Seven idealized, schematic spatial patterns were used to assess potential connectivity among sites, ranging from “island” (no other talus within the respective areas) to “even” (many talus patches regularly distributed). Applying this approach to the 21 sites demonstrated a simple method for qualitatively assessing pika habitat relative to dispersal potential and metapopulation viability and also revealed complexities of biogeographic patterns related to marginality.

Seed-feeding beetles of the genera Acanthoscelides, Apion, and occasionally Tychius were commonly found occurring in seeds from wild populations of Astragalus filipes and Dalea ornata across rangelands of the United States Intermountain West, resulting in many new state, county, and host records. These 2 legumes, as well as other perennial herbaceous species, are being commercially farmed to produce seed supplies to rehabilitate sagebrush-steppe and adjoining juniper woodlands following wildfires. Most of the seeds examined in this study hosted one or more seed-feeding beetles; beetles that pupate and overwinter in the seeds pose the risk of being transported to storage warehouses and distributed to new seedings, unless the beetles are first detected and then controlled.

Aplodontia rufa (mountain beaver) is considered the sole remaining extant genus and species of an ancient lineage that once broadly inhabited the Great Basin and is now restricted to the Pacific Northwest and portions of California and Nevada. Aplodontia rufa californica in Nevada is distributed patchily at the edge of mountain beaver distribution. Due to concern over the status of these populations this subspecies is listed in Nevada as sensitive. The Nevada Department of Wildlife is concerned about the status of Aplodontia rufa californica populations scattered across areas of central western Nevada and has worked to gain an understanding of the subspecies' current distribution and numbers. Because there is a lack of a thorough genetic analysis of these populations in Nevada, this study aims to assess the evolutionary relationships and connectivity of populations within Nevada and California. Therefore, we sampled each of the 9 known localities of Aplodontia rufa in Nevada, as well as 4 sites from the type locality region of the central Sierra Nevada Mountains of California for comparison, using mitochondrial DNA for phylogenetic and network analyses. Additionally, we used microsatellite markers to assess connectivity of populations within Nevada and to proximate California populations. We found that Nevada populations share mitochondrial DNA haplotypes with California populations and therefore belong to the same subspecies. Furthermore, we found evidence of gene flow between Nevada and California populations. Within Nevada, we detected population differentiation that suggested fragmented populations with restricted connectivity. The results of this study will allow Nevada wildlife managers to develop targeted management strategies to enhance connectivity between populations where it is lacking, to protect connectivity that exists, and also to conserve habitat required by this species. This study increases our understanding of this unique and ancient rodent species at the edge of its distribution.

Foothills rough fescue (Festuca campestris) grasslands provide important foraging habitat for wildlife and livestock in the northwestern United States and southwestern Canada. Foothills rough fescue is sensitive to grazing during late spring—early summer but is believed to be more tolerant of grazing during winter—early spring. We evaluated vegetation and soil impacts from long-term winter—early spring grazing at 2 intensities (HG = heavy grazing, LG = light grazing). We studied a foothills rough fescue grassland in west central Montana, USA, that had been grazed almost exclusively by Rocky Mountain elk (Cervus elaphus nelsoni) during winter—early spring for 58 years. Foothills rough fescue tolerated LG but not HG, whereas bluebunch wheatgrass (Pseudoroegneria spicata) and Idaho fescue (Festuca idahoensis) did not tolerate either LG or HG. Decreased productivity of foothills rough fescue in HG was accompanied by decreased herbaceous ground cover and increased abundance of the invasive dense clubmoss (Selaginella densa). Soil nutrient status (OM, C, N, C:N ratio) did not differ between HG and LG; however, soil bulk density was 18% greater in HG, and the Ah horizon was 20% thinner in HG. Overall, our results indicate that long-term elk grazing during winter—early spring degraded this terrestrial ecosystem, and we conclude that periodic rest from ungulate grazing during winter—early spring is necessary to sustain foothills rough fescue grasslands.

We assessed the effects of livestock grazing on vegetation and small mammals in semiarid habitat at a site in northeastern Nevada. Habitat within a fenced exclosure that had been protected from grazing for more than 50 years supported more vegetation and had greater plant diversity compared to habitat immediately outside the exclosure. Likewise, species richness and abundance of small mammals were greater in ungrazed areas. Results suggest that grazing regulation in recent decades may account for some of the changes seen in regional plants and small mammals over the past century. The incorporation of long-term exclosures in a comparative framework permits differentiation of the direct effects of grazing on biotic communities and thus provides a reference point for assessing the influence of grazing relative to other factors in the interpretation of historical change.

Wind turbines are being deployed all across the world to meet the growing demand for energy, and in many areas, these turbines are causing the deaths of insectivorous migratory bats. One of the hypothesized causes of bat susceptibility is that bats are attracted to insects on or near the turbines. We examined insect remains in the stomachs and intestines of hoary bats (Lasiurus cinereus) found dead beneath wind turbines in New York and Texas to evaluate the hypothesis that bats die while feeding at turbines. Most of the bats we examined had full stomachs, indicating that they fed in the minutes to hours leading up to their deaths. However, we did not find prey in the mouths or throats of any bats that would indicate the bats died while capturing prey. Hoary bats fed mostly on moths, but we also detected the regular presence of beetles, true bugs, and crickets. Presence of terrestrial insects in stomachs indicates that bats may have gleaned them from the ground or the turbine surfaces, yet aerial capture of winged insect stages cannot be ruled out. Our findings confirm earlier studies that indicate hoary bats feed during migration and eat mostly moths. Future studies on bat behaviors and insect presence at wind turbines could help determine whether feeding at turbines is a major fatality risk for bats.

In a landscape, abiotic features, such as boulders, influence microhabitats and consequently affect patterns of vegetation. We hypothesized that boulders in the foothills of the Wasatch Mountains east of Provo, Utah, affected the growth patterns of netleaf hackberry (Celtis reticulata) by providing shade on their north faces. To test this hypothesis, we set up 3 transects 6 m wide and up to 50 m long. Along these transects, we measured all hackberries taller than 30 cm (n = 249). We recorded whether the hackberries grew within 0.5 m of a boulder that was at least 0.5 m along one dimension. We found that hackberries at our study site were more likely to be associated with boulders (n = 225; 90.4%) than to be growing alone (n = 24; 10.7%) (x² = 162.25, df = 1, P < 0.001). For each hackberry associated with a boulder, we took a direction bearing from the center of the boulder to the place where the hackberry was rooted. We found that hackberries associated with boulders were more likely to grow near the south (n = 92; 40.9%) side than near the north (n = 35; 15.6%), west (n = 55; 24.4%), or east sides (n = 43; 19.1%) (x2 = 33.90, df = 3, P < 0.001). These results suggest that boulders influence patterns of hackberry growth and may actually provide thermal radiation that melts snow in the Wasatch foothills, rather than shade protection as we had originally hypothesized.

Arizona bark scorpions (Centruroides sculpturatus Ewing) are commonly found throughout the Sonoran Desert in southwestern North America, and they are well known for being the most venomous scorpion in the United States. Despite their medical significance, C. sculpturatus remains ecologically understudied, and little is known regarding its natural foraging and feeding behaviors. Here, we present the first documented case of C. sculpturatus feeding on the Sonoran Desert centipede (Scolopendra polymorpha Wood) in the wild.

Fifty-six speckled rattlesnakes, Crotalus mitchellii, from western North America were examined for helminths. One species of Cestoda (tetrathyridia of Mesocestoides sp.) and 5 species of Nematoda (gravid adults of Abbreviata terrapenis, Physaloptera abjecta, Thubunaea cnemidophorus, and Travassoascaris araujoi and larvae of Physocephalus sp.) were found. Travassoascaris araujoi had the highest prevalence and greatest mean intensity of helminths infecting C. mitchellii. Three new host records for C. mitchellii are reported. As has been reported for other North American rattlesnakes, C. mitchellii is parasitized by “generalist” helminths.