Populations of ocelots (Leopardus pardalis) have declined during the past century due mainly to loss of habitat resulting in the ocelot being listed as endangered by the United States Fish and Wildlife Service. In southern Texas, the northern distribution of the ocelot overlaps the southern distribution of the bobcat (Lynx rufus). Because bobcats could adversely affect populations of ocelots through interspecific competition, we examined habitat selection of sympatric ocelots and bobcats to determine if habitat partitioning could be functioning to reduce interspecific interactions. Using radiotelemetry, we analyzed macro-scale (vegetative communities) and micro-scale (structural components) selection of habitats by sympatric ocelots and bobcats on Laguna Atascosa National Wildlife Refuge, Cameron County, Texas. We looked for differences in placement of home ranges within the general study area, selection of cover within home ranges, and use of structural components of vegetation within types of cover. There was substantial evidence for habitat partitioning with ocelots selecting areas with >75% canopy cover, while bobcats selected areas with <75% canopy cover. Thus, coexistence between these two species might be facilitated by resource partitioning of habitat.

Shorebirds (Charadrii) spend the majority (ca. 70%) of their lifecycle in wintering and migratory staging areas located on temperate and tropical coastlines; therefore, the implications of habitat loss and destruction require assessment of both marginal and prime habitats in coastal areas. In this study, behavior was used to determine use of habitat within an urban wetland complex located on the Texas coast. Instantaneous scans were used to determine behavior of shorebirds in five habitat types: bayshore, tidal and isolated ponds, estuarine lakeshore, and a salt marsh. Behavior of 22 species of shorebirds representing six guilds was documented. Of the shorebirds observed, 90% were foraging and significantly more were foraging than were engaged in other activities. Foraging occurred significantly more in tidal ponds than in the four other habitats and foraging was greatest in spring. Behavioral observations provided important insight into function of habitat, underscoring the need to incorporate behavioral studies into strategies to monitor shorebirds.

Sand shinnery oak (Quercus havardii) communities, a major component of grassland habitat of birds in eastern New Mexico, frequently are managed with livestock grazing and herbicide application for control of shrubs. We examined nest density, nest-site selection, and daily rate of survival of nests of grassland birds among four combinations of treatments with tebuthiuron (0.75 kg/ha) and a short-duration, rotational-grazing system being used to restore sand shinnery oak communities in eastern New Mexico. During breeding seasons 2004 and 2005, we searched 4-ha subplots in four tebuthiuron-grazing-combination replicates for nests, measured vertical and overhead cover at each nest site and an associated random point, and estimated daily rate of survival of nests using program MARK. Density of nests was similar among all treatments but greater in 2005 than 2004. Although vertical cover differed among treatments and between years, it did not affect selection or success of nest sites. Overhead cover also differed among treatments and between years. Birds selected nest sites with greater overhead cover but this did not influence success of nest, which was low in all treatments. During incubation, daily survival of nests was greater in untreated plots; however, during the nestling period, daily survival of nests was greater in tebuthiuron-treated plots. Neither tebuthiuron nor grazing treatment appeared to adversely affect density of nests of grassland birds or success for the species studied, but the low daily rate of survival of nests in this community bears further investigation.

I tested the circadian activity rhythm of field-captured prairie voles, Microtus ochrogaster, in experimental laboratory chambers. Microtus ochrogaster displayed a circadian rhythm with major activity during the dark period, whether in a normal or reversed photoperiod. When in constant dark and constant light, there was no distinct circadian rhythm; activity was greater when in constant dark than when in constant light. An activity rhythm with little activity during the daylight hours presumably would reduce risk of predation from diurnal avian predators. I propose such an activity pattern contributes to the ability of M. ochrogaster to achieve high population densities in habitats with sparse vegetative cover.

Estimating rates of survival of cougars (Puma concolor) and identifying sources of mortalities potentially enhance management prescriptions. Sport hunting is believed to be the primary cause of mortality in hunted populations of cougars, but little research has evaluated how hunting and other causes of death might influence survival and sources of mortality of these predators in semi-arid ecosystems. We captured and monitored 16 adults (12 males, 4 females) during 2006 and 2007 on two heavily hunted, semi-arid, study areas in north-central Arizona. Rates of survival of adults differed moderately between study areas and years, generally were ≤0.67, and were comparatively low for combined years (≤0.55). One-half of radiocollared adults died during the study, and sport hunting was the primary cause of deaths, followed by intraspecific aggression and collision with vehicles. We hypothesize that sport hunting was the primary factor influencing relatively low rates of survival of cougars on the study areas.

This study was conducted to characterize trophic relationships of small nonnative fishes and to determine if predation by these fishes contributes to the decline of desert pupfish (Cyprinodon macularius), an endangered cyprinodont on the verge of extinction. We sampled 403 hybrid Mozambique tilapias (Oreochromis mossambica by O. urolepis), 107 redbelly tilapias (Tilapia zillii), 32 longjaw mudsuckers (Gillichthys mirabilis), 182 western mosquitofish (Gambusia affinis), 222 sailfin mollies (Poecilia latipinna), 63 shortfin mollies (Poecilia mexicana), and 235 porthole livebearers (Poeciliopsis gracilis) from a natural creek and four agricultural drains during September 1999–December 2001. Evidence of piscivory was in gastrointestinal contents of 14 hybrid Mozambique tilapias, 3 redbelly tilapias, 10 longjaw mudsuckers, 8 western mosquitofish, 2 sailfin mollies, and 8 porthole livebearers. Although digestion often was too advanced for identification of fishes consumed by nonnative fishes, remains of desert pupfish were in gastrointestinal contents of a longjaw mudsucker. Our findings, along with field evidence from other studies that inverse relationships exist between abundances of desert pupfish and nonnative species, are consistent with the hypothesis that predation by nonnative species is contributing to decline of desert pupfish. We suspect that competitive interactions with nonnative fishes might also adversely affect abundance of desert pupfish.

For insectivorous bats in temperate regions, energetic stresses imposed by the thermal environment of a roost might cause bats to be more selective of prey consumed to compensate for increased energetic demands. We collected samples of guano from beneath maternity roosts of Myotis velifer in caves and barns in the Red Hills region of southern Kansas. Caves were cooler than barns and, thus, imposed greater energetic stress on roosting bats. We analyzed food habits to determine if diet was associated with the thermal environment of roosts in caves and barns. Food habits of adult female bats roosting in caves and barns did not differ, suggesting that females are using other methods, most likely a combination of methods, to cope with cooler temperatures in caves.

Survival of chicks of the interior least tern (Sterna antillarum athalassos) has been difficult to estimate due to their semi-precocial development and cryptic coloration. After chicks disperse from the nest, they rarely are relocated. Our objectives were to estimate survival of chicks and study their movement patterns. In 1999, we attached radiotransmitters to 25 chicks and tracked them for 2–19 days depending on retention of transmitter. Because fate could not be determined always when signals were lost, a high and low estimate of survival was calculated. Kaplan-Meier estimates of survival were calculated first by assuming that all lost signals represented mortalities, and second that these transmitters failed and chicks were alive. This resulted in a minimum estimate of 5% of chicks surviving at the end of the study period and a high of 27%. Five chicks fledged, six died, and fate of the remaining 14 was undetermined. Although chicks appeared to allocate a substantial part of their daily movement to nocturnal periods, average rates of diurnal (7.6 m/h) and nocturnal movement (12.5 m/h) did not differ. Chicks primarily moved toward stable sources of water.

We collected 58 species of caddisflies representing 30 genera and 16 families during a 5-year period in Oak Creek, Coconino Co., Arizona. This is the largest number of species of caddisflies reported in any drainage in Arizona and includes >50% of species reported from the state. Species assemblages changed dramatically along the 767-m descent of Oak Creek over a 70-km distance. Discharge records suggest reduced winter and spring surges of water and increased embeddedness of the channel have caused changes in assemblages of caddisflies in Oak Creek over the past several decades. Increased numbers of hydroptilids, hydropsychids, and leptocerids have replaced limnephilids. We conducted a 2-year phenological study at monthly intervals at two sites separated by <400 m in elevation and a distance of 14 km. Spring surges of water played a selective role in larval success and ultimately in number and composition of captures of adults between years. We increased the number of recorded species of caddisflies to 109 in the state. A baseline on assemblages of caddisflies was provided for monitoring changes in health of ecosystem in Oak Creek during the predicted, long-term drought in the Southwest.

Hoary bats (Lasiurus cinereus) exhibit continental patterns of migration that are unique to bats, but details about their behaviors during migration are lacking. We captured 177 hoary bats in spring and early summer 2002 as individuals migrated through the Sandia Mountains of north-central New Mexico. Our results support earlier observations of asynchronous timing of migration between sexes of L. cinereus during spring, with females preceding males by ca. 1 month. We provide the first evidence that hoary bats may travel in dispersed groups, fly below the tree canopy along streams, and feed while migrating during spring. Analysis of guano revealed that diet of L. cinereus consisted mostly of moths, with more than one-half of samples identified as Noctuidae and Geometridae. We observed a late-spring decline in consumption of moths that might be related to seasonal changes in abundance of prey, differential selection of prey by bats, or sampling bias. We suspect that spring migration of L. cinereus through New Mexico temporally coincides with the seasonal abundance of moths.

We report characteristics of maternity roosts of Allen's lappet-browed bat (Idionycteris phyllotis) at the northernmost extent of its range. In summer 2004, three female I. phyllotis were fitted with radiotransmitters and followed to three roosts in cracks of the same cliff face within Grand Staircase-Escalante National Monument, Kane and Garfield counties, Utah. There were ≥15 bats in the three roosts, which were on a large northwest-facing cliff, in the eastern side of a small box-canyon. Piñon-juniper (Pinus-Juniperus) woodland was on ridge tops and bottoms of canyons, which were ca. 1,800 m elevation with mature to old-growth woodlands. Roosts were in the top one-half of the cliff face, which was tall and highly fractured, with a large talus slope at the base.

We measured prevalence of malaria infection and prevalence and intensity of chigger infection in Yarrow's spiny lizards (Sceloporus jarrovii) from three sites in the Chiricahua Mountains of southeastern Arizona. Our primary objective was to compare parasite load among sites, sexes, and reproductive classes. We also compared our findings to those of previous studies on malaria and chiggers in S. jarrovii from the same area. Of lizards examined, 85 and 93% were infected by malaria and chiggers, respectively. Prevalence of malaria was two times higher than previously reported for the same area, while prevalence of chiggers was similar to previous findings. Intensity of chigger infection was variable among sites, but not among reproductive classes. The site with the highest intensity of chigger infection also had the most vegetative cover, suggesting that this habitat was more favorable for non-parasitic adult chiggers.

Suitable nesting sites created as a result of construction of concrete bridges in southern Arkansas have allowed cliff swallows (Petrochelidon pyrrhonota) to extend their breeding range southward. During spring 2007, several locations in the Gulf Coastal Plain physiographic province of southern Arkansas were being used for nesting. These observations expand the known breeding range from the Red River drainage in southwestern Arkansas (and one location in the Ouachita River drainage) across the Gulf Coastal Plain including the Ouachita and Saline drainages of southeastern Arkansas.

In 2006, we observed two female Texas horned lizards (Phrynosoma cornutum) digging nests in hard caliche soil in Randall County, Texas. One female used her head in a twisting and side-to-side motion to backfill the nest, which may pack soil between eggs without injuring the eggs and prevent collapse of the nest during extreme precipitation. Hatchlings emerged from nests through single holes, which coincided with original entrances of tunnels that were excavated by females, and hatchlings had left the nest ≤24 h of when the first hatchling emerged. Behaviors during their first weeks above ground changed from an instant-flee response to a sudden-prolonged immobility within ca. 2 weeks. Hatchlings ate only ants <4 mm in length and avoided larger harvester ants (Pogonomyrmex rugosus). Hatchlings shed their skin ca. 4 weeks after emergence and began hibernation ca. 6 weeks later than adults.

Conventional attachment of radiotransmitters may not be feasible in pocket gophers due to their unique morphology and fossorial lifestyle. We implanted radiotransmitters subcutaneously in Ozark pocket gophers, Geomys bursarius ozarkensis, 3 March 2007–10 February 2008. Of the 72 surgeries, 70 were successful. We recaptured 22 individuals (range, 20–325 days post-implantation) and recorded a mean change in mass from implantation to recapture for adult males, adult females, and juveniles of 1.1% (SD  =  11.9), −1.6% (SD  =  9.0), and 17.3% (SD  =  18.8), respectively. We suggest that subcutaneous implantation is the best method for pocket gophers and may be applicable for other small mammals.

A well-preserved right lower jaw with complete P₃-M₁ and an isolated canine of a large felid was found in the southern state of Chiapas, Mexico. It is identified as the American lion Panthera leo atrox. Its presence in Chiapas documents its southernmost distribution in North America.

The cave myotis (Myotis velifer) is a colonial, cave-dwelling bat distributed from the southwestern United States to Honduras. I captured an adult, polydactylous female M. velifer at Fort Hood Army Installation, north-central Texas, on 26 July 2006. The bat had seven toes on her left foot and five toes on her right foot. The supernumerary toes appeared normally articulated and developed, and they were voluntarily controlled by the bat. I observed no other polydactylous M. velifer on Fort Hood. This is the second known occurrence of polydactyly in this species.

The Mexican long-tongued bat Choeronycteris mexicana is rare in Texas, as well as elsewhere in the United States and in Mexico. A C. mexicana was captured in December 2007 at a residence in El Paso, El Paso County, Texas. This is the first record of this species in western Texas.

Studies of distributional ecology of whiptail lizards near the Rio Grande in Presidio County, Texas, have resulted in discovery of Aspidoscelis neomexicana at three of >20 sites investigated. Records of A. neomexicana in Presidio County are >225 km southeast of sites inhabited by the species in El Paso, El Paso County. Observations made during 1988–2008 indicate that A. neomexicana in Presidio County inhabits only a few areas of floodplain where there is intermingling of several microhabitats characterized by loamy, gravelly alluvium with various combinations of trees, shrubs, Russian thistle (Salsola kali), Spanish dagger (Yucca torreyi), cacti, grasses, and forbs. Each species of whiptail lizard (i.e., A. exsanguis, A. tesselata, and A. tigris) that is syntopic with A. neomexicana is widely distributed in Presidio County and elsewhere in the United States and Mexico. Despite range maps to the contrary, A. neomexicana has not been recorded in Mexico; forays in 1993 to San Antonio, Chihuahua, across the Rio Grande ( = Río Bravo) from Candelaria, revealed only A. exsanguis and A. tesselata.