We examined diets of Western Burrowing Owls (Athene cunicularia hypugaea) based on contents of pellets and large prey remains collected year-round at burrows in each of the 3 regions in south central Nevada (Mojave Desert, Great Basin Desert, and Transition region). The most common prey items, based on percent frequency of occurrence, were crickets and grasshoppers, beetles, rodents, sun spiders, and scorpions. The most common vertebrate prey was kangaroo rats (Dipodomys spp.). True bugs (Hemiptera), scorpions, and western harvest mice (Reithrodontomys megalotis) occurred most frequently in pellets from the Great Basin Desert region. Kangaroo rats (Dipodomys spp.) and pocket mice (Perognathinae) were the most important vertebrate prey items in the Transition and Mojave Desert regions, respectively. Frequency of occurrence of any invertebrate prey was high (>80%) in samples year-round but dropped in winter samples, with scorpions and sun spiders exhibiting the steepest declines. Frequency of occurrence of any vertebrate prey peaked in spring samples, was intermediate for winter and summer samples, and was lowest in fall samples. With the possible exception of selecting for western harvest mice in the Great Basin Desert region, Western Burrowing Owls in our study appeared to be opportunistic foragers with a generalist feeding strategy.

The expansion of western juniper (Juniperus occidentals spp. occidentalis Hook.) in the northern Great Basin has resulted in the wide-scale conversion of sagebrush-steppe communities to juniper woodlands. Prescribed fire and mechanical cutting are the 2 main methods used to remove juniper and restore sagebrush steppe. Mechanical treatments commonly leave cut juniper on site. Disadvantages of leaving cut juniper are the increased fuel hazard and the potential for increased establishment and growth of invasive species. This study evaluated the response of herbaceous plants to winter burning of cut western juniper. Vegetation response was compared among 2 burning treatments (burning trees the first winter after cutting and burning the second winter after cutting), a control (cut-unburned juniper), and the interspace between cut trees. To minimize fire impacts to herbaceous perennials, cut trees were burned in the winter when soils and ground litter were frozen and/or soils were at field capacity. Only felled trees were burned, as fire did not carry into interspaces or litter mats around western juniper stumps. We hypothesized that winter season burning would increase herbaceous perennials and would reduce cheatgrass establishment when compared to the cut-unburned control. After 10 years, total herbaceous and perennial grass cover was 1.5- to 2-fold greater, respectively, in burned treatments compared to cut-unburned controls. Perennial grass density was 60% greater in the burned treatments than in the cut-unburned treatment and the interspace. Cheatgrass cover was twice as great in the control than in the 2 burn treatments and the interspace. We concluded that burning cut western juniper when soils were wet and frozen in winter enhanced community recovery of native perennials compared to leaving cut juniper unburned.

Because quantity and quality of roosting habitat can affect Merriam's Wild Turkey (Meleagns gallopavo merriami) distribution, we described habitat characteristics of Merriam's turkey roost sites in the southern Black Hills of South Dakota. Varying proportions of Merriam's turkeys in the southern Black Hills depended on supplemental feed from livestock operations during the 2 winters of our study, whereas the remainder wintered in forested habitat away from supplemental feed. We compared characteristics of roost habitat occupied by female turkeys from both groups. We located turkeys with radio-transmitters in the early morning and late evening to find roost sites. Female Merriam's turkeys in the southern Black Hills roosted exclusively in ponderosa pine trees, primarily on the upper portions of ridges on easterly aspects. Generally, trees >30 cm diameter at breast height (dbh) were chosen for roosting, but turkeys also roosted in trees with smaller dbh. During winter months, turkeys that relied on supplemental feeding roosted adjacent to the ranch-farmstead where the supplemental food was located. Generally, these turkeys used the same roost site(s) throughout the winter, whereas turkeys that remained in the forest during winter used multiple roost sites. We suggest maintaining stands of trees >30 cm dbh on the upper portions of easterly aspects to provide suitable roosting habitat for female Merriam's Wild Turkeys in the southern Black Hills.

Bluehead sucker (Catostomus discobolus) and flannelmouth sucker (Catostomus latipinnis) populations are declining throughout these species' native ranges in the Upper Colorado River Basin. In order to conserve these populations, an understanding of population dynamics is needed. Using age estimates from pectoral fin rays, we describe age and growth of these 2 species in 3 Wyoming stream systems: Muddy Creek, the Little Sandy River, and the Big Sandy River. Within all 3 stream systems, flannelmouth suckers were longer-lived than bluehead suckers, with maximum estimated ages of 16 years in Muddy Creek, 18 years in Little Sandy Creek, and 26 years in the Big Sandy River. Bluehead suckers had maximum estimated ages of 8 years in Muddy Creek, 10 years in Little Sandy Creek, and 18 years in the Big Sandy River. These maximum estimated ages were substantially greater than in other systems where scales have been used to estimate ages. Mean lengths at estimated ages were greater for flannelmouth suckers than for bluehead suckers in all 3 streams and generally less than values published from other systems where scales were used to estimate ages. Our observations of long life spans and slow growth rates among bluehead suckers and flannelmouth suckers were probably associated with our use of fin rays to estimate ages as well as the populations being in headwater tributaries near the northern edges of these species' ranges.

Seventeen mixed conifer stands infested with knobcone pine dwarf mistletoe (Arceuthobium siskiyouense) were sampled to evaluate host susceptibility to this parasitic plant. Temporary circular plots (radius 6 m) were established around dominant, severely infected knobcone pines (Pinus attenuata). Within plots, species, diameter at breast height, and dwarf mistletoe rating (6-class system) were determined for each live tree taller than 1.4 m. More than 2000 trees were sampled in 140 plots. Based on the incidence of infection, tree species were assigned to host-susceptibility classes. Although Jeffrey pine (Pinus jeffreyi) and shore pine (Pinus contorta var. contorta) have been classified as rare hosts of knobcone pine dwarf mistletoe, my results suggest that Jeffrey pine should be classified as a principal host and shore pine should be classified as an occasional host. No infection was observed on western white pine (Pinus monticola), Douglas-fir (Pseudotsuga menziesii), or incense-cedar (Calocedrus decurrens), indicating that these species should be classified as immune.

Multiple surveys carried out by herpetologists in México, D.F., during the 1980s failed to find specimens of Aspidoscelis septemvitatta (Squamata: Teiidae). However, 10 specimens were recently collected to the east of México, D.F., inside a protected area, Sierra de Santa Catarina. The Sierra de Santa Catarina has been heavily modified by human activity and habitation. Morphological and natural history information about the specimens are presented, as well as notes on locality.

Inland populations of cutthroat trout have suffered dramatic declines and some subspecies are considered threatened or endangered. Understanding patterns of variation and factors that influence life history in populations is important for conservation and management. We determined effects of elevation, sex, and genetic introgression (with Yellowstone cutthroat trout, Oncorhynchus clarkii lewisi, and rainbow trout, Oncorhynchus mykiss) on growth rates of Colorado River cutthroat trout (Oncorhynchus clarkii pleuriticus) in the Sheep Creek drainage in the Uinta Mountains of Utah. In this high-elevation system, native trout grew slowly and matured relatively late. Elevation, sex, and genetic introgression all had significant effects on growth rates. Growth rates were lower at higher elevations. Males were slightly larger than females, and cutthroat trout in locations that were more introgressed grew faster than those at nonintrogressed locations. Both abiotic effects and effects of introduced salmonids must be addressed in long-term management programs to ensure the sustainability of native trout populations.

Two molecular marker systems, random amplified polymorphic DNA (RAPD) and microsatellites, were used to evaluate population diversity and differentiation in 4 northern Nevada Bromus tectorum populations. From 80 RAPD primers, we found 16 (20%) that yielded 165 strong repeatable bands. Of those bands, 60 (35.8%) were polymorphic. Of those, 21 met data-pruning guidelines for final analysis. RAPD variation was moderate ( = 0.363, S = 0.022), ranging from 0.312 to 0.404. Microsatellite variation was similar ( = 0.234, S = 0.051) but varied more widely, ranging from 0.009 to 0.551. All populations were out of Hardy-Weinberg equilibrium, as expected in a predominantly selfing species. RAPDs revealed significant differentiation (P < 0.0001) across populations, whereas microsatellites only resolved 2 of the 4 populations. RAPDs revealed a considerable amount of variation in the 2 populations, Hot Springs and Truckee, which had nearly identical microsatellite profiles. Of 184 individuals, we found 182 unique RAPD phenotypes. We found 51 microsatellite genotypes across individuals, one of which was present in 95.3% of the individuals in the Hot Springs-Truckee group and 29% of the Stillwater individuals. The UPGMA phenograms were similar in grouping Hot Springs with Truckee, and Stillwater with Peavine, and were highly correlated but not significantly. Both marker systems proved useful in assessing population genetic variation. One population-specific RAPD marker and 6 new microsatellite-length polymorphisms were identified. Both marker systems may also prove useful in studying other closely related species such as red brome (Bromus nibens).

Ponderosa pine Pinus ponderosa and Douglas-fir Pseudotsuga menziesii forests in the Interior of British Columbia, Canada, are adjacent to grasslands. Forest ingrowth and tree encroachment, mainly due to fire suppression, represent threats to both forest and ranching industries in the region. The use of prescribed burning for ecological restoration is being practiced, but the associated ecosystem effects of restoration treatments have been little studied in the region. We used a randomized complete block design in a prescribed burning experiment. Tree survival and the responses of understory vegetation to burning were monitored for 3 years. The transect method along with crown projection areas (onto the ground) were used in comparisons between areas inside and outside of the burned area. Fire was effective in eliminating small ponderosa pine (dbh < 10 cm) and Douglas-fir (dbh < 20 cm) trees. Therefore, the objective of controlling the encroachment of trees was met by the prescribed burn. Species composition at both sites was modified by prescribed burning, but spatial variability was overridden by treatment and temporal effects. Immediate, short-term reduction of big sagebrush Artemisia tridentata ssp. wyomingensis was observed in grassland sites, while reduction in rabbitbrush Chrysothamnus nauseosus in the forest was observed. Data trends indicate that 3 years after burning, total biomass and forb biomass increased in grasslands, but graminoid biomass in forests was reduced and total understory biomass was not affected by burning. Burning also reduced the shrub component in these ecosystems. While aboveground biomass production may be enhanced by burning in grasslands, the impact of burning on forest understory was minimal and burning may result in reduction of graminoids. Therefore, burning can be used to control tree encroachment and forest ingrowth in this region. Management plans must incorporate topography, species diversity, and tree survival to target areas that are most susceptible to tree encroachment and to achieve desired results. Extended monitoring is necessary to determine the long-term effects of burning on species diversity in and productivity of these ecosystems.

Cheatgrass (Bromus tectorum) is an invasive annual known to negatively impact many shrub-dependent organisms; however, relatively little research has examined how it affects snake communities. Bromus tectorum is abundant at Antelope Island State Park, Davis County, Utah, and could be a possible threat to snake populations. Study sites representing different B. tectorum coverage percentages were established to measure relative abundance of snakes. Snakes were captured from June to September 2005 primarily by using funnel traps attached to drift-fence arrays. Linear regression revealed a negative relationship between B. tectontm coverage (%) and the relative abundance of the Great Basin gopher snake (Pituophis catenifer deserticola) and the western racer (Coluber mormon). These results (1) suggest that B. tectorum invasions result in reduced snake abundance in shrubsteppe habitat on Antelope Island and (2) add to our understanding of the relationships between B. tectorum and native fauna.