The lesser prairie-chicken (Tympanuchus pallidicinctus) is a grassland grouse of semiarid regions. Use of free water has been hypothesized as necessary for egg formation during drought. We assessed the use of hydrogen isotopes (deuterium, δ²H) to determine if female lesser prairie-chickens use and incorporate free water during egg formation by testing the relationship between isotope ratios in available free water and eggshells. We collected eggshells from 124 nests and 282 free water samples from three sites in Kansas in 2013 and 2014. Eggshells had δ²H values similar to free water in the year of severe drought but were dissimilar the year with lessened drought severity. With an established link between lesser prairie-chicken eggshells and free water during severe drought, we have identified a mechanism behind observations of lesser prairie-chicken water use. We have demonstrated that hydrogen isotopes can be used to test research questions related to use of free water.

We examined the indirect effects of reintroduced black-tailed prairie dogs (Cynomys ludovicianus) on resident kangaroo rat (Dipodomys) populations. We used the Giving-up Density theory to quantify kangaroo rat foraging on a black-tailed prairie dog colony vs. foraging near the colony edge or in the surrounding native habitat. This approach allowed us to assess the influence of black-tailed prairie dogs on kangaroo rat foraging activity. Our results showed a greater foraging preference off-colony in most seasons. Kangaroo rats visited off-colony feeding trays more frequently and collected a greater mean mass of seed as well. This indicated that kangaroo rats perceived the area off the prairie dog colony as having a lower foraging cost than the on-colony or colony edge locations. Our data suggest that from the perspective of the seed-eating kangaroo rat, the colony is not viewed as high quality habitat. Both prairie dogs and kangaroo rats have been described as keystone modifiers in grassland ecosystems. What impact the reintroduction and management of one keystone species might have on another keystone species deserves additional consideration as we attempt to restore arid grassland ecosystems.

In 1956, and again in 1988, breeding pairs of rock wrens (Salpinctes obsoletus) were observed in Churchill, Manitoba, beyond their previously known breeding extent. It has been suggested that these and other vagrant rock wrens might have been accidentally transported in railroad boxcars. Alternative explanations include: 1) that rock wrens are prone to vagrancy during migration and dispersal, and 2) that the species is expanding its range via hydrographic or human-made corridors. I compiled northern and eastern vagrancy records from May 1898 through November 2015 for rock wrens and four other bird species with similar ranges. I calculated the distance of each sighting to the nearest railway and hydrographic features, compared these distances among species, and identified vagrant clusters. Rock wren vagrants were not significantly different from vagrants of lazuli buntings (Passerina amoena) or Bullock's orioles (Icterus bullockii) in their proximity to railways. Results suggest that vagrancy rates of rock wrens are similar to those of sage thrashers (Oreoscoptes montanus) and green-tailed towhees (Pipilo chlorurus), and vagrancy is likely driven by landscape factors rather than the use of railway corridors or accidental transport in freight cars. Proximity of vagrant rock wrens to lakes, reservoirs, rivers, and streams indicates that these and associated habitat features may act as travel and dispersal corridors.

Quantifying movement of nonnative fish predators is needed to understand the spatial and temporal scale of their impacts on native species. We used radiotelemetry to document nonnative flathead catfish (Pylodictis olivaris) movement at hourly, daily, and seasonal time scales from May 2014 to June 2015 in the upper Gila River basin, New Mexico. Movement varied among individuals, with a large proportion (45%) moving <100 m from tagging locations, while some others moved substantial distances (7,355–42,840 m) downstream into warmer river reaches before winter. Average nightly movements were typically short (5 m) and no fish moved >80 m in one night. Archival radiotags recovered from three individuals indicated that activity was greatest in summer and autumn during the evening, but we also observed some late-afternoon activity. Additionally, abnormally high activity during 8–12-h periods often coincided with increases in river discharge. Temperature was exponentially correlated with activity, with sharp increases of activity occurring between 17.8° and 19.6°C. Although the majority of flathead catfish in this study only moved short distances, we demonstrated their capacity to travel large distances and showed movements are likely triggered by changes in flow and temperature.

I studied growth and longevity of the C₃ drought-deciduous shrub Fouquieria splendens (ocotillo) growing in the Chihuahuan Desert in New Mexico for 22 years through the analysis of rings produced in trunks and stems. Ocotillos studied had 1–64 stems longer than 40 cm, maximum stem lengths of 50–370 cm, and 21–107 growth rings in their trunks. Although trunk rings were positively related to stem rings immediately above the trunks, the base of the largest stems immediately above the trunks had up to 58% fewer rings than the trunks. One growth ring was added to every existing stem segment only in years when a new terminal segment was produced on that stem, and adjacent segments produced in the same year had only one growth ring each. While the 107 growth rings in the trunk of the presumably oldest ocotillo in this study closely match the oldest ocotillo age derived from direct evidence (104 years), the challenge now is to discover whether ocotillo trunk rings really are annual rings.

Sand shinnery oak (Quercus havardii) prairies are increasingly disappearing and increasingly degraded in the Southern High Plains of Texas and New Mexico. Restoring and managing sand shinnery oak prairie can support biodiversity, specific species of conservation concern, and livestock production. We measured vegetation response to four treatment combinations of herbicide (tebuthiuron applied at 0.60 kg/ha) and moderate-intensity grazing (50% removal of annual herbaceous production) over a 10-year period in a sand shinnery oak prairie of eastern New Mexico. We compared the annual vegetation response to the historical climax plant community (HCPC) as outlined by the U.S. Department of Agriculture Ecological Site Description. From 2 to 10 years postapplication, tebuthiuron-treated plots had reduced shrub cover with twice as much forb and grass cover as untreated plots. Tebuthiuron-treated plots, regardless of the presence of grazing, most frequently met HCPC. Tebuthiuron and moderate-intensity grazing increased vegetation heterogeneity and, based on comparison of the HCPC, successfully restored sand shinnery oak prairie to a vegetation composition similar to presettlement.

We investigated the phenology of adult angel lichen moths (Cisthene angelus) along a 364-km long segment of the Colorado River in Grand Canyon, Arizona, USA, using a unique data set of 2,437 light-trap samples collected by citizen scientists. We found that adults of C. angelus were bivoltine from 2012 to 2014. We quantified plasticity in wing lengths and sex ratios among the two generations and across a 545-m elevation gradient. We found that abundance, but not wing length, increased at lower elevations and that the two generations differed in size and sex distributions. Our results shed light on the life history and morphology of a common, but poorly known, species of moth endemic to the southwestern United States and Mexico.

Mexico has a high amphibian diversity (360 species), but several regions of the country remain relatively poorly studied. We document the anuran fauna for the Marabasco River Basin, in Jalisco and Colima, Mexico. Between June and November 2012, we collected 13 species of anurans from 3 sites in the Marabasco, including Lithobates pustulosus, L. forreri, and L. neovolcanicus, which are all species with conservation priority. The anuran community of the Marabasco Basin could be threatened by mining activities and other anthropogenic activities. This is the first published report on the anuran community composition for this basin.

We report the unusual observation of an adult bald eagle (Haliaeetus leucocephalus) in southwestern Nuevo León, Mexico, in the Chihuahuan Desert south of known distribution of the species in the Mexican Plateau. The bald eagle was perched over natural grassland vegetation near croplands at the edge of a Mexican prairie dog (Cynomys mexicanus) town in ejido El Potosí. Identification was made in the field, and the sighting recorded by photograph on 11 January 2015.

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.

Nine-banded armadillos (Dasypus novemcinctus) are nocturnal, semifossorial, insectivorous mammals that historically live in warm climates but have been moving northward over the past 150 y. As armadillos move into more-temperate climates, behavioral adjustments occur in response to decreasing temperatures. Observations in northern latitudes have noted more activity during the daytime in the winter, indicating a shift in circadian rhythm. Such behavioral plasticity may allow individuals to forage when temperatures are optimal for thermoregulation. We recorded armadillo activity for 6 mo using game cameras. We created nocturnal, crepuscular, and diurnal activity indices and then plotted them as a function of time. We compared temperatures of when armadillos were photographed to temperatures when other animals were photographed. Analyses suggest that a seasonal shift in circadian rhythm does occur and that air temperature is an important factor. Although armadillos have previously been reported to have lunar phobia, we saw no evidence of this.

Two genetic lineages of the hispid cotton rat, Sigmodon hispidus, form an area of contact at one location in eastern Texas, with hybridization occurring, but the position of the contact zone in other areas of the United States remains unknown. The purpose of our study was to identify the location of the contact zone at its southernmost point. We employed a nuclear DNA fingerprinting technique, amplified fragment length polymorphism (AFLP), using 20 specimens collected from Orange, Brazoria, and Matagorda counties, Texas, along with reference specimens representative of the two lineages. Our results showed that in southeastern Texas the contact zone occurred in the vicinity of Galveston Bay.

The Ponto-Caspian Cordylophora caspia (Pallas, 1771) is a euryhaline, invasive hydroid reported to occur for the first time in Missouri. We collected a colony of C. caspia on 3 December 2013 from substrate exposed to flow at an inspection area of Bagnell Dam, which impounds Lake of the Ozarks (22,460 ha) in the Osage River drainage basin. Although the ultimate ecological consequences associated with C. caspia invasion of freshwaters in North America are unknown, C. caspia is capable of fouling water management infrastructures and, therefore, monitoring the occurrence and distribution of this invasive hydrozoan is warranted.

Presence of cave crickets is important for health and stability of karst ecosystems. Our study represents the first long-term monitoring of cave crickets at Cave X. Our results add necessary information regarding an important nutrient-cycling species in a central Texas karst ecosystem. Nymphs were the most abundant size class during the study, followed by juveniles, and large adults were least abundant. Relative abundance of cave crickets showed a trend with temperature and humidity.

The endohelminth community of the Mayrán carp, Gila conspersa, collected in the Aguanaval river basin, Central Mexico, was described at the infracommunity and component community levels. Helminth fauna consisted of the species Bothriocephalus acheilognathi, Rhabdochona canadensis, and a Spiroxys species. Among them, the introduced tapeworm species B. acheilognathi was the most frequent and abundant species while remaining taxa were rare and found at low mean abundance values.