Custom camera traps were positioned at American pika (Ochotona princeps) haypiles in 12 warm, low-elevation locations of eastern California over 5 years and during warm and cold seasons. These camera traps detected 26 mammal and 10 bird species, including 4331 pika events as well as visits by 16 sympatric herbivores and 7 pika predators. Camera traps documented pika occupancy at some sites that had been evaluated from field surveys as extirpated, and they also confirmed field assessments of extirpation at other sites. Individual pikas could be distinguished by scars, size, and pelage diagnostics, allowing animals to be followed through sequences of photos and enabling behavioral interpretations and documentation of winter and warm-season activities. Temperature measurements at haypiles and talus interiors corroborated prior findings that rocky interiors are much cooler than surfaces, have highly attenuated daily temperature fluctuations, and offer refuge for pikas from high daytime temperatures. Nocturnal activity was recorded for pikas as well as for many other species, but we found little evidence that night activity of pikas at haypiles increased when prior day temperatures were excessively warm. The capacity of pikas to be active at all times of the day adds to their resilience in the face of predators, foraging needs, and changing climates.

Recent interest in protecting pollinators has led many organizations to plant milkweed to support monarch butterflies. However, little is known about what bee species might also benefit from milkweed plantings. Here I compile a list of bee species that have been collected on milkweed flowers. I compiled these data by searching large online databases and regional collections and supplementing with field collections. At least 282 different bee species have been collected on milkweed. Milkweed flowers can provide an important nectar resource for foraging bees, particularly in arid regions and in dry times of the year.

Barney Hot Springs is a thermal spring in the headwaters of the Little Lost River drainage in central Idaho. Tropical fish have been released into Barney Hot Springs, and several species have established self-sustaining populations. The objectives of this study were to determine the current community assemblage of tropical fish in Barney Hot Springs and to assess species composition and extent of downstream distribution of tropical fish in Barney Creek. The composition in 2017 consisted of Amelanic Convict Cichlids Amatitlania nigrofasciata, Mozambique Tilapia Oreochromis mossambicus, Zebra Mbuna Maylandia zebra, and Green Swordtails Xiphophorus hellerii. Total abundance of all fish species was estimated at 12,043 fish (95% CI 9807–15,600), with Green Swordtails making up 68% of the population, Zebra Mbuna 20%, Convict Cichlids 9%, and Mozambique Tilapia 3%. In Barney Creek, fish were collected within 800 m of Barney Hot Springs. In March 2018, a rain-on-snow event occurred that resulted in a fish kill. In fall 2018 after this event, Convict Cichlids, Green Swordtails, and Goldfish Carassius auratus were collected. Overall abundance was estimated at 1972 fish (95% CI 1757–2227), with Green Swordtails and Goldfish each composing 50% of the population; no Convict Cichlids were recaptured, so abundance could not be estimated. In Barney Creek, fish were collected within 400 m of Barney Hot Springs. We documented current changes to the fish community assemblage of Barney Hot Springs and Barney Creek that were driven by colonization (i.e., introduction of aquarium fish) and by local extinction through species interactions and stochastic events. Currently, we do not know the impact that the introduced fish fauna of Barney Hot Springs may have on native species or ecosystem function.

Sagebrush identification can be improved by using a relatively easy ultraviolet (UV) light test on specimens. Sagebrush produces a variety of water-soluble polyphenols called coumarins, which fluoresce a blue color under UV light and can help differentiate species, subspecies, and hybrids. We tested 16 different sagebrush taxa (including species and subspecies) from herbarium specimens and found 3 taxa (low sagebrush, Artemisia arbuscula; Wyoming sagebrush, A. tridentata wyomingensis; and basin sagebrush, A. t. tridentata) that were often misidentified. We show that the UV light test can greatly improve identification of these species. Moreover, given that the UV+ chemicals that discriminate taxa are also considered an indirect biomarker of sagebrush palatability for some herbivores, the UV light test can be used to predict forage quality for threatened species like sage-grouse (Centrocercus spp.) and pygmy rabbits (Brachylagus idahoensis). Collecting voucher specimens of sagebrush at wildlife study sites and comparing their UV intensity to historical herbarium specimens could help identify both current and changing availability of palatable sagebrush for wildlife. We found that even herbarium specimens >80 years old still fluoresce under UV light.

The San Bernardino flying squirrel (Glaucomys oregonensis californicus) is a California Species of Special Concern restricted to montane forests of southern California. We confirmed the distribution of this species in residential areas of the San Bernardino and San Jacinto Mountains with the assistance of citizen scientist volunteers. Project participants placed motion sensor camera traps near bird feeders on their property and uploaded their results to a project webpage and associated iNaturalist project. Flying squirrels were documented at all sites monitored in the San Bernardino Mountains but were not detected in the San Jacinto Mountains, consistent with survey results in recent decades. Forest structure plots between the 2 ranges differed in tree density, tree height, litter depth, and canopy closure, but it is unclear whether these differences alone can explain the lack of detections in the San Jacinto Mountains. Habitat in residential areas may provide subsidized food and water resources that are attractive to flying squirrels and important to their persistence, especially in seasonally dry forests and areas subject to prolonged drought, such as those in the study area.

Bat species diversity within the United States is greatest in the Southwest, with approximately 30 species present. At least 16 of these bat species hibernate and are susceptible to white-nose syndrome (WNS), which is caused by the fungus Pseudogymnoascus destructans. Since 2006, millions of bats from 35 U.S. states and 7 Canadian provinces have died from WNS. In previous studies of external surfaces of bats sampled from southwestern states, Actinobacteria were detected that were shown to have antifungal properties against P. destructans in laboratory testing. These studies motivated us to expand our research to sites that represent possible gateways for P. destructans to enter the Southwest so that we could establish a baseline of bat microbiota before the arrival of WNS. We surveyed for the presence of bats and their external microbiota at 3 national parks and monuments located in southeastern Colorado and northeastern New Mexico. Our results document new occurrence records of bat species and their external bacteria at each sampling location. Additionally, we provide insight on the composition of bat external microbiota in the absence of P. destructans, while revealing information about the Streptomyces and other possible native defenses of bats against P. destructans at a gateway into the Southwest.

The relationship between fishers (Pekania pennanti), fire, and fuel management in the Sierra Nevada region is complex and highly controversial, and the recent listing of southern Sierra Nevada fishers as endangered has brought this issue to the forefront for many land managers. While wildfire is a natural component of the historic disturbance regime in the dry, mixed conifer forests of California, it also has the capacity to destroy large swaths of suitable habitat and to fragment tenuous populations, particularly given recent shifts in wildfire scope and severity. Therefore, balancing fuel reduction with habitat conservation requires careful consideration of spatial and temporal context, cumulative effects, and management prescriptions. There are several unresolved questions pertaining to fishers, including how and when fishers begin to reuse postfire landscapes and whether this information can be applied to postfire efforts to restore habitat connectivity and limit negative impacts of population fragmentation. To better understand fisher response to postfire landscapes, and to provide land managers with guidance regarding habitat restoration efforts, we investigated fisher recolonization behavior in and around 2 recent Sierra Nevada wildfires. We hypothesized that fisher use of postfire landscapes would be driven by at least 1 of 4 primary variables: prefire habitat quality, fire severity, topography, and time since fire. We developed 5 hypotheses regarding how fishers would begin to explore postfire landscapes and tested them using a combination of fine- and coarse-scale analyses based on data collected using scat detection dogs. At fine scales, the strongest relationship we observed was the combination of fire severity and landscape curvature on fisher scat location. At coarser scales, fisher colonization rates reflected avoidance of areas dominated by higher-severity fire, and fishers had a higher probability of being found in areas with larger and more contiguous patches of low-severity fire. Our results suggest that fisher use of postfire landscapes may center on low-severity or unburned islands (i.e., fire refugia/fire skips) and on fine-scale topographic features associated with landscape concavity, such as ravines or topographic depressions. Efforts to promote a sustainable low- to mixed-severity fire regime that creates habitat heterogeneity and forest resiliency can support fisher conservation in this region, and restoration efforts that capitalize on connecting fire refugia using microtopography as a foundation may facilitate habitat connectivity for fishers more rapidly than traditional methods.

The invasiveness of nonnative taxa can vary across a landscape due to environmental gradients, suggesting that location-dependent management strategies may be more effective at reducing spread compared to a “one size fits all” approach across the entire introduced range. Using bait stations placed along linear transects within habitat preserves, we tested for effects of ecoregion, vegetation, soil moisture, habitat edge type (i.e., moisture source), and distance from edges on the presence of the invasive Argentine ant Linepithema humile in San Diego County, California, a region with high indigenous biodiversity and numerous rare and protected species. Our results showed an inverse relationship between the presence of native ant species and the presence of the Argentine ant across ecoregions, with the latter reaching peak abundance in the coastal terrace. Argentine ant presence was negatively associated with distance from all edge types regardless of location, but the magnitude of this effect varied among ecoregions. In the xeric foothill and inland valleys, the probability of occurrence was nearly 0 at distances of 200 m and 750 m from moisture edges, respectively, whereas in the coastal terrace, the probability remained above 0.80 at distances up to 1.25 km. When compared to previous studies at different spatial scales, these findings provide an alternative perspective on the invasiveness of the Argentine ant at the landscape level. Our results further suggest that efforts to control spread in regions with a Mediterranean climate may be more successful in inland areas, where the ant is likely to have lower environmental tolerance and native ant species may be better able to generate biotic resistance. In contrast, different tactics and expectations may be necessary for coastal areas, where the same constraints are diminished or absent.

This paper reports on the subsurface burrowing of the desert-dwelling land snail Helminthoglypta greggi in the western Mohave Desert. By excavating into the soil layer, we found that the majority of live snails were burrowed into the soil beneath rocks as well as shrubs, and in both disturbed and undisturbed areas. Live snails were found as deep as 50 cm in the soil layer, and shells as deep as 55 cm. Densities averaged 4.3 live snails per square meter of surface area and 10.1 snails per cubic meter of excavated soil. When these densities are multiplied by a conservative habitat estimate, these snails may number in the millions. Burrowing into the soil layer during wet winter periods allows these snails to escape lethally high temperatures in summer, lethally low temperatures in winter, and desiccation in all seasons. The significance of these findings is twofold. First, it is essential that soil sampling be included in surveys for other Helminthoglypta, as well as for other land snails inhabiting arid environments, or their population number, occupancy, and habitat breadth may be underestimated. Second, like H. greggi, it may be that other species of land snails have been considered rare simply because of inadequate sampling and incomplete understanding of the nature and extent of their habitat use.

Because wild rodents often harbor zoonotic pathogens that can be transmitted via saliva, urine, or feces (e.g., hantaviruses), researchers can be at risk when collecting rodent blood or tissue samples that are required for innumerable assays (e.g., infection status, hormone assays, etc.). I describe how inexpensive, readily available 50-mL centrifuge tubes can be easily modified to create a handling tube for the safe restraint of small rodents while a blood and/or tissue sample is collected from the tail. This approach has been used to successfully sample thousands of deer mice (Peromyscus maniculatus), the primary host for Sin Nombre virus, a zoonotic disease that is pathogenic for humans.

We describe the first recorded observations of courtship behavior of the meadow jumping mouse (Zapus hudsonius) made in wild-caught and captive-reared animals. Male meadow jumping mice performed a series of courtship behaviors upon approach to the female, including rapid fanning of the muzzle with the forelimbs, self-grooming, muzzle fanning, retreat, and eventual mounting attempts. During courtship, female jumping mice may retreat, ignore the courting male, or bat at the male with forelimbs until the male retreats. Active rejection of the courting male by the female is suggestive of female mate choice in this species.

The lesser long-nosed bat (Leptonycteris yerbabuenae) previously was known only from extreme southwestern New Mexico in southern Hidalgo County. Herein, we documented L. yerbabuenae from northern Grant County along the Gila River on the southern edge of the Mogollon Plateau, which represents a 110-km range expansion to the north. We captured mostly volant young-of-the-year (68.5%) and adult females (25.9%) as well as a few adult males (5.6%) in September 2019. With assistance from local residents, we have evidence that nectar-feeding bats have been using hummingbird feeders in the area at least since 2014 and are a relatively new arrival to the area. In 2019, the latest observation of bats emptying hummingbird feeders at our study site was on 25 October, the latest reported date for the presence of this species in the state. Fur coloration on the back and head of volant young was dull gray compared to the richly orange- and brown-colored adults. Forearm lengths were shorter and body weights lighter in young compared to adults. It is unclear whether this species bears and/or raises its young in the Gila area or whether the documented individuals represent those dispersing from maternity roosts after the young become volant, a common late-season behavior for this species in the northern reaches of its distribution. Our documentation of this nectar-feeding bat adds to the high diversity of bat species associated with the Mogollon Plateau in southwestern New Mexico.

The more than 60 species in the family Ardeidae (herons, egrets, and bitterns) are known to be very creative at catching prey. Kushlan () describes a total of 38 feeding behaviors for this family. Each species uses several feeding methods, but only 6 species, or about 10% of the family, are known to attract fish by vibrating their bills in water, a technique first described by . This makes bill-vibrating one of the least common feeding tactics in Ardeidae. On 10 May 2019, I observed and photographed an adult Great Blue Heron (Ardea herodias) foraging by bill-vibrating at a large pond in Dead Horse Ranch State Park, near Cottonwood, Arizona. Bill-vibrating has not previously been reported in this species.

Domestic dogs (Canis lupus familiaris) and cats (Felis catus) in natural reserves can affect wild mammal populations through predation, diseases, and disturbance, particularly when habitat patches are small. In Estero El Salado, a remnant mangrove in Puerto Vallarta, Mexico, we used camera trapping to obtain independent observations (n = 1224) to determine abundance, spatial overlap, and activity of medium-sized mammals (domestic dog, domestic cat, northern raccoon [Procyon lotor], Virginia opossum [Didelphis virginiana], gray fox [Urocyon cinereoargenteus], nine-banded armadillo [Dasypus novemcinctus], and jaguarundi [Herpailurus yagouaroundi]). Our efforts constitute the first photographic record for the reserve. Relative abundance (capture frequency referred to 100 trap-days) was largest for raccoons (62.11), followed by dogs (13.31) and cats (5.28). Racoons and cats showed large spatial overlap (0.951), as did nine-banded armadillo and foxes (0.973). Dogs and cats showed different activity patterns from all wild species (P < 0.05) but were similar to each other (P = 0.408), with large temporal overlap (82.8%). Wild species also displayed large temporal overlap (i.e., opossums–raccoons, 80.6%). Wild mammals were predominantly nocturnal, whereas dogs were active throughout the 24-h day/night cycle and cats were mainly crepuscular, suggesting that wild species might avoid domestic species by displaying differential activity patterns. We propose control measures within and around the reserve and an investigation of the possible effects of domestic species on wild species through studies of diet and parasites.

Foothill Yellow-legged Frogs (Rana boylii) have experienced extreme range-wide declines in recent decades. This stream-dwelling species is thought to be in decline primarily due to the alteration of streams through anthropogenic water development, the effects of which may be exacerbated by climate change. Although R. boylii has long been considered an obligate inhabitant of perennial streams, recent observations indicate that this species exhibits greater behavioral plasticity in habitat use, particularly for reproduction. Herein, we report on several observations of R. boylii using atypical habitat for both refuge and reproduction. We found several R. boylii individuals reproducing within lentic habitat over a several year period. We also found up to 27 egg masses of R. boylii in a primarily mud-substrate intermittent stream, where the species bred and recruited individuals in 5 of 10 years. Behavioral plasticity in the use of habitat types described herein indicates a possible search bias in traditional Rana boylii surveys. Our observations may have implications for future assessment of R. boylii habitats and for species recovery.