Carrying behavior is exhibited for myriad purposes by a variety of animals, including mammalian carnivores, but it has been poorly studied. We used wildlife camera data to document and describe carrying behavior in a suite of native and domestic mammalian carnivores in Colorado, USA. Our objectives were to estimate the carrying rate for each carnivore species, assess the relationship between carrying rate and carnivore body mass, compare items carried to known diets and with proximity to urbanization, and explore seasonal variation in carrying rate. We documented carrying behavior in red foxes (Vulpes vulpes), coyotes (Canis latrans), bobcats (Lynx rufus), gray foxes (Urocyon cinereoargenteus), pumas (Puma concolor), and domestic cats (Felis catus). These carnivores carried objects at relatively low rates (range 0.44%–3.40%), although smaller-bodied carnivores carried items at greater rates than larger-bodied species. Prey items recorded by remote cameras were consistent with vertebrates known to be consumed by each species, and anthropogenic and synanthropic items were more common near the wildland-urban interface. For red fox, the species with the largest sample of carrying events, the rate of carrying varied by season, with increased rates during spring and summer months. Systematic exploration of carrying behavior has the potential to lend insight into carnivore diet in space and time and into shifts in dietary patterns along the wildland-urban interface. We demonstrate the power of camera trap data to examine these relationships and encourage further research of carrying behavior.

Understanding the processes that underlie forest resilience is of increasing importance as climate change and shifting disturbance regimes continue to impact western forests. Forest research and management efforts within the low-diversity conifer forests of the U.S. Rocky Mountains have typically focused on relatively monotypic stands dominated by a single cohort, but mixed-conifer stands, such as those codominated by Abies lasiocarpa and Pinus contorta have been less widely studied. The presence of A. lasiocarpa may enhance resilience to fire- and mountain pine beetle–induced mortality and depends on successful A. lasiocarpa recruitment under a range of environmental conditions. The purpose of this study was to quantify the effects of key forest structural characteristics and environmental conditions on recruitment of A. lasiocarpa in a midelevation mixed-conifer forest in the central Rocky Mountains. To address this aim, A. lasiocarpa seedling density, light availability, neighborhood basal area, and soil fertility were measured across 24 plots, and the relative effects of each measured variable, temperature, and precipitation on seedling density were quantified within a Bayesian multilevel regression model. Model results showed nonsignificant effects of climate, light availability, and neighborhood index on seedling density; a significant positive association between seedling density and the interaction between soil fertility and neighborhood index; and a strong negative relationship between seedling density and soil fertility. We posit that the negative association with soil fertility in these nutrient-poor forests reflects an underlying gradient in soil moisture availability that corresponds with water flux pathways. Ultimately, much of the variance in seedling densities was explained by latent plot and year effects, indicating that A. lasiocarpa establishment in this mixed-conifer forest is likely governed by a complex suite of environmental factors that vary across fine spatiotemporal scales.

Urban centers are not where one expects to find new species. Yet, we report here a newly recognized ant, Strumigenys ananeotes sp. nov., in an urban yard in Salt Lake City, Salt Lake County, Utah, USA. The genus Strumigenys is a major radiation of litter ants that are found primarily in the wet tropics and subtropics. They are extremely rare in western North America, known only from sites hundreds of kilometers south and west of Salt Lake City. The new species is related to species from southern Arizona and is presumed native. We propose that it is normally restricted to moist, subterranean microhabitats in an otherwise arid region, but that anthropogenic activity has created an urban forest with summer conditions similar to eastern deciduous forest. Strumigenys ananeotes may now have a greatly expanded habitat and visibility, a case of a native species benefiting from human development rather than being displaced.

Vegetation composition (i.e., relative proportion of species) and configuration (i.e., horizontal and vertical arrangement of the plant components) in sagebrush-steppe ecosystems are fundamental determinants of the suitability of nesting habitat for Greater Sage-Grouse (Centrocercus urophasianus). The spatial arrangement of shrub and herbaceous canopy cover conceals Greater Sage-Grouse from predators and protects the nest from natural hazards, and gaps in vegetative cover provide escape routes for hens. Most sage-grouse habitat studies quantify vegetation composition, but few quantify habitat configuration at fine scales. We used ground-based lidar (light detection and ranging) data from Greater Sage-Grouse nesting habitat to test the applicability of a metric calculated from the traditional canopy gap intercept measurements to quantify shrub canopy configuration (shrub patchiness). Vegetation surveys were conducted on 30 randomly selected nest and non-nest sites (15 of each); we acquired high-resolution ground-based lidar data for 12 plots at 3 nest locations. Variation in canopy gap size was used as a metric to represent shrub configuration characteristics. We measured the variability in gap size among shrubs within lidar point cloud data sets using a lacunarity index at multiple scales. We measured variability of gaps from line transects by calculating the variance to mean-square ratio of gap size. Correlations (r) between measures of gap size variation from the 2 techniques ranged from 0.76 to 0.83 (r² = 0.58–0.69). Our results support the use of canopy gap intercept measures to quantify configuration (patchiness) of shrub cover and thus complement vegetative composition metrics. Gap sizes were more variable at nest sites than at non-nest sites, suggesting that gap size variability may be a useful vegetative configuration metric to characterize sage-grouse nesting habitat. The fine-scale habitat metrics we evaluated provide a more refined tool for land managers to characterize local variation in wildlife habitat within shrubland ecosystems and can be derived from the existing gap intercept data.

Riparian corridors in the western United States harbor diverse biological communities that are threatened by reductions in available freshwater, changes to natural disturbance regimes, and anthropogenic disturbances. Limited data are available about bat roosts in riparian habitats in the southwestern United States. We examined day roosts of 3 sympatric Myotis species, the southwestern myotis (Myotis auriculus), Arizona myotis (Myotis occultus), and Yuma myotis (Myotis yumanensis), along the Mimbres River in southwestern New Mexico. We tracked 3 M. auriculus, 3 M. occultus, and 1 M. yumanensis to 16 Fremont's cottonwoods (Populus fremontii), 2 velvet ash (Fraxinus velutina), and 1 Arizona walnut (Juglans major) within the floodplain. Roost trees generally had a greater diameter and greater likelihood of exhibiting fire damage than nearby trees. Moreover, several roosts were in tree species not previously known to be used by these bat species, and bats did not roost in human-made structures in this arid riparian corridor.

Recruitment of Indian ricegrass (Achnatherum hymenoides) seedlings occurs primarily from surface seed caches made by scatter-hoarding desert rodents of the family Heteromyidae. We used radiolabeled Indian ricegrass seeds in field seed-caching experiments with 5 coexisting heteromyid species (Dipodomys deserti, D. merriami, D. microps, Microdipodops pallidus, and Perognathus longimembris) to compare their potential effectiveness as dispersers. Dipodomys microps individuals deposited seeds almost exclusively in larders rather than in scatter hoards, implying that this species is unlikely to be an important seed disperser. Among the other species, individual caches made by larger species had more seeds than those made by smaller species, but smaller species made more caches. At the level of individual animals, M. pallidus was the most effective disperser in a quantitative sense; they made more caches than other species tested and placed fewer excess seeds in caches relative to optimal cache sizes for Indian ricegrass seedling establishment. However, because D. merriami individuals were considerably more abundant at the study site than other species and were also avid scatter hoarders, D. merriami is likely to be the most quantitatively effective disperser of Indian ricegrass seeds at the species level. Ranking species according to qualitative effectiveness (e.g., by considering effects such as the caching microsite on seedling establishment) was more ambiguous. For example, P. longimembris made relatively shallow caches that most closely match optimal planting depths for Indian ricegrass seedling emergence, but such shallow caches are probably more likely than deeper caches to be discovered by foraging rodents before they can germinate. With the possible exception of D. microps, any of the species we tested may be effective dispersers of Indian ricegrass seeds.

Arthropod-bacterial symbioses are prevalent and play significant roles in ecosystems and the economy, and in some cases, habitat invasion. Wolbachia bacteria form symbiotic associations with a wide range of arthropod hosts and can affect both host reproduction and resistance to viral infections. The extent to which Wolbachia infects different arthropod species is fundamental not only to host biology, but also to the health of humans, ecosystems, and agriculture. Much of what we know about the effects of Wolbachia comes from a few key taxa, such as the model organism Drosophila melanogaster and the mosquito vector of human disease, Aedes aegypti. The majority of arthropods, even at higher taxonomic levels, have not been tested for infection, with a lack of surveys conducted in western North America. We screened and characterized Wolbachia diversity in arthropods in 2 types of collections in western North America: broad surveys and targeted collections of species known to be infected with Wolbachia. Our goals were to (1) find new Wolbachia strains and hosts, (2) characterize Wolbachia in commonly studied taxa to see whether there are different infection frequencies or strain types in this location, and (3) compare new Wolbachia strains in western North America to previously characterized strains. PCR screening of broadly sampled arthropods with Wolbachia-specific 16S rDNA (W16S) identified 5 novel host species. Three of these are invasive: a ground beetle, Nebria brevicollis (Coleoptera: Carabidae); a cereal crop agricultural pest, Oulema melanopus (Coleoptera: Chrysomelidae); and a residential nuisance pest, Raglius alboacuminatus (Hemiptera: Rhyparochromidae). The crab spider Philodromus dispar (Araneae: Philodromidae) is nonnative, though not considered invasive, and the hyaline grass bug Liorhyssus hyalinus (Hemiptera: Rhopalidae) is of undetermined origin. To characterize 9 novel Wolbachia strains in our collections, we analyzed the 5-gene MultiLocus Sequence Type (MLST) and the Wolbachia surface protein gene (wsp). We identified 10 novel alleles among 5 MLST genes and 10 novel alleles of the highly variable regions (HVR) of wsp. This is the first report of Wolbachia hosts and strain identification from the Pacific Northwest and Rocky Mountain regions. These studies contribute to our understanding of the natural history of arthropod hosts, the biogeography of Wolbachia, and host-symbiont evolution. Moreover, strain identification is the first step in implementing Wolbachia-based biocontrol for conservation and pest mitigation, including control of the invasive N. brevicollis, O. melanopus, and R. alboacuminatus reported herein.

Since 1993, elk (Cervus canadensis nelsoni) abundance in the Black Hills of South Dakota has been estimated using a detection probability model previously developed in Idaho, though it is likely biased because of a failure to account for visibility biases under local conditions. To correct for this bias, we evaluated the current detection probability across the Black Hills during January and February 2009–2011 using radio-collared elk. We used logistic regression to evaluate topographic features, habitat characteristics, and group characteristics relative to their influence on detection probability of elk. Elk detection probability increased with less vegetation cover (%), increased group size, and more snow cover (%); overall detection probability was 0.60 (95% CI 0.52–0.68), with 91 of 152 elk groups detected. Predictive capability of the selected model was excellent (ROC = 0.807), and prediction accuracy ranged from 70.2% to 73.7%. Cross-validation of the selected model with other population estimation methods resulted in comparable estimates. Future applications of our model should be applied cautiously if characteristics of the area (e.g., vegetation cover >50%, snow cover >90%, group sizes >16 elk) differ notably from the range of variability in these factors under which the model was developed.

Golden Eagles (Aquila chrysaetos) have been identified as a potential predator of endangered San Joaquin kit foxes (Vulpes macrotis mutica), but only one case of such predation has been confirmed. In a recent study on San Joaquin kit foxes, we documented 6 cases of putative predation by Golden Eagles on kit foxes and provided our evidence for each. Golden Eagle predation on kit foxes is most likely to occur in the spring when kit foxes and their pups are frequently aboveground during the day. Such predation is more likely to occur around the margins of the San Joaquin kit fox range, where suitable kit fox habitat abuts suitable nesting habitat for Golden Eagles.

During the last century, the distribution of the woodchuck (Marmota monax) has expanded westward in parts of the Great Plains. Expansive grasslands of the Great Plains were formerly a barrier to forest-dwelling species, but changes since European settlement have enabled some woodland species to colonize the region. By 2000, woodchucks generally reached across the central portion of Nebraska. We compiled new county records and estimated the continued westward expansion rate of this large, diurnal squirrel in Nebraska. We documented new records of M. monax along much of the former western distributional limits in central and southern parts of the state, including a large westward movement along the Platte River into central Keith County. Westward movements appear to follow wooded rivers and their tributaries throughout the state. We estimated that in the last 18 years, M. monax expanded westward along the Platte River from central to western Nebraska at a rate of 9–13 km/year. If not already present in northeastern Colorado, M. monax could reach the Colorado border in <5 years. We acquired many records of M. monax reported as nuisance/damage control to the Nebraska Game and Parks Commission. We suspect that as this species continues to advance westward in the state and other areas of the Great Plains, more residents will report this species as a nuisance. Although a novel species in much of this grassland region, M. monax will provide habitat for a number of other species with its elaborately constructed burrows.

The northern long-eared myotis (Myotis septentrionalis), a federally threatened species, occurs in extreme northern, eastern, and southern Nebraska. These regions vary in climate due to geographic location, topography, and elevation. During a 1-week period in early July 2015, we surveyed bats across the state and observed striking variation in the reproductive status for M. septentrionalis. We examined whether or not growing degree days, an abiotic climatic factor used mainly for agricultural practices, was associated with this reproductive variation in a mammalian species. In early July, we captured only pregnant females in the Pine Ridge region of northwestern Nebraska, the region with the lowest number of growing degree days. In contrast, we captured both lactating females and flying young along the Republican River in south-central Nebraska near the border with Kansas, an area with a high, but intermediate number of growing degree days. Along the Missouri River, in extreme east-central Nebraska, along the border with Iowa, we documented lactating females with no evidence of volant young. This locality had the highest number of growing degree days. Phenotypic plasticity in timing of births for M. septentrionalis appears to be, in part, related to climatic differences across Nebraska, a relationship commonly observed for plants and invertebrates. Our study demonstrates that reproductive phenology can vary significantly across the distribution of a species and needs to be considered when making management decisions for imperiled species. Delayed reproduction in cooler regions of the species' range presents risks to reproductive female M. septentrionalis and their nonvolant offspring, even with current protective measures. In areas with short growing seasons, restrictions on the timing of tree-cutting should be expanded beyond 31 July in more northerly parts of the species' distribution, so as not to hinder reproductive success during the time when juvenile bats are unable to fly.

The Wild Turkey (Meleagris gallopavo sspp.) is a galliform historically distributed throughout the Sierra Madre Occidental, Sierra Madre Oriental, and central Mexico. However, it is currently extirpated from much of its original range. Herein, we report the presence of Wild Turkey in temperate forests of the Sierra Gorda Biosphere Reserve of Guanajuato (SGBRG). We also highlight the importance of our observations in the context of possible natural dispersal and potential range recovery of suitable areas within the historical range in the interior of Guanajuato State. As a result of a wildlife survey program in the SGBRG, a set of 8 photographic records provided evidence of 4 females, 3 males, and 1 juvenile. These records are encouraging, since the species was believed to be extirpated from the wild in this state.

The long-tailed weasel (Mustela frenata) is a generalist predator that feeds mainly on rodents and rabbits. However, predation on Peromyscus rodents has been reported mostly at the genus level and records are scarce. In April 2018, we made a field trip to Laguna Bélgica Educational Park, Chiapas, to capture, handle, and study mammalian wildlife species. We set 15 Sherman traps 5 m apart on a 70-m linear transect for one night. One male M. frenata was captured along with a dead Mexican deer mouse (Peromyscus mexicanus) in the same trap. The rodent had incision marks on the skull, indicating that it had been captured by the mustelid. This new data point enhances the existing information regarding predation habits of M. frenata on P. mexicanus in Chiapas and could elucidate the weasel's ecological role as a biological control on rodent populations.

Wildfire activity in the western United States has increased in recent decades and is predicted to continue increasing. As wildfires cause landscape-level habitat modifications, understanding how wildlife respond to these disturbances is crucial. The Preble's meadow jumping mouse (Zapus hudsonius preblei) is listed as federally threatened, but little information is available on population responses to wildfire. We conducted live-capture surveys prior to and following a natural low-severity fire in eastern Wyoming. Although we did not detect jumping mice in the year following wildfire, we documented a breeding population both immediately prior to and 2 years following fire. Captures of other small mammals varied greatly, with >7 times as many captures 2 years postfire compared to other years. Understanding the effects of disturbance on population persistence is vital not only to ensure conservation objectives are met for this threatened species, but also to evaluate impacts of changes in fire activity to ecosystems overall.

Knowledge of a species' home range size is useful for numerous areas of study, including body-mass scaling, metabolic requirements, and conservation. Notably lacking are home range size estimates from desert habitats for 2 common mammals, Sylvilagus audubonii and Lepus californicus. I estimated daytime, nighttime, and 24-h home range sizes using telemetry in the Chihuahuan Desert of south central New Mexico. For both species, estimates were larger in nighttime than in daytime, and estimates for S. audubonii were larger for males than for females. I found no evidence for home range “cores.”