This study was completed to better understand pronghorn antelope (Antilocapra americana) populations found throughout Idaho. Antelope were studied in three separate and distinct study areas. The Big Desert, Camas Prairie, and Little Lost and Pahsimeroi valleys were all selected as study sites. Idaho Department of Fish and Game (IDFG) is concerned with current pronghorn populations found throughout Idaho. Pronghorn are a valued big game species found in Idaho. Increasing pronghorn populations in Idaho is a focus of IDFG. We captured and VHF-collared pronghorn fawns found in our three study areas. Fawns were monitored daily with telemetry equipment for survival. Field necropsies were performed to determine cause of death for each fawn. We found that fawns across Idaho had acceptable survival rates compared to previous studies conducted on pronghorn. The highest cause of mortality on fawns was coyotes (Canis latrans). Other predators on pronghorn fawns were bobcats (Lynx rufus), golden eagles (Aquila chrysaetos), and black bear (Ursus americanus). We found that fawns radio-collared with a higher BMI (body mass index) were more likely to survive. We examined other relationships that could have an effect on fawn survival. Rabbits (Lepus californicus, Lepus townsendii Sylvilagus nuttallii, Brachylagus idahoensis, Lepus americanu) and ground squirrels (Urocitellus armatus, Urocitellus mollis, Urocitellus elegans, Urocitellus columbianus) were examined to see if there population numbers had an effect on pronghorn fawn survival. We found a relationship between rabbit density and fawn survival, as rabbit density increased pronghorn fawn survival increased. Ground squirrel density was found to have no effect. Coyote density was studied to see if coyote density effected pronghorn survival. No relationship was found between coyote density and pronghorn fawn survival. Habitat quality can impact animal populations. We examined habitat variables that could affect pronghorn fawn survival. NDVI (normalized difference vegetation index) was examined and we found no correlation in this study. Pronghorn fecal samples were collected and analyzed at a laboratory to look for diet quality correlation to pronghorn survival. We found a correlation between diet quality (DAPA) and pronghorn fawn survival. Diet quality can be linked to habitat quality, as habitat quality increases so does pronghorn fawn survival. Habitat quality, rabbits, and a fawn’s BMI all were linked to increased fawn survival. We recommend wildlife managers create and increase pronghorn habitat when possible to produce better pronghorn fawn survival.

Thesis (Ph. D.)--University of Wyoming, 2007. / Title from PDF title page (viewed on Jan. 9, 2009). Includes bibliographical references.

abstract: For the past 30 years wildlife biologists have debated the need of pronghorn antelope (Antilocapra americana) to drink freestanding water (free water). Some have suggested that pronghorn may feed at night to increase preformed water (plant moisture) intake, thus decreasing their dependence on free water. Pronghorn diet composition and nutrient intake is integral to understanding water available to pronghorn through preformed and metabolic sources. The dual purpose of this study was to determine plant composition of pronghorn diets, and to examine whether night feeding provides a water allocation advantage by testing for differences between day and night and modeling free water requirements during biologically critical seasons and years of different precipitation. I determined species composition, selected nutrients, and moisture content of American pronghorn diets on Perry Mesa, Arizona in March, May, June and August of 2008 and 2009. I used microhistological analysis of fecal samples to determine percent plant composition of pronghorn diets. I used forage samples to evaluate the nutrient composition of those diets for moisture, crude protein and structural carbohydrates, and to calculate metabolic water. I used calculations proposed by Fox et al. (2000) to model free water requirements and modified the equations to reflect increased requirements for lactation. Diet analysis revealed that pronghorn used between 67% and 99% forbs and suggested fair range conditions. Preformed water was not significantly different between night and day. Night feeding appeared to be of marginal advantage, providing an average potential 9% preformed water increase in 2008, and 3% in 2009. The model indicated that neither male nor female pronghorn could meet their water requirements from preformed and metabolic water during any time period, season or year. The average free water requirements for females ranged from 0.67 L/animal/day (SE 0.06) in March, 2008 to 3.12 L/animal/day (SE 0.02) in June, 2009. The model showed that American pronghorn on Perry Mesa require access to free water during biological stress periods. / Dissertation/Thesis / M.S. Applied Biological Sciences 2012

abstract: Grassland habitat restoration activities are occurring within the semi-arid grasslands of the Agua Fria National Monument located 65 km north of Phoenix, AZ. The goal of these restoration activities is to reduce woody species encroachment, remove lignified plant materials and recycle nutrients within the ecosystem thus improving range conditions for both wildlife species and livestock. Broadcast burning, juniper thinning and slash pile burns are the principle tools used to accomplish resource objectives. Line cover, belt transect, densities, heights and biomass of vegetation data were collected to determine the response of the vegetative community to habitat restoration activities. Principal Component Analysis (PCA) was used to reduce data analysis to the more influential factors. Regression analysis was conducted for statistically significant response variables. Quadratic regression analysis found low predictive values. In broadcast burn treatment units, all important factors as identified by PCA had low predictive factors but significantly differed (R2 <0.01, p<0.05) between unburned and the years post treatment. Regression analysis found significant, albeit weak, relationships between time since treatment and independent variables. In pile burn treatment units, data reduction by PCA was not possible in a biologically meaningful way due to the high variability within treatment units. This suggests the effect of juniper encroachment on grassland vegetation persists long after junipers have been cut and burned. This study concluded that broadcast burning of the central Arizona grasslands does significantly alter many components of the vegetative community. Fuels treatments generally initially reduced both perennial woody species and grasses in number and height for two year post fire. However, palatable shrubs, in particular shrubby buckwheat, were not significantly different in broadcast burn treatment areas. The vegetative community characteristics of juniper encroached woodlands of central Arizona are unaffected by the removal and burning of junipers aside from the removal of hiding cover for predators for multiple years. It is recommended that habitat restoration activities continue provided the needs of wildlife are considered, especially pronghorn, with the incorporation of state and transition models specific to each of the respective ecological site descriptions and with the consideration of the effects of fire to pronghorn fawning habitat. / Dissertation/Thesis / M.S. Applied Biological Sciences 2014

Free water can be a limiting factor to wildlife in arid regions of the world. In the western United States, management agencies have installed numerous, expensive wildlife water developments (e.g. catchments, guzzlers, wells) to: 1) increase the distribution or density of target species, 2) influence animal movements, and 3) mitigate for the loss of available free water. Despite over 50 years as an active management practice, water developments have become controversial for several species. We lack an integrated understanding of the ways free water influences animal populations. In particular, we have not meshed understanding of evolutionary adaptations that reduce the need for free water and behavioral constraints that may limit use of otherwise available free water with management practices. I propose a conceptual framework for understanding more generally how, when, and where wildlife water developments are likely to benefit wildlife species. I argue that the following five elements are fundamental to an integrated understanding: 1) consideration of the variable nature in time and space of available free water, 2) location and availability of pre-formed and/or metabolic water, 3) seasonal temperature and precipitation patterns that influence the physiological need for water, 4) behavioral constraints that limit use of otherwise available free water, and 5) proper spacing of water sources for target species. I developed this framework from work done primarily with chukars (Alectoris chukar). I also report supporting evidence from research with mule deer (Odocoileus hemionus). Chukars demonstrated a spatial response to available free water when estimates of dietary moisture content were < 40%. Mule deer photo counts were reduced at water sources with small-perimeter fencing, suggesting increased predation risk caused mule deer to behaviorally avoid use of otherwise available free water. When all five framework elements are considered, I found strong evidence that wildlife water developments have benefited some chukar populations. Historic chukar counts suggested a population benefit following installation of wildlife water developments. Experimental removal of access to free water caused increased movements and decreased survival of adult chukars.

I studied the relationship between coyote (Canis latrans) removal and pronghorn (Antilocapra americana) and mule deer (Odocoileus hemionus) density and fawn:doe ratios in southwest Wyoming and northeast Utah in 2007 and 2008. Coyote removal variables studied included the number of coyotes removed, ground hours worked, total hours worked, coyotes removed/aerial gunning hour, coyotes removed/ground work hour, and coyotes removed/total effort hour. None of the variables explained changes observed in fawn:doe ratios of pronghorn or mule deer. The number of coyotes removed, ground hours worked, total hours worked, and coyotes removed/aerial gunning hour were positively correlated with pronghorn density. However, none of the coyote removal variables were correlated with mule deer density. Coyote removal conducted in the winter and spring explained more variation and had a stronger positive correlation with fawn survival and ungulate density than removal conducted in the summer or fall. My results suggest that coyote removal conducted over large areas may increase density of pronghorn. However, coyote removal did not appear to increase mule deer fawn survival or density.

In a territorial population of pronghorn from Antelope Island, UT, interaction between male dominance and territory defense was examined. High-ranking males were more likely to defend territories. Closely ranked animals engaged in more dominance interactions than distantly ranked individuals, and middle-ranked animals were involved in disproportionately more interactions than either high- or low-ranking animals. Large males possessed large horns and prongs as well as small cheek patches. Results from a factor analysis suggested that large males defended territories with a high density of sage. However, in this study, we did not observe pronghorn feed on sage during the territorial season. Though male pronghorn practiced resource defense polygyny, large, dominant males did not defend territories with a high density of green vegetation or green forbs. Large males appeared to defend territories with low visibility. In 1996, intruders entered areas that contained females throughout the territorial season. During the next year, highly visible, small territories received the most intrusions. Together, these observations suggest defense of tactical locations. Defending a tactical location may help females avoid harassment and males hide the presence of females. Different populations of pronghorn practice different mating systems. To understand this variation, we examined the behavior patterns/rates of individual territorial and bachelor males. The highest rates of activity and behavior patterns occurred in March/April and in September. Territorial males cheek rubbed at a higher rate than bachelors. Territorial males were more active and SPUD (sniff, paw, urinate, and defecate) marked at a higher rate than bachelor males in 1996. After the formation of a bachelor herd in 1997, bachelor males showed higher rates of male-male interactions than territorial males. Territorial males maintained the same activity and behavioral rates in the presence and absence of females. Dispersion pattern of scent marks was more clumped in the presence of females. These findings suggest cheek rubs function more as a space-claiming behavior while SPUD marking is more strongly associated with male-male interactions. Comparison to male behavior in nonterritorial populations indicates that the behavioral mechanisms are present in all populations to accommodate shifts in social systems.

Feral horses occupy 31.6 million acres throughout western North America. Feral horses share similar habitats with a wide range of animal species, including pronghorn. Since horses are larger and often more aggressive than other animals of this region, they are generally socially dominant over all other native ungulate species. Pronghorn share water sources with horses in areas where both occur. In situations where horses exclude pronghorn from water, pronghorn fitness may be impaired, especially during the hottest months of the year when water is limited. The purpose of this study was to investigate interference competition between pronghorn and feral horses at water sources. During spring and summer 2010-11, we placed motion-sensitive cameras at water sources across the Sheldon National Wildlife Refuge in northwest Nevada. Cameras were used to examine the overlap of water use by pronghorn and horses and to determine the occurrence of spatial or temporal partitioning of water between these species. Additionally, we made direct observations of horses and pronghorn at high-use water sources to record the occurrences and outcomes of pronghorn/horse interactions as well as differences in pronghorn behavior in the presence and absence of horses. Pronghorn spent more time on vigilance behavior and less time foraging or drinking in the presence of horses than in their absence. Nearly half of pronghorn/horse interactions at water resulted in pronghorn exclusion from water. Our data also suggest that temporal partitioning of water between horses and pronghorn on an hourly basis may be occurring.

Water is a vital resource for species inhabiting arid and semi-arid regions and can shape the biotic communities that we observe. Because water is considered a limiting resource for many species in desert environments, there is the potential for competitive interactions between species to occur at or around water sources. For this dissertation I tested hypotheses related to resource competition among different species of wildlife in the Great Basin and Mojave Deserts of western Utah. Chapter one evaluated the influence of feral horses (Equus caballus) on patterns of water use by communities of native birds and mammals. Chapter two determined if feral horses competed with pronghorn (Antilocapra americana) and mule deer (Odocoileus hemionus) for access to water. In chapters one and two, we found evidence that horses compete with native wildlife for water. In chapter one, horses were associated with decreased richness and diversity of native species at water sources. Native species also had fewer visits and spent less time at water sources frequented by horses. In chapter two, we found that pronghorn and mule deer used water sources less often where horse activity was high. There were also significant differences in temporal activity for pronghorn, but not mule deer, at horse-occupied sites versus sites where horses were absent or uncommon. Our results indicated that horses spatially and temporally displaced other species at water sources providing evidence of a negative influence on how communities of native wildlife access a limited resource in an arid environment. Chapter three assessed whether dominant carnivores (coyote (Canis latrans) and bobcat (Lynx rufus)) negatively influenced the spatial use of water sources by the subordinate kit fox (Vulpes macrotis). Our results did not reveal strong negative associations between kit fox visits to water sources and visits by dominant carnivores; in fact, dominant carnivores contributed very little to the use of water by kit foxes. Instead, kit fox visits were more closely associated with habitat features at water sources. Our findings indicate that dominant carnivores are not the primary driver of use of water sources by subordinate carnivores. Chapter four evaluated whether a simulated loss of water due to climate change/increased human use would differentially affect desert bats based on flight morphology and maneuverability. When we experimentally reduced surface area of water sources, larger, less-maneuverable bats experienced a 69% decrease in drinking success and increased competition with smaller, maneuverable bats. Anticipated reductions in the sizes of water sources due to climate change may lead to species with less maneuverability being unable to access water efficiently and facing increased competition from more agile bats.