The cytochrome-b gene was sequenced and data were analyzed for 104 Perognathus from localities in Mexico, Arizona, California, New Mexico, Oklahoma, and Texas to evaluate the validity of P. flavus and P. merriami and to assess the occurrence of species of Perognathus in Oklahoma. Unweighted-parsimony, minimum-evolution, maximum-likelihood (TrN I G), and Bayesian analyses revealed seven well-supported terminal clades corresponding to currently recognized species of Perognathus. Results validate recognition of P. flavus and P. merriami as distinct species, document the occurrence of P. merriami within Oklahoma, and reveal a second potential contact zone between P. flavus and P. merriami in the Oklahoma Panhandle.

We present the first robust estimates of apparent survival of western cottonmouths (Agkistrodon piscivorus leucostoma) in central Texas. Estimates presented were obtained using the Cormack–Jolly-Seber Model that accounts for detectability. Apparent annual probability of survival of western cottonmouths located at Honey Creek, Comal County, Texas, a spring-fed stream flowing 3.2 km to its confluence with the Guadalupe River, was 0.81 and was consistent with estimates for similar species of snakes. Despite low probability of detection (0.12) and relatively small sample (n  =  51), the estimate of survival was reasonably precise (coefficient of variation was 4%). One benefit of our study is that we used a long-term dataset (11 years) that encompassed multiple floods and droughts, and therefore, represents a relatively wide range of conditions to which western cottonmouths are exposed at this locality.

We used radiotelemetry to document and compare activity and movement between the western spotted skunk Spilogale gracilis, and the striped skunk Mephitis mephitis in Texas. Mephitis mephitis had a higher rate of movement than S. gracilis. Both species had highest rates of movement during autumn, coinciding with dispersal of young. With the exception of summer, M. mephitis was significantly more active than S. gracilis and generally took shorter breaks during nightly activity. We documented statistical differences in activity between species for all seasons. Highest activity of one species occurred during lowest activity of the other species, which may indicate avoidance of the larger more-dominant species, M. mephitis, by S. gracilis.

Studies of birds in winter are rare in wildlife ecology despite winter being a critical time for birds. We examined winter assemblages of birds in ponderosa pine (Pinus ponderosa) forests of northern Arizona following prescribed fire. We conducted point counts on two study sites in northern Arizona from mid-October to mid-March 2004–2006. Each site had one unit treated by prescribed fire a full growing season before the point counts began, paired with control unit(s) of similar structure. We detected 39 species during the survey. Nine species comprised 81% of all detections; eight of these were year-round residents of the area. Dark-eyed juncos (Junco hyemalis) were the most numerous, comprising 23% of all detections. Assemblages were similar between treatments (Sorenson similarity index  =  0.85) and years (Sorenson similarity index  =  0.85), and rank abundance of species between burn and control units were correlated (Spearman's ρ  =  0.83). Therefore, assemblages of birds in winter were similar among areas treated by prescribed fire and unburned areas of ponderosa pine forests in northern Arizona.

Our objective was to use the 50%-core-area estimation to measure size of home range of urban-breeding white-winged doves (Zenaida asiatica) from two ecoregions in Texas. We collected data on locations using subcutaneously implanted radiotransmitters on 40 white-winged doves in Kingsville, Kleberg County, during 2000, and 40 and 39 white-winged doves in Waco, McLellan County, during 2002 and 2003, respectively. We calculated size of home ranges using bivariate-normal methods. We compared size of home range from 50%-core-area estimations within and between sites, and by sex, using two-sample t-tests following log₁₀ transformation of data to meet the assumptions of normality and homoscedasticity. Generally, estimated size of 50%-core-areas differed significantly between sites but not within sites.

Status of the common muskrat (Ondatra zibethicus) in the southern High Plains and western Rolling Plains has remained uncertain due to a scarcity of records. I examined diversity of riparian habitats, frequency of occurrence of habitats, availability of habitats, and use of habitats by muskrats within an irrigation drainage system in southwestern Oklahoma during prolonged drought. Six major habitats were supported in 31 km of drainage channels. These included, in order of descending frequency, emergent cattails, prairie sedge meadow, cattail-forested transition, forest, turf grass, and pioneer mudflat. Of habitats in drainage systems, 60% were available for muskrats as defined by presence of water. Availability differed among habitats; prairie sedge meadow had highest availability and emergent cattails was the lowest in availability. Use of habitats differed significantly among habitats and was driven by availability.

The eastern fox squirrel (Sciurus niger) is one of 22 non-native species of mammals now successfully breeding in the wild in California. The focus of this study was to describe current and historical distribution of the eastern fox squirrel in the greater Los Angeles metropolitan area (Los Angeles, Orange, and Ventura counties) in relation to their initial point of introduction in 1904. Data were obtained through questionnaires, submissions to websites, direct observations, records of wildlife-rehabilitation centers, and specimens in the Los Angeles County Museum of Natural History. Locations of eastern fox squirrels were geo-referenced on a map to ascertain the current distribution. A time-series distribution map was created to document expansion of the range from the point of introduction to distribution of the species in the greater Los Angeles metropolitan area as of 2004. Distribution of the population in Los Angeles County was expanding at rates of 0.44–3.44 km/year during varying time periods over the 100 years since the introduction. By determining the periphery of the current distribution of the eastern fox squirrel and rate of expansion of the range in the greater Los Angeles metropolitan area, wildlife managers in surrounding communities may be able to anticipate locations where future expansions of the range may occur.

We compared diversity and abundance of small mammals at colonies of black-tailed prairie dogs (Cynomys ludovicianus) and paired non-colony sites. Of colonies of black-tailed prairie dogs in our study area, >80% were on slopes of playa lakes; thus, we used sites of colonies and non-colonies that were on slopes of playa lakes. We trapped small mammals on 29 pairs of sites. Overall abundance did not differ between types of sites, but some taxa exhibited associations with colonies (Onychomys leucogaster) or non-colonies (Chaetodipus hispidus, Reithrodontomys, Sigmodon hispidus). Diversity and evenness of small mammals did not differ between colonies and non-colonies in 2002, but were higher on non-colonies in 2003. Although we may not have detected some rare or infrequently occurring species, our data reveal differences in diversity and evenness of more common species among the types of sites. Prairie dogs are touted as a keystone species with their colonies associated with a greater faunal diversity than adjacent lands. Our findings contradict several studies reporting greater diversity and abundance of small mammals at colonies of prairie dogs. We suggest that additional research across a wider landscape and incorporating landscape variables beyond the immediate trapping plot may further elucidate interspecific associations between black-tailed prairie dogs and species of small rodents.

In Texas, introduced wild boars (Sus scrofa) consume mast crops that are high-quality foods sought by native wildlife. Because mast often is abundant but ephemeral, competition among species is expected. Relative rates of intake among individuals can determine how much mast can be obtained and digested. Our objective was to determine intake of mast by wild boars, white-tailed deer (Odocoileus virginianus), collared peccaries (Pecari tajacu), wild turkeys (Meleagris gallopavo), and raccoons (Procyon lotor). Trials were conducted with pods from honey mesquites (Prosopis glandulosa), acorns from live oaks (Quercus virginiana), and acorns from Shumard oaks (Quercus shumardii). Rate of intake of dry matter (g/min), rate of bites (bites/min), and size of bites (g/bite) were determined for each species. Despite their larger size, wild boars did not have consistently higher rates of intake than species of native wildlife. However, rates of intake for wild boars were among the highest for pods of honey mesquites and acorns of live oaks. Wild boars had low rates of intake for acorns of Shumard oaks, primarily because wild boars removed the shell, which increased handling time and reduced size of bite. Collared peccaries and raccoons also exhibited shelling behavior when consuming acorns, which reduced their intakes as well. White-tailed deer had relatively high rates of intake of mast compared to other species. Wild turkeys maintained the highest rates of bites for acorns of live oaks, which resulted in high rates of intake relative to body mass. The value of mast appears to be related to its size and shape, which may enable some species to attain higher rates of intake of dry matter than possible on browse and other foods. Moderate to high rates of intake of mast by wild boars, coupled with their ability to displace other species from feeding sites and obtain a higher-quality diet by discarding acorn shells should enable them to compete effectively with native species for mast.

Success in competition for a limited food resource can be determined in part by how efficiently a species digests food. We conducted in vivo trials to compare digestive performance by a guild of mast-consuming species in southern Texas: wild boar (Sus scrofa), white-tailed deer (Odocoileus virginianus), collared peccary (Pecari tajacu), wild turkey (Meleagris gallopavo), raccoon (Procyon lotor), and southern plains woodrat (Neotoma micropus). Four individuals of each species were fed commercial pellets and chromium-marked fiber to determine rates of passage. Dry matter and intake of digestible energy, and digestibility of detergent fiber, crude protein, and gross energy (metabolizability for turkeys) were determined for each species. Mean retention and time of passage of 95% of marked fiber were calculated. Digestibility and time of retention by wild boars was similar to foregut-fermenting species and equal to or greater than smaller hindgut fermenters. White-tailed deer and collared peccaries showed similar capabilities of digestion and retention, and also had higher digestibilities of fiber than small hindgut fermenters. Turkeys and raccoons had fast rates of passage and showed little digestion of fiber. Southern plains woodrats had intermediate digestibilities and times of retention. Wild boars are expected to be effective competitors for mast because of their digestive efficiency, large body size, and potential for consumption of large quantities of food.

We intensively sampled fishes from two reaches of the Rio Grande within the Albuquerque Basin (Albuquerque and Belen valleys) during 1998–2001, compared our findings with those from 1984, and compiled a list of all fishes known from the two reaches. Structure of assemblages (richness, diversity, abundance distributions–taxon dominance versus rank abundance) was similar between reaches in 1998–2001, but the faunas had low taxonomic similarity. The nonnative white sucker (Catostomus commersonii), western mosquitofish (Gambusia affinis), and native red shiner (Cyprinella lutrensis) dominated the Albuquerque Valley. Faunal change in the Albuquerque Valley between 1984 and 1998–2001 indicated all native fishes besides the red shiner declined, particularly the Rio Grande silvery minnow (Hybognathus amarus) and longnose dace (Rhinichthys cataractae). In contrast, the red shiner alone dominated the Belen Valley, nonnative fishes were less dominant, and aside from the Rio Grande silvery minnow and longnose dace, native species did not decline. Environmental differences provide a potential explanation for divergence of faunas between valleys, i.e., discharge in spring and summer is higher and substrate is coarser in the Albuquerque Valley. Dewatering, fragmentation by dams, and modifications of the river channel correspond to historical losses of fishes that require fluvial conditions. With the exception of the red shiner and, possibly, the fathead minnow (Pimephales promelas) and slender carpsucker (Carpiodes carpio), native fishes appear to be succumbing to combined stressors of change in habitat, intermittence of streamflow, and interactions with nonnative taxa.

The western pond turtle (Actinemys marmorata) has lost most of its habitat in the Central Valley of California to agricultural activities, flood control, and urbanization. Although a few areas still support this turtle, most habitats are now altered by humans. Aquatic habitats near population centers also may become release sites for a variety of introduced turtles, which could compete with the native A. marmorata. In 1999, 2002, and 2007, I trapped at the Fresno and Hanford wastewater-treatment facilities to determine presence and numbers of A. marmorata at settling ponds in these facilities. I caught 213 A. marmorata at Fresno and 106 at Hanford. No other species of turtles was caught. Turtles at both sites grew rapidly and had a mean size of clutch of 8.2 (Fresno) and 8.5 eggs (Hanford), which are the highest mean size of clutch reported for this species. Although not esthetically appealing to people, both sewage-treatment facilities provide habitat for A. marmorata and these could provide stock for future reintroductions of this species to more natural, rehabilitated aquatic habitats in nearby areas.

Diet of two populations of Sceloporus grammicus was determined from Tilcuautla and La Estanzuela, Hidalgo, Mexico. Diet of S. grammicus is primarily Araneae, Insecta (Coleoptera, Dermaptera, Diptera, Hemiptera, Homoptera, Hymenoptera Lepidoptera, and Orthoptera), Mollusca (gastropods), and Reptilia (Sauria). Hymenoptera and Coleoptera were most frequent in the diet of both populations. These groups were more abundant and more diverse in diet of lizards from Tilcuautla than in those from La Estanzuela. Breadth of diet for males from Tilcuautla was B  =  0.108 and for females was B  =  0.101, and in La Estanzuela was B  =  0.183 and B  =  0.095 for males and females, respectively. Overlap between males and females from Tilcuautla was O_jk  =  1.000, with percentage overlap of 97.0–100%, and for La Estanzuela overlap was O_jk  =  0.938, with percentage overlap of 76.3–100%. Based on the feeding-importance value (ViI), coleopterans and hymenopterans were the most important orders in the diet of S. grammicus for both populations and sexes. Diet of S. grammicus is mainly insectivorous with a tendency to specialization on coleopterans and hymenopterans, but this species could be a generalist at some time during the year as indicated by this study.

The zebra-tailed lizard (Callisaurus draconoides) is a diurnal territorial insectivore from arid areas of North America. The underside of its tail has a series of black bands on a white background; individuals raise the tail to expose the underside as a social signal and to deter pursuit by predators. We characterized variation in banding of the tail within a population of C. draconoides from Sonora, Mexico, and examined the relationship between characteristics and use of the tail. Number of bands on intact tails was 4–10; individuals who have experienced some natural reduction in their tail can lack bands all together. The proportion of the underside of the tail that was black was 0–0.46. For males, snout–vent length and mass were positively correlated with number of bands and mean length of bars on the tail; snout–vent length, mass, and width of head were positively correlated with the proportion of black on tails. Females in better condition (based on residuals from regression of snout–vent length to mass) tended to have more bars on the tail and a wider head; snout–vent length, mass, and width of head were positively correlated with mean length of band. We simulated predator-prey interactions using humans as predators. Males used tail displays more than females. Individuals encountered in the open were more likely to use tail displays. Neither size of body nor natural reduction in tail was related to use of tail displays. During focal observations for females with reduced tails, rates of tail displays were positively correlated with length of tail. Males with intact tails moved more frequently and fed more often than males with reduced tails.

Pallid bats, Antrozous pallidus, glean prey off the ground or from vegetation. During 27 March-19 November 2004, culled parts of prey were collected from under a night roost on Indio Mountains Research Station, Hudspeth County, Texas. Adjacent pitfall traps were monitored concurrently to determine species richness and seasonal abundance of potential prey. Prey representing 44 morphospecies from 4 classes, 13 orders, 25 families, and 34 genera were recovered and identified. Of the identified morphospecies, 29 were unrecorded previously in diet of the pallid bat. Orthopterans were the highest percentage of prey (44.1%), followed by coleopterans (26.8%), and solifugids (16.2%), but most taxa were represented by <4% of the total. Conclusions are that arthropods are the primary food source, but a wide variety of species are consumed, there is occasional predation on vertebrates (three species of lizards), there are statistical differences between amount of prey eaten and abundance of prey in the same geographic area indicating selective foraging behavior, there are seasonal dietary shifts associated with common prey items, and there is geographic variation in diet of pallid bats when compared to studies from other localities within its geographic range.

We examined the percentage of consumption of eggs of the endangered fountain darter, Etheostoma fonticola, by native and nonnative snails from the San Marcos River, Hays County, Texas. Although all snails consumed eggs, non-native Marisa cornuarietis (Prosobranchia: Ampullaridae) and native Helisoma anceps (Pulmonata: Planorbidae) consumed a significantly greater percentage of eggs than non-native Tarebia granifera and Melanoides tuberculatus (Prosobranchia: Thiaridae) and the native Physella virgata (Pulmonata: Physidae). Dramatic increases in M. cornuarietis in the San Marcos and Comal springs may have an adverse affect on populations of fountain darters.

Reports of the giant anteater (Myrmecophaga tridactyla) in Central America, and specifically in Honduras, are sporadic and typically of just one individual. During a 3.5-year (2001–2005) Honduran Program of Biological Monitoring, four new reports of the giant anteater were made in protected areas located in the Honduran Mosquitia in the departments of Gracias a Dios and Olancho with the most sightings made in the proposed protected area of Rus Rus. Three additional reports independent of the Honduran Program of Biological Monitoring are documented herein as well; these reports also are from the protected area of Rus Rus. We conclude that the giant anteater probably has been extirpated from the Caribbean region of Honduras, but remains present in the Honduran Mosquitia in the departments of Gracias a Dios and Olancho.

Piscivory in age-0 smallmouth bass (Micropterus dolomieu) on native species is documented widely; however, few studies report size of prey. On 16 July 2008, we collected a smallmouth bass (65 mm in total length) with a bigscale logperch (Percina macrolepida; 44 mm in total length) in its gastrointestinal tract, from the Pecos River near Puerto de Luna, Guadalupe County, New Mexico. Smallmouth bass are nonnative in New Mexico. Bigscale logperch are listed as threatened in New Mexico, and the ability of age-0 smallmouth bass to take bigscale logperch at least 68% of their total length as prey should raise concerns about stocking smallmouth bass in areas where bigscale logperch and other native species occur.

Few studies have documented behavioral response of small mammals to fire. Here we report use of a nest by an adult Mount Graham red squirrel (Tamiasciurus hudsonicus grahamensis), an endangered subspecies endemic to the Pinaleño Mountains of southeastern Arizona, following a direct lightning strike to a tree. After 2 days, the squirrel nested in this tree and remained in the area for another 136 days. This is evidence that red squirrels may tolerate some degree of fire on the landscape.

We studied reproductive characteristics of two syntopic whiptail lizards, Aspidoscelis marmorata and A. tesselata, inhabiting the northern Chihuahuan Desert. Reproductive characteristics studied were snout–vent length at sexual maturity, size of clutch, and volume of eggs. In A. marmorata, males and females were similar in snout–vent length, but body mass was larger in males than in females. Female A. tesselata were larger in snout-vent length and heavier than female A. marmorata. Mean size of clutch was 3.3 for A. marmorata and 3.5 for A. tesselata. Females of A. marmorata had larger volume of eggs than females of A. tesselata. Data suggest that both A. marmorata and A. tesselata respond to environmental factors of the region in different ways.

Sound production and spawning behavior has not been described in Cyprinella lepida, the Edwards Plateau shiner, although described for other species in the genus. This study documented acoustic signals associated with agonistic and courtship interactions produced by male C. lepida during the breeding season. Females did not produce sounds. Signals were monophasic consisting of one type of call (pulses). All sounds were non-harmonic, low frequency, and often occurred in trains called bursts. Courtship behaviors were characterized by differences in duration and dominant frequency. The exact mechanism of sound production in this species is unknown.

We detected evidence of predation by the Sonora mud turtle (Kinosternon sonoriense) on the Arizona alligator lizard (Elgaria kingii nobilis) and the ground snake (Sonora semiannulata) at Montezuma Well, Yavapai County, Arizona. Lizards have not been reported in the diet of K. sonoriense, and saurophagy is rare in turtles of the United States, having been reported previously in only two other species:, the false map turtle (Graptemys pseudogeographica) and the eastern box turtle (Terrapene carolina). While the diet of K. sonoriense includes snakes, ours is the first record of S. semiannulata as food of this turtle. Ophiophagy also is rare in turtles of the United States with records for only five other species of turtles. Given the opportunistic diets of many North American turtles, including K. sonoriense, the scarcity of published records of saurophagy and ophiophagy likely represents a shortage of observations, not rarity of occurrence.

We discovered a previously unknown population of collared peccaries (Pecari tajacu) in Bastrop County, Texas (30.26245°N, 97.31024°W). Prior to this report, collared peccaries had been reported in western Texas and in the brush country south of San Antonio. There also are introduced populations in several counties in north-central Texas. The newly discovered population was in forests of post oak (Quercus stellata) and black jack oak (Q. marilandica), similar to the oak forest occupied by the population in Trans-Pecos Texas. Range extensions have been documented in northern New Mexico, western Texas, and eastern Texas. Whether or not the population in Bastrop County is an introduction or a range extension is unknown.

We report seven new records of the threatened Mexican hairy dwarf porcupine Sphiggurus mexicanus (formerly Coendou mexicanus) in southwestern Michoacán, Mexico. These records extend northwardly the known distribution of S. mexicanus along the Pacific coast into Michoacán, and constitute the first known occurrences in temperate pine and pine-oak forests. Although additional distributional data are needed, populations of S. mexicanus in western Michoacán may prove important for conservation planning and management of this threatened species.