Human-made or -modified water sources (i.e., catchments) are widely used for wildlife management in the arid western United States, where thousands of such catchments have been built to enhance wildlife populations and mitigate for the loss of natural water sources. For decades, the need for and value of catchments to wildlife was unquestioned. Recently, however, the use of catchments has become controversial, particularly on public lands. Impacts to wildlife populations and wildlife habitats have been central to the debate, which has, in large part, been fueled by a paucity of scientific information. Value-based conflicts over management practices on public lands also have played a significant role.

Desert ungulates must contend with high solar radiation, high ambient temperatures, a lack of water and cover, unpredictable food resources, and the challenges these factors present for thermoregulation and water balance. To deal with the conflicting challenges of maintaining body temperature within acceptable limits and minimizing water loss, desert ungulates use a variety of physiological, morphological, and behavioral mechanisms. The mechanisms involved in thermoregulation and water balance have been studied in many domestic and wild African and Middle Eastern ungulates; studies involving ungulates inhabiting North American deserts are limited in comparison. Our objectives were to review available scientific literature on thermoregulation, water balance, and the effects of dehydration in desert ungulates. We discuss the physiological, morphological, and behavioral mechanisms used by ungulates to maintain temperature and water balance in arid environments, and the implications for research and management of desert ungulates in western North America.

Construction of water developments has been used as a wildlife-habitat improvement technique in desert environments since the 1940s. Use of water developments by wildlife has been described in anecdotal observations, through water-hole counts, and with triggered still-cameras, but few studies have directly quantified wildlife use. We used video surveillance equipment to document wildlife use of 3 water catchments located in the Sonoran Desert, southwestern Arizona, USA, from June 2000 to November 2003. For each visitation, we recorded time of day, season of use, and activities engaged in, and we correlated visits with temperature and relative humidity. We logged 37,989 observation hours and documented 34 species using the water catchments. Most of the species recorded visited water catchments year-round with use peaking during June and July. The number of visits by nongame species (i.e., bats, raptors, mammalian predators, and rodents) exceeded the number of visits by game species (mule deer [Odocoileus hemionus], doves [Zenaida spp.], and Gambel's quail [Callipepla gambelii]). Visitation frequency for turkey vultures (Cathartes aura), owls, diurnal raptors, mule deer, coyotes (Canis latrans), and other mammalian predators increased with temperature. Most visits culminated in the animal drinking water. Other activities recorded were bathing, consumption of plant material and carrion, and intraspecies and interspecies interactions. We recorded 8 predation attempts: 4 by avian predators and 4 by bobcats (Lynx rufus). Although we documented that a number of species frequented water catchments, our observations do not prove need. However, we believe our observations do provide support for constructing water catchments that can accommodate a wide diversity of species.

Anecdotal evidence suggests that desert water developments attract birds; however, few studies have focused on the role of surface water in habitat selection by migratory birds. Therefore, we studied bird use of wildlife water developments in the Sonoran Desert of southwestern Arizona, USA, using 2 observational approaches (bird surveys in washes with and without water developments and direct observations at water developments) and 1 experimental approach (direct observations at water sources with and without vegetation cover). In spring 2004, we conducted weekly bird surveys at 3 pairs (with and without water developments) of washes. In spring 2005, we designed an experiment to test whether migratory birds more frequently used water developments with than without vegetation cover. During spring, in both 2004 and 2005, we documented use of water by directly observing birds at 13 existing water developments. We found little evidence to support that water developments were important water sources for migratory birds. Migratory bird communities in desert washes near wildlife water developments did not differ in species richness, relative abundance, or density when compared with washes without water developments. This observation suggests that the wildlife water developments that we studied were not an attractant to migratory birds at the landscape scale. At a finer scale, migratory birds rarely (0.1% of all observations) used water developments and experimental water sources. However, resident bird species frequently were recorded (>69,000 observations) drinking and bathing at wildlife water developments. Based on our observations, we conclude that water developments are an important resource for local bird populations in the Sonoran Desert, USA, particularly during periods of drought.

In the southwestern United States, livestock water troughs may be the only water source available to bats during dry seasons or periods of drought. We found that 38% of the 90 livestock water troughs we surveyed in northern Arizona, USA, were modified with either fencing to separate pastures or braces to strengthen the structures. We tested if these modifications could affect bat drinking behavior or increase injury risk by simultaneously videotaping modified and unmodified troughs in a series of crossover experiments performed between 1 March and 26 August 2004. The bats that we observed did not avoid modified troughs but required 3–6 times the number of passes to approach the water surface at both troughs with fences and those with support braces. The number of passes required to drink increased with reduced water surface area, suggesting that modifications of smaller troughs may have a greater effect. Small (e.g., Myotis spp.) and large (e.g., pallid bat [Antrozous pallidus]) bats responded similarly in the experiments. These effects may be energetically expensive for bats, especially during periods of high energy demands, such as pregnancy and lactation. Although we did not document any injuries or mortalities, 16 bats contacted wires at modified troughs with smaller surface area. This suggests that modifications of smaller troughs may pose higher risks of injury. To reduce these risks, we recommend removing modifications on water troughs whenever feasible.

We studied habitat use by desert mule deer (Odocoileus hemionus eremicus) in the Sonoran Desert to understand the relative importance of vegetation, terrain characteristics, human disturbances, and water sources in determining their distribution. We located 44 radiocollared female mule deer weekly over 5 years. In spring, when water was most scarce, deer were in areas with lower elevations, shallower slopes, and greater normalized difference vegetation index (NDVI) rates, when compared to random locations. Use of water developments (i.e., catchments) during spring was evident but their effect on deer distribution was small relative to other factors, and their importance varied by animal. More deer locations were recorded in areas of higher NDVI rate in spring, summer, and autumn, but they were also further from washes in autumn. The deer we monitored used lower elevations in spring and higher elevations during the rest of the year. The effect of slope was strong in all seasons. However, deer tended to select shallow slopes in spring and steep slopes during the rest of the year. Deer avoided roads in summer and autumn but were closer to them in winter. They avoided rivers or canals in summer but were closer to those features in autumn. Our results suggest that terrain characteristics in all seasons (slope and elevation), as well as forage quality in 3 of 4 seasons (as indexed by NDVI rate) were most important in determining distribution of deer. Concomitantly water catchments had a measurable, but minor, role during hot, dry conditions. We recommend investigators continue to evaluate the importance of water developments relative to other habitat factors, particularly via the use of multivariate studies, global positioning system technology, adaptive management, and temporary closure of water developments known to be used by radiocollared deer.

The addition of wildlife water developments (i.e., catchments) to arid areas may concentrate foraging by desert ungulates and decrease forage availability near catchments. We looked for gradients in forage biomass and use by mule deer (Odocoileus hemionus) and bighorn sheep (Ovis canadensis) along dry riparian streams near catchments. We measured forage biomass and pellet group density in transects following vegetation along edges of desert washes near catchments and in control washes with catchments >3 km away. Ungulate use, as reflected by pellet group density, was greatest in washes with catchments in place >3 years. There was some evidence for a gradient in pellet density in spring (slope = −0.012, P = 0.088) and summer (slope = −0.013, P = 0.015), and for differences between catchment and control transects in all seasons (13–46 pellet groups/ha, P ≤ 0.077). We found no evidence of an effect of catchments on forage biomass in nearby washes: we detected no gradient in forage biomass nor an overall difference between washes with catchments and those without (P > 0.15). Desert ungulates used washes near catchments in our study area but had minimal effects on nearby vegetation.

We compared water quality at natural tinajas and 2 types of wildlife water developments in the deserts of southeastern California, USA. We analyzed water samples collected from each site for pH, conductivity, alkalinity, aluminum, ammonium, arsenic, cadmium, calcium (Ca), chloride, chromium, copper (Cu), iron, lead (Pb), manganese, magnesium (Mg), mercury, nickel, nitrate, organophosphate, potassium, silica, silver, sodium, sulfate, and zinc (Zn). With few exceptions, values for pH were within standards established for livestock drinking water. The levels of Ca, Cu, Pb, Mg, silica, and Zn differed by type of water source. We believe those differences are related to construction materials, design, or substrate. With the exception of pH, none of the analytes tested for exceeded standards recommended for livestock drinking water. We conclude that the quality of water available at man-made water sources in southeastern California desert environments does not constitute a wildlife health threat.

Thousands of wildlife water developments, commonly known as gallinaceous guzzlers or guzzlers, have been installed throughout the western United States. In general, these units collect runoff from a concrete or other impervious surface and store that water in underground tanks. Water availability is limited to wildlife able to enter a small opening (approx. 20 cm in height) and crawl or walk down a sloped surface to the level of stored water. This design precludes use by large mammals. Moreover, wildlife occasionally may become entrapped in storage tanks, potentially fouling stored water. We developed a method of modifying gallinaceous guzzlers that allows large animals to access stored water and simultaneously decreases the probability of wildlife becoming entrapped in those guzzlers.

The Grand Staircase-Escalante National Monument (GSENM) was established by Presidential Proclamation in 1996. The GSENM management plan identified determining the status of natural water sources and their ability to support wildlife species as a priority. The arid, rugged terrain of the GSENM limited the utility of conducting ground surveys to accomplish this task. Given the technological advancements in remote sensing (RS), monument managers were interested in learning if this new technology could be used to quantify natural water sources. We conducted this study to determine if satellite imagery and predictive Geographic Information Systems (GIS) models could accomplish this task. To conduct this research, we established training sites at known GSENM natural water sources. We used these training sites to identify areas on satellite imagery that exhibited similar spectral characteristics. These sites were subsequently ground-truthed. We found water sources at only 3 of 36 sites predicted (8% efficiency). Limitations of the RS/GIS techniques employed in this study included imagery resolution, water-source size, and geographic shadowing.

In recent times the construction and maintenance of wildlife water developments for the stated purpose of conserving desert bighorn sheep (Ovis canadensis) populations has been controversial, especially within sensitive lands of the southwestern United States. A major portion of the controversy is whether wildlife water developments provide a benefit to populations of desert bighorn sheep and whether the associated incursion into the naturalness of an area is justified. Desert bighorn sheep are a valued natural resource and they exist today in small, isolated populations threatened with a variety of human-related impacts (e.g., disease, development, climate change, habitat fragmentation, water diversion). In this article I summarize the available published literature related to desert bighorn sheep and wildlife water developments and review the effects and consequences of water developments in desert bighorn sheep conservation. Based on my review, I contend that recent criticism of water developments has failed to adequately consider anthropogenic factors that can influence wildlife populations and their habitats. My review found that desert bighorn sheep benefit from water developments and that the role of active management of wildlife habitat, including the development of free-standing water for bighorn sheep where this component is unavailable, is justified as a means of mitigating negative anthropogenic influences in an otherwise natural setting.

Minnesota waterfowl management plans prescribe widespread deployment of mallard (Anas platyrhynchos) nest structures. We compared 53 single- and 57 double-cylinder nest structures from 1996 to 2003 because managers used both structure types but were uncertain about their respective cost-effectiveness. More nests occurred in double-cylinder structures, but numbers of successful nests and hatched ducklings were comparable for both types. Nest success in single- and double-cylinder structures was 92.8% and 79.4%, respectively, with nest abandonment being >4.5 times greater in doubles. Structure damage occurred only at ice-out and was greater for doubles. However, relative risk of failure for double- versus single-cylinder structures was similar (1.26; 95% CI = 0.91–1.75) and increased with size of the open-water area containing the structure. Modeling indicated approximately 95% of recruits from nest structures were additional recruits. A case-history approach indicated doubles produced an additional recruit for $23.11 versus $23.25 for singles. However, these estimates were sensitive to assumptions used to apportion costs between structure types and ignored structure-placement influences. Placement affected cost-effectiveness significantly, with structures placed in open-water areas >10 ha being more cost-effective. Results also suggested singles might be more effective than doubles when placement is considered. Lower nest abandonment alone might make single-cylinder structures the better choice.

Radiotransmitters are widely used in wildlife ecology, often providing data that cannot be collected using other methods. However, negative effects have been associated with the use of transmitters for some species. We evaluated the effects and performance of 4 radiotransmitter types for use with surf and white-winged scoters (Melanitta perspicillata and M. fusca): COEXT—coelomically implanted transmitters with external antennas, COINT—coelomically implanted transmitters with internal antennas, SUBCU—subcutaneous implants with external antennas, and PRONG—external mounts, attached by a subcutaneous anchor and glue, with external antennas. Survival was not related to radiotransmitter type during the immediate (14-d) post-release period when most deaths (8 of 12) occurred. Rates of signal disappearance (transmitters ceased to be detected in the study area) and transmitter shedding (transmitters recovered without sign of predation) were similar among types over 30- and 60-day intervals; however, higher proportions of dorsally mounted radiotransmitters (SUBCU, PRONG) disappeared or were shed over course of the full 100-day monitoring period used in this study. All 4 radiotransmitter types allowed for relatively accurate location estimates, with linear error estimates (distance between actual and estimated location) averaging <50 m when receivers were within 1 km of transmitters. However, signal strength was lower for COINT transmitters. Based on our results, we recommend COEXT transmitters for radiotelemetry studies >2 months in duration and for satellite telemetry studies of scoters. However, SUBCU and PRONG are recommended as cost-effective alternatives in shorter-duration radiotelemetry studies.

We examined diets of lesser scaup (Aythya affinis) and greater scaup (A. marila) during autumn 1999 and spring 2000 at 3 major stopover sites on lakes Erie, Ontario, and St. Clair in southern Ontario, Canada. Overall dietary composition did not differ between sexes in lesser or greater scaup. We also did not detect interspecific or sex-related differences in average size of zebra mussels (Dreissena polymorpha) consumed by scaup, but both species ate slightly larger zebra mussels during spring, as compared with autumn. Dietary intake of lesser scaup differed between seasons and among stopover sites. Lesser scaup generally ate more zebra mussels during spring and more gastropods and plants during autumn. Lesser scaup at Lake Ontario, Lake Erie, and Lake St. Clair, respectively, consumed more zebra mussels, nonmollusk animal matter (crustaceans and insects), and plant matter than did conspecifics at the other 2 locations. Greater scaup diets differed depending on both season and stopover site. At Lake Ontario greater scaup diets contained more zebra mussels but fewer gastropods during spring as compared with autumn, but there were no seasonal differences in consumption of those 2 food items at Lake Erie. Greater scaup at both Lake Ontario and Lake Erie did not show seasonal differences in consumption of plant matter, but autumn-staging birds at Lake Erie contained more plant matter than did autumn-staging birds at Lake Ontario. Interspecific comparisons of dietary intake of scaup staging at lakes Erie and Ontario showed that greater scaup generally ate more gastropods and plant matter than did lesser scaup, whereas lesser scaup consumed more zebra mussels than did greater scaup. Overall, our study showed that zebra mussels, gastropods, and submerged aquatic plants all currently are important foods during both autumn and spring for lesser and greater scaup staging on the lower Great Lakes (LGL). Consumption of zebra mussels by scaup is of particular concern because of the hypothesized link between scaup foraging ecology, zebra mussels, and elevated selenium burdens documented recently in scaup staging on the LGL. Thus, our findings that both scaup species generally ate more and larger zebra mussels during spring illustrates the need for further investigation into contaminant acquisition and burdens in wintering, staging, and breeding scaup, particularly those using, or originating from, the LGL region.

Juvenile survival has been identified as the most critical demographic parameter influencing grouse populations. Little information currently exists on survival of juvenile lesser prairie-chickens (Tympanuchus pallidicinctus). We regularly flushed 51 individually identifiable lesser prairie-chicken broods over a 6-year period to estimate survival from hatch to 14 days post-hatch (early period) and from 15 to 60 days post-hatch (late period). Estimates of overall daily survival rates were 0.949 (95% CI = 0.932–0.966) for the early period and 0.978 (95% CI = 0.968–0.989) for the late period. Overall survival from hatch to 60 days posthatch was 0.177 (95% CI = 0.028–0.376). We used encounter histories of 31 transmitter-equipped juveniles to estimate survival from 1 August to 31 March (overwinter) using known-fate models. Juvenile overwinter survival was 0.70 (95% CI = 0.47–0.86), and chicks heavier than average for their age at 50–60 days posthatch were more likely to survive the 8-month overwinter period. Survival of juveniles from hatch to 31 March of the following year was 0.12 (95% CI = 0.01–0.32). We compared overwinter survival of juveniles and 93 transmitter-equipped full-grown lesser prairie-chickens using a second set of models. Overwinter survival rates for juveniles (0.64) and full-grown (0.63) birds were similar, but the timing of mortality events differed between age-classes. We recommend that managers in Kansas, USA, focus on improving early survival of juveniles by providing additional food resources to chicks. This can be accomplished by manipulating vegetation to increase forb cover, which will result in increased invertebrate biomass.

Characteristics of nocturnal bird migration are poorly understood for many regions of the United States. This information will be critical in areas where wind power projects are proposed. We used portable marine radar to conduct a nocturnal bird migration study at multiple sites along the Allegheny Front, West Virginia, on 45 nights during autumn 2003, to document migration characteristics at a proposed wind power project. Nocturnal passage rates were highly variable among nights, ranging from 8 to 852 targets/km/hour, with a seasonal mean of 241 ± 33 targets/km/hour at the primary (central) study site and 199 targets/km/hour for the entire proposed development. Mean flight altitudes also were highly variable among nights, ranging from 214 to 769 m above ground level (agl), with a mean flight altitude of 410 ± 2 m agl. Flight directions indicated that most migrants crossed, rather than followed, the Allegheny Front ridgeline. We believe portable marine radars, when coupled with a rigorous study design, can collect important baseline information on avian migration and address site specific questions posed at proposed developments. Concurrent collection of low-altitude migration and avian fatality data could help elucidate which metrics are most useful for predicting avian fatalities at wind power developments.

In 1999 we surveyed 1,000 randomly selected South Dakota, USA, muzzleloader deer (Odocoileus spp.) hunters using a self-administered mail survey to gain better understanding of equipment used, skills, success, motivations, and attitudes about technology and restrictions. This sample represented 67% of the state's muzzleloader deer-hunter population in 1999. Nine hundred and four usable surveys were returned. We conducted a K-means cluster analysis to determine if muzzleloader hunters could be separated (based on equipment used) into modern and traditional hunters. Modern muzzleloader hunters (31%) used in-line muzzleloaders, bullet with sabot, Pyrodex pellets, or fiber-optic open sights, while traditional muzzleloader hunters (69%) used caplock muzzleloaders, black powder, or flintlock muzzleloaders. We compared hunter type, age, experience, skills, success, and equipment used by category to determine if differences existed. Most muzzleloader deer hunters (68%) were satisfied with current equipment regulations. Probability of hunter success increased when modern muzzleloader equipment was used and the distance hunters were willing to shoot at a standing deer increased. Equipment type only slightly impacted harvest success. Because more muzzleloader hunters were satisfied with equipment restrictions, we concluded that establishing additional limits was not necessary. Moreover, South Dakota wildlife managers already had a lottery quota system for permit allocation that could be used to adjust for increased muzzleloader harvest. Thus, we contend muzzleloader-equipment–regulation decisions for South Dakota hunters may be more a social than a biological issue.

Adaptive wildlife management seeks to improve the integration of science and management by focusing decision-making on hypothesis-testing and structuring management actions as field experiments. Since the early 1990s, adaptive resource management (ARM) has advocated enhancing scientific rigor in evaluating management actions chosen to achieve “enabling objectives” typically directed at wildlife habitat or population characteristics. More recently, the concept of adaptive impact management (AIM) has emphasized a need to articulate “fundamental objectives” in terms of wildlife-related impacts to be managed. Adaptive impact management seeks to clarify why management is undertaken in a particular situation. Understanding the “why” question is viewed in AIM as a prerequisite for establishing enabling objectives, whether related to changes in wildlife habitats and populations or to human beliefs and behaviors. This article describes practical aspects of AIM by exploring relationships between AIM and ARM within a comprehensive model of decision-making for wildlife management. Adaptive impact management clarifies and differentiates fundamental objectives (i.e., wildlife-related impacts to be modified) and enabling objectives (i.e., conditions that affect levels of impacts), whereas ARM reduces uncertainty about how to achieve enabling objectives and seeks an optimal management alternative through hypothesis-testing. The 2 concepts make different contributions to development of management hypotheses about alternative actions and policies and should be nested for optimal application to comprehensive wildlife management. Considered in the context of the entire management process, AIM and ARM are complementary ideas contributing to adaptive wildlife management.

One particularly complex issue confronting wildlife conservation is the role of regulated trapping as a management tool. Public opinion polls, recent ballot initiatives and referenda, and the continual introduction (and uneven success) of antitrapping legislation in state legislatures illustrate the intensity of public controversy surrounding trapping. Little is known, however, about the perspectives of wildlife and fisheries conservation professionals regarding traps and trapping. We conducted a survey to explore the attitudes and values of conservation professionals regarding a variety of conservation-related issues including whether to outlaw use of leghold traps. We sent a mailback questionnaire to a stratified random sample of 1,000 members each of The Wildlife Society, American Fisheries Society, North American Wildlife Enforcement Officers' Association, and Society for Conservation Biology. We achieved an 81% overall response rate. Respondents were divided on whether to outlaw leghold traps; 46% favored outlawing use of the leghold trap, 39% opposed outlawing its use, and 15% had no opinion. Those who favored outlawing leghold traps believed they cause unnecessary animal pain or stress, may harm nontargets, and are not a necessary management tool. The 3 most frequently mentioned reasons offered in support of not outlawing the leghold traps were efficiency of harvest, they are an important tool for managing furbearers, and that they did not adversely affect furbearer populations. Responses differed by organization membership, employer, gender, and whether or not respondents were a hunter and/or trapper. Our results suggest that conservation professionals may be as conflicted about use of the leghold trap as are public stakeholders. We believe our findings pose important questions that conservation professionals must consider if they are to provide the leadership to more effectively address wildlife management conflicts.

Although nutritional status in response to controlled feeding trials has been extensively studied in captive white-tailed deer (Odocoileus virginianus), there remains a considerable gap in understanding the influence of variable supplemental feeding protocols on free-ranging deer. Consequently, across the northern portion of the white-tailed deer range, numerous property managers are investing substantial resources into winter supplemental-feeding programs without adequate tools to assess the nutritional status of their populations. We studied the influence of a supplemental winter feeding gradient on the protein and energy status of free-ranging white-tailed deer in the Adirondack Mountains of New York. We collected blood and fecal samples from 31 captured fawns across 3 sites that varied considerably in the frequency, quantity, and method of supplemental feed distribution. To facilitate population-wide comparisons, we collected fresh fecal samples off the snow at each of the 3 sites with supplemental feeding and 1 reference site where no feeding occurred. Results indicated that the method of feed distribution, in addition to quantity and frequency, can affect the nutritional status of deer. The least intensively fed population showed considerable overlap in diet quality with the unfed population in a principal components ordination, despite the substantial time and financial resources invested in the feeding program. Data from fecal samples generally denoted a gradient in diet quality and digestibility that corresponded with the availability of supplements. Our results further demonstrated that fecal nitrogen and fecal fiber, indices of dietary protein and digestibility, can be estimated using regressions of fecal pellet mass, enabling a rapid qualitative assessment of diet quality.

Chronic wasting disease (CWD) was discovered in free-ranging white-tailed deer (Odocoileus virginianus) in south-central Wisconsin in 2002. The current control method for CWD in the state is the harvest of deer from affected areas to reduce population density and lower CWD transmission. We used spatial regression methods to identify factors associated with deer harvest across south-central Wisconsin. Harvest of deer by hunters was positively related to deer density (slope = 0.003, 95% CI = 0.0001–0.006), the number of landowners that requested harvest permits (slope = 0.071, 95% CI = 0.037–0.105), and proximity to the area of highest CWD infection (slope = −0.041, 95% CI = −0.056–−0.027). Concomitantly, harvest was not impacted in areas where landowners signed a petition protesting intensive deer reduction (slope = −0.00006, 95% CI = −0.0005–0.0003). Our results suggest that the success of programs designed to reduce deer populations for disease control or to reduce overabundance in Wisconsin are dependent on landowner and hunter participation. We recommend that programs or actions implemented to eradicate or mitigate the spread of CWD should monitor and assess deer population reduction and evaluate factors affecting program success to improve methods to meet management goals.

Most Dall's sheep (Ovis dalli dalli) population-monitoring efforts use intensive aerial surveys with no attempt to estimate variance or adjust for potential sightability bias. We used radiocollared sheep to assess factors that could affect sightability of Dall's sheep in standard fixed-wing and helicopter surveys and to evaluate feasibility of methods that might account for sightability bias. Work was conducted in conjunction with annual aerial surveys of Dall's sheep in the western Baird Mountains, Alaska, USA, in 2000–2003. Overall sightability was relatively high compared with other aerial wildlife surveys, with 88% of the available, marked sheep detected in our fixed-wing surveys. Total counts from helicopter surveys were not consistently larger than counts from fixed-wing surveys of the same units, and detection probabilities did not differ for the 2 aircraft types. Our results suggest that total counts from helicopter surveys cannot be used to obtain reliable estimates of detection probabilities for fixed-wing surveys. Groups containing radiocollared sheep often changed in size and composition before they could be observed by a second crew in units that were double-surveyed. Double-observer methods that require determination of which groups were detected by each observer will be infeasible unless survey procedures can be modified so that groups remain more stable between observations. Mean group sizes increased during our study period, and our logistic regression sightability model indicated that detection probabilities increased with group size. Mark–resight estimates of annual population sizes were similar to sightability-model estimates, and confidence intervals overlapped broadly. We recommend the sightability-model approach as the most effective and feasible of the alternatives we considered for monitoring Dall's sheep populations.

We evaluated the potential for different types of remote drug-delivery systems (RDDS) to injure target animals. We recorded dart velocity, time, and distance from projector muzzle at 8.5-millisecond intervals by Doppler radar chronograph for 4 types of RDDS. We used darts of different volume and unique combinations of charges, power settings, and distances in accordance to manufacturer's recommendations. Variation in the drop of repeated shots was >10 cm for 28 of 90 trials (5 replicates per trial) with heavy-mass darts having the lowest precision. Impact velocities were high (>50 m/sec) in many trials using heavy darts and some trials using light-mass, rapid-injection darts. We evaluated the permanent wound cavity (PWC) formed by firing dye-filled darts into ordnance gelatin covered tightly by a fresh elk hide and into the thighs of calf carcasses. Rapid-injection darts fitted with end-ported needles consistently 1) forced hair and skin beneath the hide; 2) formed a PWC that was 2–3× the needle length; and 3) pulled the hide away from the gelatin before the dye was completely ejected into the gelatin. We conclude injury to target animals is minimized in RDDS that use lightweight, slow-injection darts, fitted with side-ported needles and broad-diameter needle seals, and that impact target animals at moderate velocity (40–50 m/sec) with high precision. We recommend against using darts with rapid-injection mechanisms and end-ported needles because of their potential to cause deep, chronic wounds.

Aerial surveys are valuable tools for wildlife research and management. However, problems with safety, cost, statistical integrity, and logistics continue to impede aerial surveys from manned aircraft. The use of small, unmanned aerial vehicles (UAVs) may offer promise for addressing these problems and become a useful tool for many wildlife applications, such as for collecting low-altitude aerial imagery. During 2002 and 2003, we used a 1.5-m wingspan UAV equipped with autonomous control and sophisticated video equipment to test the potential usefulness of such an aircraft for wildlife research applications in Florida, USA. The UAV we used completed >30 missions (missions averaging 13 km linear distance covered) over 2 years before finally crashing due to engine failure. The UAV captured high-quality, progressive-scan video of a number of landscapes and wildlife species (white ibis [Eudocimus albus], other white wading birds, American alligator [Alligator mississippiensis], and Florida manatee [Trichechus manatus]). The UAV system was unable to collect georeferenced imagery and was difficult to deploy in unimproved areas. The performance of the autonomous control system and the quality of the progressive-scan imagery indicated strong promise for future UAVs as useful field tools. For small UAVs to be useful as management or research tools, they should be durable, modular, electric powered, launchable and recoverable in rugged terrain, autonomously controllable, operable with minimal training, and collect georeferenced imagery.

Methods that allow unbiased estimation of animal abundance are increasingly demanded in management and conservation. The use of these methods should respect their assumptions. The need for accurate distance measurements in distance-sampling surveys is stressed. Here we present 2 alternative methods for measuring distance from a line to an object during helicopter surveys: 1) using a Global Positioning System (GPS) unit, with distances measured using appropriate software; and 2) recording declination angles and altitudes, using basic trigonometry to obtain the appropriate distances. These are compared to distances measured by a laser rangefinder (assumed to be true distances). The effect of the different errors on estimated densities is assessed by simulation. The GPS method appeared to be very accurate, while a potential downward bias in estimated density could be present if the inclinometer method is used. We discuss the implication for wildlife studies of using different measurement methods leading to different errors.

We use survival analysis to compare failure of passive integrated transponder (PIT) tags and loss of metal ear tags in 2,277 southern flying squirrels (Glaucomys volans), 124 house mice (Mus musculus), 112 hispid cotton rats (Sigmodon hispidus), and 374 deer (Peromyscus maniculatus) and cotton mice (P. gossypinus). With the exception of cotton rats, failure rates between ear and PIT tags differed by species. Flying squirrels exhibited the highest proportional loss of both tag types and lost ear tags more readily than PIT tags failed. The opposite was true for cotton rats and deer and cotton mice. Most PIT tags appeared to fail shortly after implantation (≤3 days), except for flying squirrels and, to a lesser extent, cotton rats. Ear tags exhibited a consistent rate of loss in flying squirrels. Body mass did not influence failure of PIT tags; however, flying squirrel body mass was associated with increased loss of ear tags. For flying squirrels PIT tag failure increased with the number of times an individual had already received a PIT tag that failed. We provide recommendations for using PIT and ear tags in marking rodents based on species-specific patterns and suggest the combined use of external and internal markers to obtain the most reliable estimates of population parameters.

Conservation and management of snow leopards (Uncia uncia) has largely relied on anecdotal evidence and presence–absence data due to their cryptic nature and the difficult terrain they inhabit. These methods generally lack the scientific rigor necessary to accurately estimate population size and monitor trends. We evaluated the use of photography in capture–mark–recapture (CMR) techniques for estimating snow leopard population abundance and density within Hemis National Park, Ladakh, India. We placed infrared camera traps along actively used travel paths, scent-sprayed rocks, and scrape sites within 16- to 30-km² sampling grids in successive winters during January and March 2003–2004. We used head-on, oblique, and side-view camera configurations to obtain snow leopard photographs at varying body orientations. We calculated snow leopard abundance estimates using the program CAPTURE. We obtained a total of 66 and 49 snow leopard captures resulting in 8.91 and 5.63 individuals per 100 trap-nights during 2003 and 2004, respectively. We identified snow leopards based on the distinct pelage patterns located primarily on the forelimbs, flanks, and dorsal surface of the tail. Capture probabilities ranged from 0.33 to 0.67. Density estimates ranged from 8.49 (SE = 0.22) individuals per 100 km² in 2003 to 4.45 (SE = 0.16) in 2004. We believe the density disparity between years is attributable to different trap density and placement rather than to an actual decline in population size. Our results suggest that photographic capture–mark–recapture sampling may be a useful tool for monitoring demographic patterns. However, we believe a larger sample size would be necessary for generating a statistically robust estimate of population density and abundance based on CMR models.

Numerous techniques have been proposed to estimate or index cougar (Puma concolor) populations, but few have been applied simultaneously to populations with reliable estimates of population size. Between 1996 and 2003, we evaluated the relative efficacy and accuracy of multiple estimation and index techniques for populations at 2 locations in Utah, USA: Monroe Mountain and the Oquirrh Mountains. We used radiotagging followed by intensive monitoring and repeated capture efforts to approach a complete enumeration of the populations. We used these benchmarks to evaluate other population estimates (Lincoln–Petersen mark–recapture, helicopter-survey probability sampling, catch-per-unit-effort) and indices (scent-station visits, track counts, hunter harvest). Monitoring over 600 scent-station-nights using different attractants June–September in 1996 and 1997 yielded a single cougar visit. Summer track-based indices reflected a 54–69% reduction in population size on the Monroe site and a numerically stable population on the Oquirrhs, but relationships between indices and the benchmark population estimates varied among techniques. Aerial track surveys required sufficient fresh snowfall accumulations for adequate tracking coverage of a given unit, conditions that were met only once on one study site in each of 3 years. Population estimates derived from helicopter-survey probability sampling exceeded reference population estimates by 120–284%, and bootstrapped estimates of standard error encompassed 25–55% of the population estimates (e.g., 5.6 ± 1.4 cougars/100 km²). Despite poor performance in predicting cougar population sizes, track-based estimates may provide better indices for monitoring large changes in population trends (i.e., with low precision). However, we recommend using multiple indices after determination of a more rigorous initial population estimate for managing populations of conservation concern and when considering connectivity to determine potential refuge sites for regional management (e.g., management by zones).

Highway construction and expansion in bear habitat can negatively affect brown bear (Ursus arctos) populations. We analyzed radiotelemetry data from previous studies to determine the spatial and temporal distribution of brown bear crossings of the Sterling and Seward highways on the Kenai Peninsula, Alaska, USA. We compared highway crossings of actual bears to simulated bears to determine whether the highway acted as a barrier and whether crossing locations were spatially clustered. Four of 13 bears monitored crossed the highway less frequently than expected. While locations where bears crossed the highway were clustered, none of the spatial models we developed strongly explained the observed clustering. Bears were more likely to cross the highway during nighttime than daytime. When bears crossed the highway, they moved more rapidly and acutely than they did prior to or after the crossing. Further study is needed to determine the appropriate number and location for placement of highway-crossing structures in this region

The coyote lure operative device (CLOD) is a substance delivery system for coyotes (Canis latrans). Field testing has demonstrated that free-ranging coyotes will activate CLODs, but whether individual animals or mated pairs will do so repeatedly has not been examined. We conducted 2 experiments with captive coyotes to determine whether individual animals or mated pairs would approach and activate CLODs repeatedly when exposed to them in a familiar environment over 4 consecutive days. The second experiment allowed us to determine whether a bias existed toward either member of a pair when CLODs were activated. We concluded that individuals and mated pairs approach and activate CLODs with decreased latency over a 4-day testing period. Both sexes activated CLODs when encountered as individuals, but males activated more CLODs than females when mated pairs were exposed to the device. These results imply that an end user of the CLOD can wait until regular “take” occurs before introducing an active ingredient and, thus, have more control over delivery time.

The identification of carnivores responsible for preying on wild or domestic ungulates often is of interest to wildlife managers. Typically, field personnel collect a variety of data at mortality sites including scat or hair samples that may have been deposited by the predator. We compared mitochondrial DNA (mtDNA) analysis of hair and scat samples (n = 122) collected at elk (Cervus elaphus) mortality sites between 1997 and 2004 in north-central Idaho, USA, with field identification of carnivore presence. We amplified mtDNA from samples via a 2-step process involving an initial screening for American black bears (Ursus americanus), brown bears (Ursus arctos), and gray wolves (Canis lupus) using a length variation in the 5′ hypervariable section of the control region. Samples that failed the first screening subsequently were analyzed using conserved mtDNA primers that amplify a wide array of vertebrates. Species identification success rate was high (88.5%) and established the presence of 3 predators at elk mortality sites including black bears (55.7%), cougars (Puma concolor; 27.9%), and coyotes (Canis latrans; 6.6%). Attempts at hair and scat identification by field personnel were correct for 58% of hair samples and 79% of fecal samples. Results from these analyses demonstrate the merits of combining field mortality assessments with mtDNA species identification to aid wildlife managers in more accurately pinpointing predators involved in either predation or depredation events.

Throughout the range of swift fox (Vulpes velox), coyotes (Canis latrans) are the primary source of swift fox mortality. Coyotes may suppress swift fox populations where densities are high. Because coyote numbers have increased since wolves (Canis lupus) have been exterminated, we hypothesized that escape habitats may limit swift foxes. To test our hypothesis, we installed artificial escape dens in 3 spatially separated (treated) areas on the Rita Blanca National Grasslands in Dallam County, Texas, USA. From January 2002 to August 2004, we captured, radiocollared, and monitored 55 swift foxes. Annual swift fox survival in artificial escape-den–treated areas (Ŝ = 0.81) was higher than in untreated areas (Ŝ = 0.52, P = 0.07). Relative swift fox abundance was higher in treated than untreated areas in 2002 (Yates' χ² = 4.61, P = 0.03) and in 2003 (Yates' χ² = 4.70, P = 0.03) but not in 2004 (Yates' χ² = 2.67, P = 0.10). However, recruitment rates were no different between treated and untreated areas in 2002 (Yates' χ² = 0.21, P = 0.65) or 2003 (Yates' χ² = 0.41, P = 0.52). Ninety-five percent fixed-kernel estimates of home-range sizes revealed no difference (P = 0.91) between treated and untreated areas, but swift foxes increased their distribution by moving into an area that had been unoccupied for at least 3 years before this study. Our results suggest that artificial escape dens contributed to increasing swift fox distributions in our study area.

Researchers and managers have hypothesized that coyote (Canis latrans) incursions into deep snow areas, facilitated by packed trails created by snowmobiles, may negatively impact lynx (Lynx canadensis) populations through interference or exploitation competition. In response to this hypothesis, federal agencies have limited snowmobile use within potential lynx habitat. We used aerial track counts and ground tracking to compare coyote activity in deep snow areas with and without snowmobile trails on the Uinta Mountain Range of northeastern Utah, USA, and 3 comparable sites in the Intermountain West to test this hypothesis. Our analysis suggests that snowmobile trail presence is a good predictor of coyote activity in deep snow areas. Over 90% of coyote tracks observed in our study areas associated with a snowmobile trail were within 350 m of the trail. Snow depth and prey density estimates influenced whether a coyote returned to a snowmobile trail. Our results suggest that restrictions placed on snowmobiles in lynx conservation areas by land management agencies because of the potential impacts of coyotes may be appropriate.

Observing nocturnal, cryptic, highly mobile, or elusive wildlife in the field is difficult. Precise abundance estimates are necessary to make management decisions. Numerous methods have been examined to estimate wild turkey abundance with limited success. The use of forward-looking infrared (FLIR) technology has increased and may improve the detection of wildlife. We sought to estimate Rio Grande wild turkey (Meleagris gallopavo intermedia) abundance using FLIR surveys and to assess the accuracy of these estimates by comparing them with independent estimates from ground surveys. We conducted 8 ground and aerial FLIR surveys of roost sites in 3 distinct ecological regions of Texas, USA. We were unable to aerially detect roosting turkeys using the portable FLIR camera because of altitudinal restrictions required for safe helicopter flight and lack of thermal contrast. Flight altitude was a principal obstacle because topography and aerial obstructions (i.e., utility poles, towers, and wires) often required higher-altitude flights than ideal for turkey observation. From an aerial perspective, wild turkey thermal signatures were camouflaged by their surroundings. The external temperatures of turkeys, tree branches, and other background objects (e.g., rocks, bare ground) were within 1.5°C of each other despite ambient temperatures or other weather variables (i.e., wind speed, humidity, and cloud cover). Therefore, there was not sufficient difference in radiant temperature of a turkey and its background to permit adequate detection from an aerial perspective.

Resident Canada geese (Branta canadensis) nest or reside in the temperate latitudes of North America. In past years, translocation—the capture and subsequent release of geese at distant locations—has been used to establish resident goose populations and to reduce nuisance problems. However, with new special hunting seasons designed to target resident Canada geese, we can now evaluate translocation as a management tool when hunting is allowed at release sites. We selected 2 study sites, representative of urban and suburban locations with nuisance resident geese, in central and western New York, USA. In June 2003, we translocated 80 neck-banded adult geese, 14 radiomarked adult females, and 83 juveniles 150 km east and southwest from urban and suburban problem sites in western New York to state-owned Wildlife Management Areas. At these same capture sites, we used 151 neck-banded adult geese, 12 radiomarked females, and 100 juveniles as controls to compare dispersal movements and harvest vulnerability to translocated geese. All observations (n = 45) of translocated radiomarked geese were <20 km from release sites, in areas where hunting was permitted. Only 25 of 538 observations (4.6%) of radiomarked geese at control sites were in areas open to hunting. The remainder of observations occurred at nonhunting locations within 10 km of control sites. More translocated adult geese (23.8%) were harvested than control geese (6.6%; χ² = 12.98, P = 0.0009). More translocated juvenile geese were harvested (22.9%) than juvenile controls (5.0%; χ² = 12.30, P = 0.0005). Only 7 (8.8%) translocated adult geese returned to the original capture sites during Canada goose hunting seasons. Translocation of adult and juvenile geese in family groups may alleviate nuisance problems at conflict sites through increased harvest, reducing the number of birds returning in subsequent years.

Applying durable markings on semi-aquatic animals is a problem in field research. Methods used for live-trapping, handling, and marking of animals strongly depend on the species considered and the circumstances at particular study sites. I provide a short overview on methods used for capturing and marking nutrias (Myocastor coypus). This review is supplemented by field experiences gathered while studying an urban population in Germany. Using a dip net, I captured animals and handled them without immobilizing agents. I used ear tags, radiocollars, and passive integrative transponders (PITs) for individual marking. Based on my review and experiences, PITs are effective for long-term individual marking; however, an acceptable method for visual long-term identification of single nutrias is needed.

Although the importance of invertebrates to young galliforms has been demonstrated by numerous researchers, few comparisons of techniques designed to assess invertebrate availability for these species have been published. Our objective was to compare suction sampling and sweep-netting as methods for evaluating invertebrates available for Rio Grande wild turkey (Meleagris gallopavo intermedia) poults on the Edwards Plateau of Texas, USA. We collected invertebrates via sweep-netting (n = 102) and suction sampling (n = 100) during summers 2002 and 2003 at brood locations. Suction sampling collected the same orders of invertebrates as sweep-netting, but invertebrate dry mass and frequency of occurrence were lower for nearly every order compared to sweep-netting. Suction sampling provided no additional information to that obtained by sweep-netting in the broken grasslands where our study was conducted. For this reason, we believe the additional cost and time required to implement this technique was not warranted for our study areas.

Little information is known about the foraging habitat of Montezuma quail (Cyrtonyx montezumae) in Texas, USA. We compared habitat characteristics of foraging and nonforaging areas to identify trends in habitat attributes across sites with varying levels of quail use on Elephant Mountain Wildlife Management Area in Brewster County, Texas, USA, during May–August 2001. We delineated foraging and nonforaging areas using a system of parallel transects (100 m apart) that spanned the length of the grassland and covered the entire area. We walked transects every 3–5 days searching for signs of feeding (i.e., diggings). We documented a higher mean density of Allium spp. plants in foraging (95% CI: 12.1 ± 4.3 plants/m²) than nonforaging areas (95% CI: 0.8 ± 0.6 plants/m²). Foraging areas also exhibited a greater mean slope (95% CI: 22.6 ± 2.9% vs. 8.0 ± 2.1%). However, species richness, diversity, and equitability were similar between the foraging (23, 6.5, and 0.3, respectively) and nonforaging area (29, 7.6, 0.3). We observed a decreasing trend in density of Allium spp. plants, number of stones, and slope from high- to no-use sites. These 3 variables appear to be key habitat features associated with foraging areas of Montezuma quail in west Texas.

Increasing concerns about the exposure of mourning doves (Zenaida macroura) to spent lead shot may lead to a review of lead-shot restrictions. Policy reviews regarding current restrictions likely will involve debates about whether nontoxic-shot requirements will result in increased crippling loss of mourning doves. We evaluated waterfowl crippling rates in the United States prior to, during, and after implementation of nontoxic-shot regulations for waterfowl hunting. We use this information to make inferences about mourning dove crippling rates if nontoxic-shot regulations are enacted. We found differences in moving average crippling rates among the 3 treatment periods for ducks (F = 23.232, P < 0.001, n = 49). Prenontoxic-shot-period crippling rates were lower than 5-year phase-in period crippling rates (P = 0.043) but higher (P < 0.001) than nontoxic-shot-period crippling rates. Similarly, we observed differences in moving average crippling rates among the 3 treatment periods for geese (F = 9.385, P < 0.001, n = 49). Prenontoxic-shot- and 5-year-phase-in-period crippling rates were both greater than (P < 0.001) nontoxic-shot-period crippling rates but did not differ from one another (P = 0.299). Regardless of why the observed increases occurred in reported waterfowl crippling rates during the phase-in period, we believe the decline that followed full implementation of the nontoxic-shot regulation is of ultimate importance when considering the impacts of lead shot restrictions for mourning doves. We argue that long-term mourning dove crippling rates might not increase as evidenced from historical waterfowl data.

Noel et al. (2004) claimed that oil development on Alaska's North Slope has not adversely affected caribou (Rangifer tarandus) distribution. Their argument was based on the lack of statistical difference between caribou densities at different distances from the Milne Point road, Prudhoe Bay, Alaska, USA,10–20 years after its construction. Our primary criticisms of that article are that the authors failed to include the effects of expanding oilfield infrastructure in their analysis, to incorporate 6 of 13 surveys, and to discuss data that revealed caribou largely abandoned their study area following this development. After the construction of the road, calving caribou were displaced from a previously used zone 0–4 km from the road, which subsequently increased use 4–6 km away from the road in the years spanning 1982–1987. With additional development of roads and pads in the calving grounds after 1987, affecting 92% of the study area, the remaining undisturbed fragments were too small for continued use of the area for concentrated calving. Our analysis of the Noel et al. data shows an overall gradual abandonment of the oilfield during calving and a drop in abundance of calving caribou by at least 72% within the oilfield, in spite of the fact that the total herd size had increased 4- to 5-fold during that time period. The major concentration of calving shifted to south of the oilfield, whereas such shifts in calving did not occur in the eastern portion of the Central Arctic Herd that was less affected by development.

Joly et al. (2006) critically reviewed our paper (Noel et al. 2004) describing caribou (Rangifer tarandus) distribution data in relation to an oilfield road in Alaska, USA. Their review focused on 4 primary points: 1) we concluded there were no adverse impacts to caribou distribution, 2) we failed to discuss data that revealed caribou abandoned the study area following additional development of gravel roads and pads, 3) we failed to consider expanding infrastructure and some surveys, and 4) our conclusions contradict others' findings. We did not draw conclusions, but rather presented our data and analyses and discussed possible explanations for our observations. We presented all of the original data showing a decline in caribou use of the area during calving and discussed potential influential factors. We discussed our method and rationale for the focus of our analysis on displacement from the Milne Point Road in order to replicate methods used in an earlier study. The fourth point reflects that we simply had different results from those of other studies.

I compared 101 wolf (Canis lupus) pack territories formed in Wisconsin during 1993–2004 to the logistic regression predictive model of Mladenoff et al. (1995, 1997, 1999). Of these, 60% were located in putative habitat suitabilities <50%, including 22% in suitabilities of 0–9%. About a third of the area with putative suitabilities >50% remained unoccupied by known packs after 24 years of recolonization. This model was a poor predictor of wolf re-colonizing locations in Wisconsin, apparently because it failed to consider the adaptability of wolves. Such models should be used cautiously in wolf-management or restoration plans.

An accompanying article in this issue of the Bulletin (Mech 2006) purports to critique our past research. L. D. Mech attempts to show that our model of prospective, preferred gray wolf (Canis lupus) habitat (Mladenoff et al. 1995, 1997, 1999, Mladenoff and Sickley 1998) has been incorrect. We first state clearly that we are not opposed to the re-assessment of our work based on new data. However we believe the Mech paper contains both serious conceptual and methodological flaws that render its conclusions invalid. Our own analysis, based on logic and current techniques (Mladenoff et al. 2005), shows that the model has behaved according to our predictions and continues to successfully predict wolf recolonization in Wisconsin, USA, over more than 25 years. However, the serious flaws of Mech (2006) alone show that he is incorrect in his putative critique of our work.

I contend the Mladenoff et al. (2006) rebuttal to my article (Mech 2006), “Prediction failure of a wolf landscape model,” itself fails. Mladenoff et al. (2006:878) provide no data to support their claim that the model “...continues to successfully predict wolf recolonization in Wisconsin, USA, over more than 25 years.” I find this critical lack of supporting data puzzling, and it substantiates why I felt obligated to publish my original cursory analysis (Mech 2006). Prior to preparing my manuscript, I tried for several years to persuade Mladenoff et al. to conduct a Geographic Information Systems test of their model using the data available from 101 new wolf-pack territories. I believe in the absence of these data, my analysis is appropriate.

Biologists rely on published scientific papers to increase their knowledge and to guide their future work. Papers comparing techniques can be especially influential when several options exist for accomplishing a task. In this paper, I use a recent publication comparing the effects on birds of several methods for attaching or implanting radio transmitters to illustrate the need for clear and accurate reporting of the techniques used. Because of deficiencies in methodology, in stating methodology, and in following cited methodology I argue that the conclusions drawn by the authors are not supportable.

We respond here to a critique of our paper (Small et al. 2004b) regarding the methodology used to implant subcutaneous transmitters in white-winged doves (Zenaida asiatica). We agree with Mulcahy (2006) that more information regarding the methodology we used would have been appropriate. However, we refute the contention that we could not have followed the surgical protocol we cited and that protocols were not sterile. We believe this misinterpretation of our methods comes from a failure to note some of the finer points reported in our methodology. We address each issue made by Mulcahy (2006) in this response.