Understanding predator–prey relations is critical for management and conservation of species. Common descriptions of predator–prey dynamics often imply that low population density of prey, prey switching by predators, and high fecundity or productivity of prey are important in allowing prey species to coexist with predators. Studies of the effects of introduced predators on prey species do not support the idea that low prey density, switching by predators, and fecundity of prey are vital to coexistence of predator and prey. More likely, prey have a suite of morphological and behavior adaptations, including uses of specific habitat features, that render some individuals far less vulnerable to predation and allow predators and prey to coexist. Management activities designed to maintain desired prey species should include maintaining or enhancing features of habitat that reduce prey vulnerability.

Bart et al. (2004) develop methods for predicting needed samples for estimation of long-term trends from count survey data, and they apply these methods to the North American Breeding Bird Survey (BBS). They recommend adding approximately 40% more survey routes in the BBS to allow for estimation of long-term (i.e., 20 year) trends for a collection of species. We critique several aspects of their analysis and suggest that their focus on long-term trends and expansion of the present survey design will provide limited benefits for conservation because it fails to either enhance the credibility of the survey or better tie the survey to regional management activities. A primary innovation claimed by Bart et al. (2004) is the incorporation of bias in estimation in study planning. We question the value of this approach, as it requires reliable estimates of range of future bias. We show that estimates of bias used by Bart et al. (2004) are speculative. Failure to obtain better estimates of this bias is likely to compromise the credibility of future analyses of the survey. We also note that the generic analysis of population trends that they provide is of questionable validity and is unlikely to be relevant for regions and species of management concern.

Bart et al (2004a) proposed several approaches for enhancing the considerable value of the Breeding Bird Survey (BBS). Sauer et al. (2005) critiqued some of these approaches, and emphasized alternative goals for the survey. We agree with many of the suggestions of Sauer et al. (2005); notably that multispecies, large-scale surveys such as the BBS are most valuable for bird conservation if they achieve multiple objectives. Nevertheless, we strongly assert that estimation of long-term trends is of fundamental importance for identifying important conservation issues and determining which species represent priorities for conservation efforts, as has been repeatedly demonstrated in the past. We are confident that our recommendations for enhancing the ability of the BBS to detect trends—reducing bias, explicitly recognizing that all bias cannot be eliminated, and increasing sample size in poorly covered areas—can only enhance, and not detract from, the value of the BBS for other purposes.

The shift from single species conservation initiatives to multiple-species conservation plans has not been accompanied by parallel changes in methods to evaluate the success of these efforts, nor to provide managers critical information to employ adaptive management strategies. Layering single species approaches for monitoring multiple-species conservation plans is inefficient and may lead to management strategies that have unintended detrimental impacts on target and nontarget organisms. Alternative approaches, such as ecosystem monitoring, can also fail to provide adequate protection for listed species and so may not fulfill regulatory requirements. We propose a hybrid approach that employs conceptual and spatial data in an iterative process to create niche models for species and species associations within natural communities. Niche models are composed of testable hypotheses linking species occurrences to environmental parameters over multiple scales. During an initial data gathering period these hypotheses are evaluated, accepted or rejected, and modified as indicated by new data. Once niche models are corroborated, the focus of monitoring shifts to a greater emphasis on identified anthropogenic and natural environmental drivers of species occurrence and abundance. The focus on environmental drivers supplies managers with direct information as to how, when, and where to employ adaptive management strategies when natural variance in those drivers is compromised by anthropogenic stressors. We provide a specific example on the conceptualization, development, and implementation of our hybrid approach from a new Multiple-species Habitat Conservation Plan for the Coachella Valley, in the Colorado desert of southern California.

The concept of an animal's home range has evolved over time, as have methods for estimating home-range size and shape. Recently, home-range estimation methods have focused on estimating an animal's utilization distribution (UD; i.e., the probability distribution defining the animal's use of space). We illustrate the importance of the utilization distribution in characterizing the degree of overlap between home ranges (e.g., when assessing site fidelity or space-use sharing among individuals). We compare several different statistics for their ability to accurately rank paired examples in terms of their degree of overlap. These examples illustrate limitations of indices commonly used to quantify home-range overlap and suggest that new overlap indices that are a function of the UD are likely to be more informative. We suggest 2 new statistics for measuring home-range overlap: (1) for a measure of space-use sharing, we suggest a generalization of Hurlbert's (1978) E/E_uniform statistic, which we term the utilization distribution overlap index (UDOI), and (2) for a general measure of similarity between UD estimates, we suggest Bhattacharyya's affinity (BA; Bhattacharyya 1943). Using a short simulation study, we found that overlap indices can accurately rank pairs of UDs in terms of the extent of overlap, but estimates of overlap indices are likely to be biased. The extent of the bias depended on sample size and the degree of overlap (UDs with a high degree of overlap resulted in statistics that were more biased [low]), suggesting that comparisons across studies may be problematic. We illustrate the use of overlap indices to quantify the degree of similarity among UD estimates obtained using 2 different data collection methods (Global Positioning Systems [GPS] and very high frequency [VHF] radiotelemetry) for an adult female northern white-tailed deer (Odocoileus virginianus) in north-central Minnesota.

Genetic data can provide a powerful tool for those interested in the ecology and management of wildlife, especially when it is combined with behavioral, demographic, or spatial information. Although the full potential of genetic approaches to the study of wildlife populations has yet to be realized, the application of genetic analyses is becoming increasingly feasible and cost-effective. This is due primarily to recent advances in the number and types of genetic markers available, the development of sophisticated data analysis methods, and increased automation of laboratory instrumentation. These technological advances have broadened the list of questions that can be answered with genetic data, allowing inference at multiple levels of resolution (inter-individual to inter-specific) and temporal and spatial scales. Genetic data can be used to assess mating systems, hybridization, gene flow, effective population size, and population viability. Genetic data can also be used to define management units; identify individuals, sex, and species; and to provide insights into demographic patterns associated with the reduction and expansion of populations. All of these factors are either related to a species' ecology or provide important information for management and conservation. We describe some applications of genetic data, discuss processes affecting genetic variation within and among populations, and provide an overview of genetic terminology and how genetic variation is measured. As genetic methods become progressively more accessible and adaptable to an ever-widening array of questions, it is expected that they will play an increasingly important role in the ecology and management of wildlife.

The effective population size (N_e) provides information on how fast genetic variation is being lost, or relatedness is increasing, in a population of interest. This parameter is often considered to be related to population viability. Genetic approaches offer several avenues for estimating N_e; recent developments have helped relax assumptions of closed populations and stable population sizes that have hindered the estimation of N_e in many wildlife populations. The most promising areas of development are in the assessment of temporal changes in genetic composition for the estimation of contemporary N_e and the application of coalescent theory for estimation of historical N_e. Application of most estimators still requires making some questionable assumptions about wildlife populations. In general, these methods will be most beneficial when used in conjunction with current and historical demographic information.

Historically, novel molecular techniques have been developed by the human genetics community, adapted for nonhuman organisms by evolutionary biologists, and gradually adopted by the wildlife and fisheries communities. Today, evolutionary biologists routinely rely on molecules to assess mate choice, dispersal, parentage, sex ratios, and other population parameters. All in all, the use of molecular genetic markers has revolutionized population biology—human and otherwise. Prescient wildlife and fisheries biologists have recognized the importance of this revolution and are now using molecular genetic tools to evaluate captive or supplemental breeding programs, population dynamics, stocking strategies, and taxonomic issues. Herein, I explore the use of molecular genetic markers to address questions in wildlife biology and management. Specifically, I review how—among other topics—cannibalism, sex-ratios, dispersal, enumeration, genotoxicology, hybridization, and genetically modified organisms can be evaluated in the context of parentage, relatedness, and fitness. As science becomes more integrative and complex, it is easy to envision a future where collaborations between geneticists (who may not have the expertise to obtain the field samples) and wildlife biologists (who may not have the expertise and/or facilities to obtain the genotypes) are common and serve to answer both fundamental and applied questions.

Noninvasive genetic sampling provides great potential for research and management applications in wildlife biology. Researchers can obtain DNA from a variety of sources including hair, feces, urine, feathers, shed skin, saliva, and egg shells without handling or observing animals. These samples can then be used to identify the presence of rare or elusive species, count and identify individuals, determine gender, and identify diet items, or samples can be used to evaluate genetic diversity, population structure, and mating system. We review the recent advancements and techniques used for identifying species, individuals, and gender. We also address the potential pitfalls of noninvasive genetic sampling and provide recommendations for laboratory- and field-based methods to improve the reliability and accuracy of data collected from noninvasive genetic samples.

Molecular-genetic technology and statistical methods based on principles of population genetics provide valuable information to wildlife managers. Genetic data analyzed in a hierarchical, spatial context among individuals and among populations at micro- and macro-geographic scales has been widely used to provide information on the degree of population structure and to estimate rates of dispersal. Our goals were to (1) provide an overview of spatial statistics commonly used in empirical population genetics, and (2) introduce analytical designs that can be employed to extend hypothesis-testing capabilities by incorporating space-time interactions and by using information on habitat quality, distribution, and degree of connectivity. We show that genetics data can be used to quantify the degree of habitat permeability to dispersal and to qualify the negative consequences of habitat loss. We highlight empirical examples that use information on spatial genetic structure in areas of harvest derivation for admixed migratory species, wildlife disease, and habitat equivalency analysis.

The use of short tandem repeats (STRs) for the identification of animals has developed alongside similar STR applications for humans. Population studies, kinship analysis, paternity testing, and unique identification have been applied to humans and many other animals. The field of forensic science has adapted this information extensively in the prosecution of suspected criminals with great success. The power of human DNA testing is demonstrated routinely by the convictions and exonerations of individuals. We discuss how the use of nonhuman DNA testing is beginning to find a place in the prosecution of individuals. Animal evidence can be an important element in a case when used to establish an association between a crime scene and a suspect or in crimes involving a specific animal. Although the testing of animal evidence may be routine, its use in court is far less common. As the presentation of animal evidence in court increases, appropriate standards and guidelines must be applied to assure the admissibility of the DNA testing results in court. This requires rigorous validation of precision and accuracy, allele heritability and independence, accurate sampling, evidence handling, and appropriate statistical evaluation of the results before the criminal courts will accept and apply the power of DNA testing in cases involving animals.

In 1969, 17 pronghorn were reintroduced onto Umatilla Army Base in Oregon with no subsequent translocations or immigration into this fully enclosed area. We explored the genetic signature this event left on the population using a combination of microsatellite genotypes and mitochondrial DNA (mtDNA) sequencing data of this population. We compared the present day Umatilla herd to its source population and to a southeastern Oregon population. We found the reintroduced population had sharply lower genetic diversity compared to its source despite its rapid increase in population size following the initial founding event. It is likely the observed loss of diversity and the significant differentiation observed between the Umatilla herd and its source was a function of the low number of founders and stochastic losses of diversity in subsequent generations. We observed significant haplotypic and genotypic differentiation between the reintroduced population and its source (G_ST = 0.063, F_ST = 0.078, p < 0.001) that was approximately 3.5 times that found between the source and the southeastern population (G_ST = 0.018, F_ST = 0.021, p < 0.001). Moreover, 2 rare alleles in the source population were found in high frequency in the translocated population. The founding effect, stochastic shifts in allele frequencies each generation, restricted gene flow, and variance in the segregation of alleles related to a polygamous mating system have contributed to the significant differentiation observed between the Umatilla herd and its source. The results of this study can be applied directly to the management of ongoing translocation activities within Oregon.

Chemicals that reduce food intake by stimulation of satiation receptors could offer a novel, nonlethal method of reducing feeding damage to crops or stored products by vertebrate pests. Such chemicals result in a deep-seated, physiological response whose effects on feeding are unlikely to wane through habituation. We describe a preliminary evaluation of the potential for the use of satiety stimulants (i.e., feeding inhibitors) in wildlife management. Using rats (Rattus norvegicus) as the model system, we carried out trials to determine the effects of oral administration of 5 putative feeding inhibitors on food intake. We found that the most promising compounds 2-buten-4-olide (2-B40) and 5-hydroxy-L-tryptophan (5-HTP) reduced the food intake of all rats, irrespective of gender or prior feeding status. We observed the maximum reduction in food intake (53%) in hungry rats during the first hour following gavage with 5-HTP (100 mg/kg). In 2-choice feeding tests, we found 2-B40 and to a lesser extent 5-HTP, to be unpalatable to rats, hence these putative wildlife management agents may also act as feeding deterrents (repellents). We successfully identified compounds that were effective at reducing feeding in rats. Further research is required to define the range of applications for these materials in wildlife management.

We conducted a 2-year study of terrestrial habitat use by spotted salamanders (Ambystoma maculatum), blue-spotted salamanders (A. laterale), wood frogs (Rana sylvatica), and eastern newts (Notophthalmus viridescens) within blocks of forest enclosed by drift fencing and pitfall traps in the vicinity of a single breeding pond. Adult winter densities within forest habitat <100 m from the breeding pond were low for all species (range 0.1–1.9 individuals / 100 m², n = 6 enclosures). During our 2-year study, at least 40% of wood frogs, 52% of blue-spotted salamanders, and 60% of spotted salamanders wintered >100 m from the breeding pond. Males tended to winter closer to the breeding pond than did females. Adult wood frogs and eastern newts were largely absent from upland forest adjacent to the breeding pond during spring and summer, but they entered these areas in significant numbers to winter. Analyses of net flow of amphibians resulting from fall movement suggest that summer and winter densities of Ambystoma salamanders remained similar, while there were large increases in wood frog and eastern newt densities within terrestrial habitats near the breeding pond during fall. These results support a growing body of evidence that maintenance of suitable terrestrial habitat beyond 100 m from breeding pools is important for maintaining pool-breeding amphibian populations. Narrow protected buffer strips around breeding ponds might be even less effective than previously thought due to the disproportionate representation of males within these areas.

Dramatic changes in wintering distributions of Canada geese (Branta canadensis) have occurred over the past 50 years in eastern North America. Declines in numbers of subarctic-nesting geese wintering in southern states, and increases in numbers wintering in northern regions, have resulted in a northern shift in winter distributions. In contrast, numbers of temperate-nesting geese have increased throughout eastern North America. Management efforts to control overabundant temperate-nesting flocks have included the establishment of special early harvest seasons in September. However, the effect of early seasons on survival and harvest of subarctic-nesting populations has not been documented. Understanding the timing of migration movements and the fidelity of subarctic-nesting flocks to terminal winter refuges in the Southeast also is necessary to design early harvest seasons that target temperate-nesting flocks and protect subarctic-nesting populations. We used recoveries of marked geese to estimate survival and harvest rates before and after implementation of early harvest seasons within the Mississippi Flyway during 1976–1999. In addition, we used observations of neck-banded geese from the Southern James Bay Population (SJBP) to evaluate the hypothesis that subarctic-nesting geese arriving prior to mid-December on several key terminal winter refuges in the Southeast (early arriving migrants) were more likely to return to those refuges in subsequent years than were migrants arriving after mid-December (late arriving migrants). September seasons during 1987–1994 were a minor source of mortality for subarctic-nesting populations and accounted for <10% of their annual harvest mortality. The effectiveness of early seasons for increasing mortality of temperate-nesting flocks varied among the states we examined and was tempered by concurrent changes in state-specific harvest regulations during the regular harvest season. For SJBP Canada geese, annual fidelity to southeastern refuges was 10% higher for early arrivers than for late arriving geese. However, in any given year only 47–57% of the surviving geese were expected to return to the refuges the following year. Although early arriving migrants had higher survival and higher return probabilities than did late arriving migrants or geese that failed to return, numbers of geese wintering on southeastern refuges likely declined because <60% of the surviving geese affiliated with the refuges would return in a given year and because of lower survival for geese that did not return to the refuges.

We studied survival and movement of Australasian shoveler (Anas rhynchotis) using 883 band recoveries reported by hunters from 4,080 adult and 881 pre-fledged juveniles banded in 2 regions of New Zealand between 1972 and 1985. We fitted several band-recovery models including ones in which the logit of the survival probability was modelled as a linear function of age, sex, banding location, and time. We also fitted models in which the time-effect was expressed as a function of the El Nino-Southern Oscillation index (SOI). In a year in which the SOI was zero (neither El Niño nor La Niña conditions) the survival probability for adult males banded in Otago was an estimated 0.610 (SE = 0.058). The odds of survival for male and female juvenile shoveler were an estimated 0.605 (SE = 0.125) times that for adults; the odds of survival for juvenile and adult females were an estimated 0.631 (SE = 0.129) times the odds of survival for males; and the odds of survival for all birds banded in Southland were an estimated 1.550 (SE = 0.305) times the odds of survival for birds banded in Otago. For birds banded in Southland and Otago, large negative values of the SOI were associated with higher survival and decreased movement of birds away from the banding site. For birds banded in Waikato, the estimated survival probability for males in a year with SOI = zero was 0.724 (SD = 0.045). Across all years, the odds of survival for females were an estimated 0.720 (SD = 0.11) times that of males. In Waikato, El Niño conditions were associated with lower survival and increased movement of birds away from the banding site. We recommend that northern and southern populations of shoveler be managed as separate populations.

We used radiotelemetry to examine foraging habitat preferences of 17 breeding, male northern goshawks (Accipiter gentilis) in Minnesota from 1998–2000. We assessed habitat preference using radio relocation points and 50-m radius buffers of radio relocation points. Our data suggested that foraging male goshawks used early-successional upland conifer stands (≥25 yrs old), early-successional upland deciduous stands (≥50 yrs old), late-successional upland conifer stands (≥50 yrs old), and late-successional upland deciduous stands (≥50 yrs old) more frequently than expected based on the abundance of these vegetation types in the landscape. The 2 most available stand types, early-successional upland deciduous (<25 yrs old) and all ages of late-successional lowland conifer stands, were used less than expected by foraging goshawks. Late-successional lowland deciduous stands (≥50 yrs old) were used in proportion to availability. Although analysis of relocation points suggested early-successional upland deciduous stands (25–49 yrs old) and late-successional upland conifer stands (≥50 yrs old) were used in proportion to availability, analysis of buffers around relocation points indicated that these stand types were also used more than expected by foraging goshawks. Regardless of vegetation community type, stands used by goshawks were structurally similar with high canopy and understory stem densities, high canopy closure, substantial shrub cover, and large amounts of woody debris. Nest stands consisted of taller and larger diameter canopy trees and fewer understory trees than foraging stands, but stands were otherwise similar in structural features, suggesting goshawks used similar stands for nesting and foraging but that they tended to select the most mature stands for nesting. A commonality among nesting and foraging stands was the presence of open spaces between the canopy and understory foliage, and between understory and shrub layer foliage. In our study area, these spaces may have served as relatively unobstructed flight paths where foraging and nesting stands possessed stem densities at the upper end of that reported for goshawk habitat.

Implementation of the Conservation Reserve Program (CRP) altered the interspersion and abundance of patches of different land-cover types in landscapes of the southeastern United States. Because northern bobwhites (Colinus virginianus) are experiencing significant population declines throughout most of their range, including the Southeast, it is critical to understand the impacts of landscape-scale changes in habitat on their reproductive rates. Our objective was to identify components of landscape structure important in predicting nest site selection by bobwhites at different spatial scales in the Upper Coastal Plain of Georgia. We used a Geographic Information System (GIS) and spatial analysis software to calculate metrics of landscape structure near bobwhite nest sites. Logistic regression was used to model the relationship of nest sites to structure within the surrounding landscape at 4 spatial scales. We found that patch density and open-canopy planted pine were consistently important predictor variables at multiple scales, and other variables were important at various scales. The density of different patch types could be increased by thinning rows of pines in large monotypic stands of closed-canopy planted pine stands. Thinning and creating openings in CRP pine plantations should provide increased nesting opportunities for bobwhites. We interpret the support for other variables in our analysis as an indication that various patch configuration lead to different combinations of landscape structure that provide an acceptable range of habitat conditions for bobwhites.

Conservation of the eastern subspecies of the American oystercatcher (Haematopus palliatus palliatus) is a high priority in the U.S. Shorebird Conservation Plan, but previous population estimates were unreliable, information on distribution and habitat associations during winter was incomplete, and methods for long-term monitoring had not been developed prior to this survey. We completed the aerial survey proposed in the U.S. Shorebird Conservation Plan to determine population size, winter distribution, and habitat associations. We conducted coastal aerial surveys from New Jersey to Texas during November 2002 to February 2003. This area comprised the entire wintering range of the eastern American oystercatcher within the United States. Surveys covered all suitable habitat in the United States for the subspecies, partitioned into 3 survey strata: known roost sites, high-use habitat, and inter-coastal tidal habitat. We determined known roost sites from extensive consultation with biologists and local experts in each state. High-use habitat included sand islands, sand spits at inlets, shell rakes, and oyster reefs. Partner organizations conducted ground counts in most states. We used high resolution still photography to determine detection rates for estimates of the number of birds in particular flocks, and we used ground counts to determine detection rates of flocks. Using a combination of ground and aerial counts, we estimated the population of eastern American oystercatchers to be 10,971 /− 298. Aerial surveys can serve an important management function for shorebirds and possibly other coastal waterbirds by providing population status and trend information across a wide geographic scale.

We studied a local population of mountain plovers (Charadrius montanus) in southern Phillips County, Montana, USA, from 1995 to 2000 to estimate annual rates of recruitment rate (f) and population change (λ). We used Pradel models, and we modeled λ as a constant across years, as a linear time trend, as year-specific, and with an additive effect of area occupied by prairie dogs (Cynomys ludovicianus). We modeled recruitment rate (f) as a function of area occupied by prairie dogs with the remaining model structure identical to the best model used to estimate λ. Our results indicated a strong negative effect of area occupied by prairie dogs on both λ (slope coefficient on a log scale was −0.11; 95% CI was −0.17, −0.05) and f (slope coefficient on a logit scale was −0.23; 95% CI was −0.36, −0.10). We also found good evidence for a negative time trend on λ; this model had substantial weight (w_i = 0.31), and the slope coefficient on the linear trend on a log scale was −0.10 (95% CI was −0.15, −0.05). Yearly estimates of λ were >1 in all years except 1999, indicating that the population initially increased and then stabilized in the last year of the study. We found weak evidence for year-specific estimates of λ; the best model with year-specific estimates had a low weight (w_i = 0.02), although the pattern of yearly estimates of λ closely matched those estimated with a linear time trend. Insouthern Phillips County, the population trend of mountain plovers closely matched the trend in the area occupied by black-tailed prairie dogs. Black-tailed prairie dogs declined sharply in the mid-1990s in response to an outbreak of sylvatic plague, but their numbers have steadily increased since 1996 in concert with increases in plovers. The results of this study (1) increase our understanding of the dynamics of this population and how they relate to the area occupied by prairie dogs, and (2) will be useful for planning plover conservation in a prairie dog ecosystem.

The California spotted owl (Strix occidentalis occidentalis) has been at the center of political and administrative debate due to its association with commercially valuable forest. Several studies have compared the forest cover types used by California spotted owls with the cover types that are generally available, establishing the association between spotted owls and old/large tree components of forests at the landscape scale. We sought a deeper understanding of spotted owl habitat associations in areas in which owls had already selected territories. We mapped and classified vegetation within circular plots (radius 2.4 km) around 67 spotted owl sites in northeastern California, USA. We evaluated the relationships between habitat composition within the different owl sites and variation in (1) nest success (1990–2000) and (2) site occupancy, apparent survival probability, and reproductive output (1993–1998). All analyses included data representing 2 spatial scales: core area (814 ha) and nest area (203 ha). Site occupancy was positively associated with the amount of the nest area dominated by large trees with high canopy cover within the nest area. It was negatively associated with the amount of nonhabitat (nonforested areas and forest cover types not used for nesting or foraging) and with medium-sized trees with high canopy cover. Site occupancy also decreased with time and elevation. Apparent survival probability varied annually and was positively related to the area of each habitat class multiplied by the quotient proportion used/proportion available for each type, at both the nest and core scales. Reproductive output was negatively related to elevation and nonhabitat within the nest area. Nest success was positively associated with the presence of large remnant trees within the nest stand.

Numbers of American woodcock (Scolopax minor) males counted on the annual singing ground survey (SGS) have declined over the last 35 years at an average rate of 2.3% per year in the Eastern Region and 1.8% per year in the Central Region. Although hunting was not thought to be a cause of these declines, mortality caused by hunters can be controlled. Furthermore, there has been no research on effects of hunting mortality on woodcock populations at local and regional levels on the breeding grounds. We used radiotelemetry to determine survival rates and causes of mortality for 913 woodcock captured during fall 1997–2000 on 7 areas in Maine, New Hampshire, Pennsylvania, and Vermont, USA. Three of 7 sites were closed to hunting. For all sites and all years combined, 176 woodcock died, and 130 were censored, of which 39 were censored mortalities. Predation was the major (n = 134, 76%) cause of mortality. Mammals accounted for 56% of the predation, raptors accounted for 25%, and 19% was attributed to unknown predators. On hunted sites, 36% of the total mortality (n = 102) was caused by hunting, 63% by predation, and 1 bird starved. Kaplan-Meier survival curves did not differ between hunted and non-hunted sites among years (P = 0.46). Overall, point estimates of survival did not differ (P = 0.217) between hunted (SR = 0.636, SE = 0.04) and nonhunted sites (SR = 0.661, SE = 0.08). We modeled hazard rates from hunting and natural mortality events using program MARK. Akaike's Information Criterion supported using a model with common constant hazards from both hunting and natural causes for groups of sites. Groupings of sites for hazard rates from natural causes were not influenced by whether a site was hunted or not. Models detected no effects of woodcock age and sex (P = 0.52) on survival. Proportional hazards models comparing hunted and nonhunted sites found no effects of age and sex (P = 0.45), interactions of age, sex, capture weight, and bill length (P ≥ 0.269). Our data suggest that current hunting regulations are not causing lower survival of woodcock.

We examined cavity-nesting bird use of natural snags (n = 221) and 10- to 12-year-old snags (n = 836) created by topping mature conifers in 3 silvicultural treatments (group-selection cuts, 2-story regeneration harvests, clearcuts with retained trees) and 2 snag arrangements (clustered, scattered) in 30 Douglas-fir (Pseudotsuga menziesii) stands in the Oregon Coast Range. Eight bird species nested in created snags. Open-canopy stands (2-story and clearcut treatments) had higher levels of avian nesting, species richness, and species diversity compared to closed-canopy, group-selection stands. We did not find a difference in nesting levels between clustered and scattered snags. In created snags, most active nests were in the top 25% of the bole, cavity entrances typically faced northeast, and the presence of dead branches did not alter use of snags for nesting. Topped conifers that remained alive (n = 102) were rarely used for nesting or foraging. Since the last survey 6 years prior to our survey, the number of cavities per created snag per silvicultural treatment increased 3.3- to 6-fold, and we observed 4 additional avian species nesting; 3 were secondary cavity nesters. Total cavities per snag averaged 5.1, 4.3, and 2.5 for created snags, natural snags >12 years old, and natural snags <12 years old, respectively. Only 1 created snag fell in the decade since topping. Natural new snag recruitment resulting from residual green tree mortality was highest in 2-story stands (0.76 snag/ha) and lowest in clearcuts (0.20 snag/ha). Snags created by topping large conifers provided nesting and foraging structures for cavity-nesting birds under a range of silvicultural conditions, and use was influenced more by residual green tree density than snag arrangement. In addition, created snags increased in value for birds through their first decade (88% had cavities). Because snags created by topping last long and are readily used by birds, they should be considered a management option to improve avian habitat in managed forests.

We used harvested, stochastic population models for grizzly bears (Ursus arctos) and polar bears (U. maritimus) to illustrate the propensity for male-biased harvesting to reduce mean male age and numbers of sexually mature males for species with relatively low reproductive potential. We compared our results with those obtained from caribou (Rangifer tarandus), an annually reproducing species with relatively high reproductive potential. Differences in the rate at which mean ages and numbers of sexually mature males were reduced by harvesting was a function of differences in species life history of species, but also the extent to which young animals were protected from hunting. For example, the length of each species' reproductive cycle (we modeled 1 year for caribou, 2 years for bears) determined the degree to which sex-biased harvest was also age-biased. Proportionately more young bears were protected from harvest than young caribou due to the multiannual, rather than annual, parental care afforded young bears (we assumed all females with accompanying offspring were invulnerable to harvest). This additional age-bias in the hunt served to direct offtake toward adult males; consequently, as male selectivity in the kill increased, mean ages of bears declined at rates that were higher than for caribou. For species with low reproductive potential, we believe there is a real possibility that persistence probabilities may be overestimated if, after prolonged sex-selective harvest, lack of sexually mature males in the population impairs fecundity. We encourage further development of population models that incorporate potentially negative, hunting-induced impacts on reproduction. In particular, we support the development of models that link the mean age of males or frequency of adult males in a population to the rate at which females are successfully mated.

Recording ultrasonic echolocation calls of bats using bat-detectors is often used for wide-scale monitoring in studies on bat management and conservation. In Europe, the most important legal instrument for bat conservation is the Habitat Directive (43/92/EEC), which defines various levels of species (and habitat) protection for different bat species and/or genera. Thus for most management needs, the usefulness of bat-monitoring techniques depends on the possibility to determine to species/genus. We compared the discrimination performances of 4 statistical methods applied to identify bat species from their ultrasonic echolocation calls. In 3 different areas of northern Italy, we made recordings of 20 species of bat (60% of those occurring in Italy), 17 from the family Vespertilionidae and 3 from Rhinolophidae. Calls of bats identified to species level from morphological and genetic characters were time-expanded and recorded on release. We measured 7 variables from each call, and we developed classification models through both conventional tests (multiple discriminant analysis and cluster analysis) that were based on a classical statistical approach, and through 2 nonconventional classifiers (classification and regression trees, and neural networks) that relied on generalization and fuzzy reasoning. We compared the performance of the 4 techniques using the percentage of cases classified correctly in 5 classification trials at various taxonomic levels that were characterized by an increasingly difficult identification task: (1) family level (Rhinolophidae vs. Vespertilionidae), (2) species level within genus Rhinolophus, (3) genus level within Vespertilionidae, (4) species level within genus Myotis, and (5) all species. Multiple discriminant function analysis (DFA) correctly classified marginally more cases than artificial neural networks (ANN; 74–100% against 64–100%), especially at the species level (trial 4, species of genus Myotis; trial 5, all species). Both these techniques performed better than cluster analysis or classification and regression trees, the latter reaching only 56 and 41% in Myotis species and all species trials. Artificial neural networks do not yet seem to offer a major advantage over conventional multivariate methods (e.g., DFA) for identifying bat species from their ultrasonic echolocation calls.

Understanding how the distribution and abundance of food resources influence space use of organisms is an important element of successful conservation and recovery strategies for endangered species. We investigated interrelationships between space use, activity patterns, and food resources for lesser long-nosed bats (Leptonycteris curasoae), an endangered nectar-feeding bat, during an energetically demanding phase of its annual life cycle. We estimated the size of home ranges (95% kernel areas) and core use-areas (50% kernel areas) of bats and estimated density of their forage plant (Agave palmeri) in and near these use areas. Density (x̄± SE plants/ha) of flowering agaves within home ranges (3.6 ± 1.04) exceeded that which was available on the landscape (1.8 ± 0.36), indicating that bats selected areas with high food abundance. Although density of agaves within home ranges of bats differed in successive years (1998: 3.6 ± 1.04; 1999: 0.8 ± 0.15), sizes of home ranges and core use-areas of adult bats were similar between years, suggesting that the relationship between home-range size and density of food resources was mediated by other factors. Differences in activity budgets of bats between years suggest that bats altered their behavior in response to changes in food abundance, allocating more time to foraging the year fewer flowering plants were present. Consequently, reductions in agave density could increase energy demands of foraging bats and reduce the chances of successful recovery of lesser long-nosed bat populations.

Little is known about habitat selection of the giant panda (Ailuropoda melanoleuca), especially about the relationship between giant panda presence and bamboo and tree structures. We presented data on giant panda habitat use and selection in Foping Nature Reserve (NR), China. We used 1,066 radiotracking locations for 6 collared individuals to analyze giant panda habitat selection, and we used 110 plots to reveal the structure of giant panda habitat and its relationship with giant panda presence. We found that (1) giant pandas in Foping NR selected mostly 3 habitats: conifer forest, deciduous broadleaf forest, and Fargesia bamboo groves. (2) In winter, giant pandas selected deciduous broadleaf forest within elevations of 1,600 to 1,800 m with a south-facing slope of 10 to 20 degrees. In summer, giant pandas selected conifer forest within elevations of 2,400 to 2,600 m and a slope of 20 to 30 degrees. (3) Giant pandas selected the Bashaina fargesii bamboo area with short and dense culms in winter, while they selected the Fargesia qinlingensis bamboo area with a high coverage of tall and thick culms in summer. We concluded that giant pandas in Foping NR do select their preferred habitats. These findings may be used to guide the human activities in the reserve with consideration of giant panda habitat conditions.

Bait-station surveys are used by wildlife managers as an index to American black bear (Ursus americanus) population abundance, but the relationship is not well established. Hard mast surveys are similarly used to assess annual black bear food availability, which may affect mortality and natality rates. We used data collected in Great Smoky Mountains National Park (GSMNP) from 1989 to 2003 to determine whether changes in the bait-station index (ΔBSI) were associated with estimated rates of bear population growth (λ) and whether hard mast production was related to bear visitation to baits. We also evaluated whether hard mast production from previous years was related to λ. Estimates of λ were based on analysis of capture–recapture data with the Pradel temporal symmetry estimator. Using the Akaike's Information Criterion (AIC), our analysis revealed no direct relationship between Δ BSI and λ. A simulation analysis indicated that our data were adequate to detect a relationship had one existed. Model fit was marginally improved when we added total oak mast production of the previous year as an interaction term suggesting that the BSI was confounded with environmental variables. Consequently, the utility of the bait-station survey as a population monitoring technique is questionable at the spatial and temporal scales we studied. Mast survey data, however, were valuable covariates of λ. Population growth for a given year was negatively related to oak mast production 4 and 5 years prior. That finding supported our hypothesis that mast failures can trigger reproductive synchrony, which may not be evident from the trapped sample until years later.

Reported survival rates for yearling and subadult bears in hunted black bear (Ursus americanus) populations in North America are scarce. We estimated survival rates of yearling and subadult black bears from a hunted population in western Virginia during 1999–2002. We captured 307 individual yearling and subadult bears on 2 study sites, and we attached radiotransmitters to 54 (34M:20F) 1-year-old, 52 (23M:29F) 2-year-old, and 35 (8M:27F) 3-year-old black bears. We used the known fate model in program MARK to estimate annual, nonhunting, and hunting season survival for radiomarked bears of each age and sex class. Additionally, we used mark–recapture data in the recaptures only, dead recoveries, and Burnham's combined models within program MARK to estimate survival for each age and sex class. One-, 2-, and 3-year-old female survivorship was 0.87 (95% CI 0.78–0.92), 1-year-old male survivorship was 0.32 (95% CI 0.20–0.47), and 2- and 3-year-old male survivorship was 0.59 (95% CI 0.47 s– 0.71) from the Burnham's combined model. Survival rates for 1-year-old females (χ² = 6.20, P = 0.01) and 2-year-old females (χ² = 7.74, P = 0.01) were higher than males in each age category, respectively. Hunter harvest accounted for 98% of all subadult bear mortality during our study. Low yearling and subadult male survival is not likely a cause for alarm due to the importance of adult female survival to population growth and the promiscuous mating system in black bear populations.

We studied the seasonal movement patterns and dispersal of coyotes (Canis latrans) in the Bear River Mountains of northern Utah and southern Idaho to determine whether coyotes in this montane region exhibit an altitudinal migration on a seasonal basis. We used 3 locational parameters to assess whether a seasonal altitudinal migration was evident, including overlap in seasonal activity areas, distance between harmonic mean centers of activity, and seasonal differences in mean elevations of locations. Winter and summer activity areas of every mature coyote overlapped, with mean distances between harmonic centers of seasonal activity of 1.5 km (range = 0.4–3.3 km). Conversely, there was no overlap between summer and winter activity areas of any subadult coyotes, with mean distances between their harmonic seasonal centers of activity of 35.8 km (range = 16.7–68.4 km). Significant changes in elevation of seasonal locations were not evident for any sex or age group. We conclude that the movement of subadult coyotes in the Bear River Range was part of typical dispersal behavior and was not motivated by seasonal change, with such wandering generally ceasing during the coyotes' second year of age. We also conclude that adult coyotes utilized similar areas in summer as in winter, with no evidence of seasonal movements between mountain and locations at lower elevations.

Gray wolves (Canis lupus) in upper Michigan, USA, have been monitored since 1991 when breeding activity in mainland Michigan was documented for the first time since 1954. Based on winter track counts, the mean annual rate of increase in abundance was 19% from 1995 to 2002, with the population reaching an estimated 278 animals in 2002. Our objectives were to (1) increase the efficiency of wolf management in Michigan by evaluating alternative and less extensive sampling approaches for population estimation, and (2) evaluate habitat for wolves based on occupancy after a decade of recovery. For the first analysis, we created 22 discrete sampling units that cover upper Michigan, and we evaluated abundance estimates based on various sampling plans using known distribution and populations from the 2000–2002 winter track surveys. We evaluated each plan based on the precision, bias, and confidence interval coverage. A random sampling plan with regression estimator returned the most precise estimates, but a stratified sampling plan, using low, medium, and high wolf density strata had the greatest precision at lowest effort. For the habitat evaluation, we compared white-tailed (Odocoileus virginianus) deer density and road density between wolf pack locations from 1995 to 2001 to random locations outside of the current wolf range. We estimated white-tailed deer density by a spatial interpolation of pellet group counts. Our resource selection function indicated that probability of wolf occupation of an area was positively correlated with deer density, and it was relatively constant for road densities <0.4 km/km² but declined sharply at higher road densities. For areas habitable by wolves in upper Michigan, we predict a road density threshold of 0.7 km/km² and a deer density threshold of approximately 2.3–5.8 deer/km². We believe that these results will aid managers who need to estimate wolf abundance and predict wolf distribution.

We investigated the effects of thinning young (35- to 45-yr-old) Douglas-fir (Pseudotsuga menziesii) forests on density, survival, body mass, movements, and diets of northern flying squirrels (Glaucomys sabrinus) in the northern coast range of Oregon. We used a repeated measures, randomized block design with 3 treatments (control, moderate thinning, and heavy thinning) and 4 replicates to study diets and population characteristics from 1994–1997. Densities of flying squirrels were variable in space and time, but they were positively correlated to biomass and frequency of fungal sporocarps, suggesting they were responding to food resources rather than forest structure. Fungal sporocarps comprised a major portion of the squirrel's diet, and other vegetative material made up the remainder of the diet. Several fungal genera including Gautieria, Geopora, Hymenogaster, Hysterangium, Melanogaster, and Rhizopogon were found more frequently in diets than on the trapping grids and therefore appeared to be selected by the squirrels. Flying squirrel movements were negatively correlated with the frequency of occurrence of fungal sporocarps at trap stations, suggesting that squirrels traveled greater distances to find fungal sporocarps where these food items were more sparsely distributed. We hypothesized that flying squirrel densities would be relatively low in these young, structurally simple forests; however, densities on some of the grids were >1.5 squirrels/ha, which was comparable to densities described for the species in late-successional forests. Our results indicated that commercial thinning did not have measurable short-term effects on density, survival, or body mass of flying squirrels.

We studied the impact of proximity to human concentrations, hikers, and field vehicles on mountain gazelles (Gazella gazella gazella) space-use patterns, flight distance, and visibility in the southern coastal plain of Israel. We collected data on gazelle behavior and human disturbance from fixed observation sites, drive counts, and pellet counts. The density of pellets was positively correlated with the distance to human concentrations, and the flight distance was positively correlated with human disturbance level, suggesting mountain gazelle space use and flight distance were affected by human disturbance. Gazelles were less visible in the more disturbed areas. Our findings provide a framework for conservation measures such as determining the size of buffer zones and where and when enforcement efforts should take place to keep mountain gazelle populations viable in spite of the ecological impacts of human encroachment on mountain gazelle habitat.

Prey species are thought to select habitats to obtain necessary resources while also avoiding predation. We examined whether habitat selection by elk (Cervus elaphus) changed following the reintroduction of wolves (Canis lupus) into Yellowstone National Park in 1995. Using conditional fixed-effects logistic regression to build habitat-selection models, we compared seasonal habitat selection by elk based on weekly elk radiolocations taken in 1985–1990 (without wolves) and 2000–2002 (with wolves). Fire-related habitat changes and climate likely interacted with wolf avoidance in shaping habitat selection by elk. In summer, when wolf activity was centered around dens and rendezvous sites, elk apparently avoided wolves by selecting higher elevations, less open habitat, more burned forest, and, in areas of high wolf density, steeper slopes than they had before wolf reintroduction. In winter, elk did not spatially separate themselves from wolves. Compared to the pre-wolf period, elk selected more open habitats in winter after wolf reintroduction, but did not change their selection of snow water equivalents (SWE) or slope. Elk appear to select habitats that allow them to avoid wolves during summer, but they may rely on other behavioral antipredator strategies, such as grouping, in winter. This study provides evidence that wolves can alter seasonal elk distribution and habitat selection, and demonstrates how the return of wolves to Yellowstone restores important ecosystem processes.

We studied microhabitat use by black-faced impala in different herd types during the rut in the cold dry seasons of 2001 and 2002 in the Etosha National Park, Namibia. We investigated whether black-faced impala select feeding sites consistently for their microhabitat characteristics in 2 vegetation types, Karstveld and Tamboti Woodland. We also investigated intra-population differences in microhabitat use between herds of different types. In both habitats, sites used by impala for feeding were more likely to be in the shade, within 2 m of the edges of wooded areas and grassy clearings, with high visibility at 1 m height, and with lower grass swords than nearby nonfeeding sites. In Karstveld, feeding sites of impala were also located closer to the nearest shrub than were nonfeeding sites. A degree of fine-scale sexual segregation in microhabitat use was demonstrated, but it was not consistent across habitats. Incorporating these trends in the microhabitat use of black-faced impala into management decisions should maximize the success of small populations released at selected off-park sites.

Knowledge of Yellowstone bison (Bison bison) parturition patterns allows managers to refine risk assessments and manage to reduce the potential for transmission of brucellosis between bison and cattle. We used historical (1941) and contemporary (1989–2002) weights and morphometric measurements of Yellowstone bison fetuses to describe fetal growth and to predict timing and synchrony of parturition. Our method was supported by agreement between our predicted parturition pattern and observed birth dates for bison that were taken in to captivity while pregnant. The distribution of parturition dates in Yellowstone bison is generally right-skewed with a majority of births in April and May and few births in the following months. Predicted timing of parturition was consistently earlier for bison of Yellowstone's northern herd than central herd. The predicted median parturition date for northern herd bison in the historical period was 3 to 12 days earlier than for 2 years in the contemporary period, respectively. Median predicted birth dates and birthing synchrony differed within herds and years in the contemporary period. For a single year of paired data, the predicted median birth date for northern herd bison was 14 days earlier than for central herd bison. This difference is coincident with an earlier onset of spring plant growth on the northern range. Our findings permit refinement of the timing of separation between Yellowstone bison and cattle intended to reduce the probability of transmission of brucellosis from bison to cattle.