Desert cottontails (Sylvilagus audubonii) and black-tailed jackrabbits (Lepus californicus) occur in sympatry throughout the southwestern United States and northern Mexico, including in the Chihuahuan Desert. Their ecological niches are similar but separated by variations of diet and microhabitat. To determine if niche separation may be supplemented by differing times of foraging activity, I first tested various lures and baits and determined the optimal attractant for camera stations to be alfalfa hay and apple juice. I then observed desert cottontail and black-tailed jackrabbit activity at baited and control camera stations. Peak seasonal foraging activity occurred in winter for desert cottontails and in spring for black-tailed jackrabbits. Early morning activity peaked in black-tailed jackrabbits 1 h later than in desert cottontails, but otherwise general diel activity levels were similar between the two species. However, times of peak feeding, as determined by comparisons of baited and control stations, were clearly separated. Thus, niche separation between desert cottontails and black-tailed jackrabbits in the Chihuahuan Desert may be increased by differing time distributions of foraging activity.

It has been assumed that populations of Gambusia geiseri in the Colorado River and Rio Grande basins of Texas were introduced from the San Marcos area of east Texas by humans in the 1930s. This was questionable because of the paucity of early records of Gambusia from the region. Further, a congener, Gambusia speciosa, in the Rio Grande basin carries an apparently “foreign” mitochondrial cytochrome b gene (cytb) haplotype most similar to, but 2% divergent from, a haplotype previously reported for G. geiseri in the San Marcos River. This suggested the populations of G. geiseri outside of the San Marcos area might represent a divergent native lineage of the species. To address this, we assessed variation for cytb and a nuclear sequence (S7 intron 1) in G. geiseri from six spring systems supporting the species. The results suggest nonnative status for all populations of G. geiseri outside the Comal and San Marcos rivers. A phylogenetic analysis of cytb haplotypes in Gambusia species from Texas and northern Mexico demonstrates a sister relationship between G. geiseri and a missing ancestor involved in the mitochondrial ancestry of G. speciosa.

The Attwater's prairie-chicken (ATPC) Tympanuchus cupido attwateri is facing rapid extinction. Given their long-standing protected status, little information pertaining to the parasites and diseases of this species is available. In an effort to aid in management strategies, we conducted a helminth survey on ATPC that had been released from captivity between 1999 and 2010 in the Texas City Prairie Preserve, Galveston County, Texas. Birds examined were in various stages of decomposition, ranging from little signs of decomposition to advanced stages. Two hundred fifty nematodes representing three species were identified from 16 ATPC. Dispharynx nasuta was the most prevalent helminth species and occurred in 38% of hosts examined. Heterakis gallinarum occurred in 19% of hosts examined and Capillaria contorta infected 31% of hosts examined. Juvenile ATPC are typically treated with anthelmintics (Ivermectin and Panacur) before release in the wild. Although they spent variable (but limited) time in the environment postrelease, nematode prevalence was high.

Modern climate change will increase temperatures, as well as the frequency and severity of droughts and wildfires across the semiarid montane regions of the southwestern United States. Predictions of reduced habitat suitability and increases in extinctions precipitated by climate change derive from modeled responses to these conditions, especially increased temperatures. What is often lacking are empirical tests of those modeled predictions. Here I report findings from surveys of montane lizard assemblages during a period of increased temperatures, extended drought, and including a wildfire. I selected survey routes that included upper-elevation limits for western fence lizards (Sceloporus occidentalis), granite spiny lizards (Sceloporus orcuttii), and side-blotched lizards (Uta stansburiana), as well as the lower limits for southern sagebrush lizards (Sceloporus vandenburgianus), to measure the extent to which habitat occupancy shifted as drought conditions changed over 4 years. At the onset of drought, the abundance of all species declined. After initial declines, populations stabilized and I observed recruitment, positive population growth, and elevation shifts with only modest increases in rainfall. Once the drought abated, there were further increases in recruitment and population growth, but a colder winter and heavy snows in 2017 were coincident with declines and range contractions in both western fence and side-blotched lizards on the higher-elevation survey route. There was no indication that any of these species' populations were at risk of local extinctions; rather, shifts at range margins and use of microclimates revealed resilience and mechanisms of how these species might deal with future conditions, including occupying climate refugia.

Relatively little has been documented about the seasonal activity, population biology, and foraging ecology of the yellow-bellied watersnake (Nerodia erythrogaster flavigaster). I studied a population of N. e. flavigaster in a riparian bottomland forest in eastern Texas. The male-to-female ratio was 1:1.23. Relative body mass did not differ between sexes but sampling was skewed toward juveniles. Relative tail length was sexually dimorphic with males having longer tails. Captures were highest in the spring months and significantly correlated with soil temperature under cover boards. Maximum prey size increased with snake size but adults still consumed small prey including anuran larvae, demonstrating a telescoping pattern of prey size selection. Approximately 50% of individuals with food had consumed more than one prey item. The data herein provide information regarding understudied aspects of N. e. flavigaster autecology and watersnake ecology in riparian forests.

Nurse-protégé interactions facilitate seedling establishment of many cacti species and might promote spatial aggregation of plants. In June 2014, we analyzed the spatial distribution pattern with Ripley's K-function and the possible association of Astrophytum myriostigma with nurse plants in two populations (Rioverde and Pozas, San Luis Potosí, Mexico). We estimated canopy cover of perennial plant species with a logarithmic scale method and determined the association, size, and orientation of A. myriostigma in relation to nurse plants. Astrophytum myriostigma had an aggregated distribution pattern; approximately 50% were associated with nurse plants at Rioverde and 63% at Pozas, with Hechtia glomerata (Bromeliaceae) being the main nurse plant species in both populations. Cacti associated with nurse plants at Pozas were larger than those not associated, and they did not have any significant orientation in relation to the nurse plant crown. In contrast, the size of associated and nonassociated cacti at Rioverde was similar, but they were established significantly more frequently under the north side of the nurse plant. The association of A. myriostigma with nurse plants is facultative, through either nurse plant protection or open spaces, likely related with abiotic nurses. Understanding nurse plant associations will help target key species for conservation and identify the most likely associations to increase the survival of reintroduced individuals.

During July 2011 we collected an adult striped mullet (Mugil cephalus) from the upper White River in the Ozark Plateau of Arkansas. This is the first record of the species from the upper White River drainage; there is one record from the extreme lower portion of the White River where it drains into the Arkansas River. Eight other previous records of M. cephalus from the state include those from the lower Arkansas, lower Mississippi, upper Ouachita, and Red–Sulphur rivers. The species is listed as S1 (critically imperiled) in the state by the Nature Conservancy.

The greater grison (Galictis vittatta) is one of the least studied Neotropical carnivores. As part of a biodiversity survey in southeastern Mexico, we recorded in a camera trap a greater grison that carried in its mouth a Central American indigo snake (Drymarchon melanurus). Even though we did not find evidence that the snake was consumed by the greater grison in place, it is likely that the species carried the snake to a refuge to be eaten as previously reported with other large prey. If confirmed, this would be the first time that the greater grison has been documented hunting and probably feeding on snakes in Mexico and elsewhere.

Map turtles and sawbacks (Emydidae: Graptemys) are riverine species for which several range extensions have been recently reported. There has been little previous documentation of Graptemys species in the upper Neches River basin in east Texas. In the upper Neches and its largest tributary, the Angelina River, I photographed basking and swimming turtles at highway crossings and captured them in basking traps to establish the ranges of Sabine (Graptemys sabinensis) and false map (Graptemys pseudogeographica) turtles. I obtained voucher photographs of G. sabinensis at 9 of 10 sites visited and of G. pseudogeographica at 6 of 10 sites; new county records number seven and one for the two species, respectively. The two Graptemys species were the predominant basking turtles of the upper Neches river drainage, with G. sabinensis outnumbering G. pseudogeographica overall by ratios of 2.8:1 in visual surveys and 1.2:1 in trapping surveys.

We observed an instance of a greater roadrunner (Geococcyx californianus) capturing a juvenile quail in Mitchell County, Texas, on 7 July 2017. Despite very limited documentation of such events, the potential of roadrunners as predators of quail has long been suspected and requires further investigation.

On 21 September 2012, a dried carcass of a bighorn sheep (Ovis canadensis) was found near Black Mesa in the Oklahoma Panhandle. A complete skeleton (OMNH 55240) was salvaged and represents the first specimen record of the species in the state of Oklahoma.