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Evaluating population responses to management is a crucial component of successful conservation programs. Models predicting population growth under different management scenarios can provide key insights into the efficacy of specific management actions both in reversing population decline and in maintaining recovered populations. Bald eagle (Haliaeetus leucocephalus) conservation in the United States has seen many successes over the last 50 years, yet the extent to which the bald eagle population has recovered in Arizona, an important population within the Southwest region, remains an area of debate. Estimates of the species' population trend and an evaluation of ongoing nest‐level management practices are needed to inform management decisions. We developed a Bayesian integrated population model (IPM) and population viability analysis (PVA) using a 36‐year dataset to assess Arizona bald eagle population dynamics and their underlying demographic rates under current and possible future management practices. We estimated that the population grew from 77 females in 1993 to 180 females in 2022, an average yearly increase of 3%. Breeding sites that had trained personnel (i.e., nestwatchers) stationed at active nests to mitigate human disturbance had a 28% higher reproductive output than nests without this protection. Uncertainty around population trends was high, but scenarios that continued the nestwatcher program were less likely to predict abundance declines than scenarios without nestwatchers. Here, the IPM‐PVA framework provides a useful tool both for estimating the effectiveness of past management actions and for exploring the management needs of a delisted population, highlighting that continued management action may be necessary to maintain population viability even after meeting certain recovery criteria. [ABSTRACT FROM AUTHOR]

We compared abundance patterns and developed resource selection models for imperilled native southwestern (USA) fishes in the presence and absence of Black Bass (Micropterus spp.) to evaluate how fishes alter their selection for habitats when sympatric with a nonnative piscivore. We collected data using snorkel surveys and in‐stream habitat sampling in Fossil Creek (AZ), upstream (native fish only) and downstream (native and nonnative fish) of a fish barrier. The abundance of all Roundtail Chub (Gila robusta), small (≤127 mm total length [TL]; vulnerable to predation) Sonora Sucker (Catostomus insignis) and Speckled Dace (Rhinichthys osculus) was significantly reduced, but the abundance of both small and large (>127 mm TL; invulnerable to predation) Desert Sucker (Catostomus clarkii) was similar in sampling reaches with and without Black Bass. When sympatric with Black Bass, small Roundtail Chub increased their selection for riffles by 2.57 times and small Desert Sucker reduce their selection for pools by 6.90 times while also selecting for faster flow velocity and finer substrates in lotic mesohabitats. Large native fishes altered selection least, notwithstanding an increased selection for canopy cover in sampling reaches with Black Bass. Observed shifts in resource selection are consistent with predator avoidance strategies. Our study highlights the behavioural consequences of nonnative piscivores on native fish communities and stresses the importance of maintaining lotic mesohabitats as potential refugia for vulnerable native fishes when nonnative piscivores are present. [ABSTRACT FROM AUTHOR]

Objective: The Red Shiner Cyprinella lutrensis is one of the most prolific and ecologically destructive invasive fish species in the southwestern United States. The production and release of YY individuals as Trojan sex chromosome carriers can theoretically eradicate invasive fish populations by eventually eliminating phenotypic females. Methods: The YY individuals are typically produced through hormonally induced sex reversals and selective breeding of subsequently feminized males. We tested three dosages of estradiol‐17β (E2)‐treated diets (50, 100, and 150 mg of E2 per kg of diet) administered to sexually immature Red Shiner for various durations to determine their effectiveness at feminizing Red Shiner cohorts. Survival, growth, and gonadal development were assessed for each treatment. Result: All E2 treatments had minimal, if any, detrimental effects on the growth and gonadal development of Red Shiner. The 50‐mg dosage lasting from 2 to 120 days posthatch achieved a 100% feminization rate while using the lowest amount of E2; therefore, this dosage and treatment interval are recommended when attempting Red Shiner feminization under these rearing conditions. Feminization of males allowed for the spawning of neofemales (FXY) with wild‐type males (MXY), which resulted in the first putative YY Red Shiner. The YY verification crosses (n = 20) resulted in predominately male offspring (189 males/191 offspring) except for (1) an intersex individual from an MYY × FXX cross with two previtellogenic oocytes in its testis and (2) a single female that may have resulted from an inbred cross between an XY male and a YY female or from an unknown autosomal or environmental effect on sexual phenotype. Conclusion: More progeny tests with inbred and outbred crosses should be conducted to determine the prevalence of female offspring from YY individuals and how this may impact an eradication strategy featuring releases of YY Red Shiner. Impact statementThis research features the first production of Red Shiner with two Y sex chromosomes, which provides fisheries managers a new eradication strategy where releasing YY Red Shiner into an invasive population could theoretically skew the sex ratio toward 100% male, thus protecting the native fish that Red Shiner negatively impact. [ABSTRACT FROM AUTHOR]

Pumas (Puma concolor) are solitary large carnivores that exhibit high energetic investments while hunting prey that often take multiple days to consume. Therefore, pumas should behave in a way to maximize their energetic gains, including using caching, which is a behavior used by many mammal species to preserve and store food or to conceal it from conspecifics and scavengers to limit their losses. Yet pumas do not always cache their kills. In order to understand caching behavior, we used variables associated with the kills such as prey mass, search time, climate, and habitat to test 20 ecological models (representing four a priori hypotheses: food perishability, resource pulse, consumption time, and kleptoparasitism deterrence) in an information-theoretic approach of model selection to explore factors related to the caching behavior. Models were run with information from tracked radio-collared pumas in California over a 2.5-year period and identified a total of 352 kills. Overall, we documented pumas caching 61.5% of their kills, including 71.6% of Black-tailed Deer (Odocoileus hemionus columbianus), their primary prey in the study area. The model with a quadratic effect of adjusted mass of prey on puma caching probability had all of the empirical support (w = 1.00). Specifically, pumas were most likely to cache intermediate-sized prey, such as yearling and adult female deer, and also fed from cached kills for longer periods of time. Larger prey may be too large to easily cache, making it less energetically efficient—while small prey can often be consumed quickly enough to not require caching. This suggests that intermediate-sized prey may be the optimal size for caching, allowing a puma to feed for multiple days while not greatly increasing energetic output. The hypotheses we tested were not mutually exclusive and pumas caching their prey may occur for several reasons; nevertheless, our study demonstrated that pumas use caching to extend their foraging time and maximize energetic gains when preying on intermediate-sized prey. [ABSTRACT FROM AUTHOR]

The Red Shiner Cyprinella lutrensis is of increasing management interest as an invasive species that negatively impacts many native fishes throughout North America. Trojan sex chromosome (TSC)‐carrying individuals could theoretically control invasive fish populations by skewing the sex ratio to 100% male. The efficacy of TSC‐based control programs requires an understanding of a population's sex determination system, yet such information is lacking for Red Shiner. We used single‐digest restriction site‐associated DNA sequencing to discover sex‐linked single‐nucleotide polymorphisms (SNPs), and we conducted a series of breeding experiments to uncover the sex determination system. All candidate sex‐linked SNPs that fit our selection criteria exhibited a pattern of male heterogamety. We developed two sex‐identification (sex‐ID) marker assays, XY_248 and XY_170, which showed phenotype–genotype concordance scores of 77.00% and 84.35%, respectively. These sex‐ID markers exhibited relatively high phenotype–genotype concordance in females (XY_248 = 96.30%; XY_170 = 98.61%), which allowed for selective breeding of phenotypically feminized genetic males. We observed a 3:1 male : female sex ratio in spawns from feminized males crossed with wild‐type males, indicative of a male heterogametic sex determination system (i.e., XY male/XX female). The discovery of a male heterogametic sex determination system, in combination with our two markers, increases the likelihood of developing an effective TSC eradication strategy for invasive Red Shiner populations. [ABSTRACT FROM AUTHOR]

Translocation is increasingly used to move animals of conservation concern away from sites where habitat will be destroyed (mitigation translocation), but outcomes have rarely been adequately monitored, particularly for amphibians. We used radiotelemetry monitoring to assess survival and movement of 23 experimentally translocated, adult Gopher Frogs (Lithobates capito) at a recipient site in north-central Florida, USA. Although posttranslocation monitoring was our primary goal, we also compared our results with those of 24 nontranslocated frogs that were monitored in three previous efforts, conducted at different locations and times. For both translocated and nontranslocated frogs, movement was the most important predictor of mortality, with translocated frogs having a significantly higher probability of movement and higher mortality during the first month following release. However, there was no effect of translocation on survival after controlling for probability of movement because movement was dangerous for both translocated and nontranslocated frogs. Movement by translocated frogs was likely a behavioral response to the translocation experience, whereas movement by nontranslocated frogs was associated with breeding pond visitation, which was not observed within the translocated group. Survival was high for both groups once they settled into underground refugia and movement declined. Despite the comparatively high mortality of translocated frogs immediately following release, more than half survived to the end of monitoring and remained in the vicinity of the release site, meeting an early benchmark of translocation success. [ABSTRACT FROM AUTHOR]

Range‐wide species conservation efforts are facilitated by spatially explicit estimates of habitat suitability. However, species‐environment relationships often vary geographically and models assuming geographically constant relationships may result in misleading inferences. We present the first range‐wide habitat suitability model (HSM) for the federally threatened eastern indigo snake (Drymarchon couperi) as a case study illustrating an approach to account for known latitudinal variation in habitat associations. Specifically, we modeled habitat suitability using interactive relationships between minimum winter temperature and several a priori environmental covariates and compared our results to those from models assuming geographically constant relationships. We found that multi‐scale models including interactive effects with winter temperature outperformed single‐scale models and models not including interactive effects with winter temperature. Our top‐ranked model had suitable range‐wide predictive performance and identified numerous large (i.e., ≥1000 ha) potential habitat patches throughout the indigo snake range. Predictive performance was greatest in southern Georgia and northern Florida likely reflecting more restrictive indigo snake habitat associations in these regions. This study illustrates how modeling interactive effects between temperature and environmental covariates can improve the performance of HSMs across geographically varying environmental gradients. [ABSTRACT FROM AUTHOR]

Species-specific conservation is important for maintaining the integrity of ecological communities but is dependent on sufficiently understanding multiple aspects of a species' ecology. Species-specific data are commonly lacking for species in geographic areas with little research and species perceived to have insufficient charisma or economic importance. Despite their widespread distribution across central and North America and status as a furbearing mammal, little is known about the ecology of Grey Foxes Urocyon cinereoargenteus compared to other species of furbearing mammals. To understand what is known about this species, especially factors affecting population dynamics, we performed a systematic review of the scientific literature. We found 234 studies about Grey Foxes, with studies increasing substantially over time but with geographic gaps in the Great Plains and most of Mexico and central America. Most studies we reviewed examined relative abundance or occupancy (n= 35), habitat associations (n= 30), primarily as part of larger mammalian community studies, or spatiotemporal effects of other mammalian carnivores (n= 19), predominately Coyote Canis latrans. Grey Foxes were primarily forest-associated although associations with specific forest communities or anthropogenically disturbed habitats varied among studies. Multiple studies across ecoregions reported this fox as among both the most- and least-abundant mammalian carnivore. The inter-specific effects of Coyote were often, but not exclusively, negative and were likely mediated by landscape composition and human development. Importantly, very few studies examined population-effects of coyotes on Grey Foxes. Studies of population trends, demographics, and space use of Grey Foxes were comparatively rare and small inter- and intra-study sample sizes limited our ability to infer broader patterns. We suggest multiple avenues for future research to better understand the population status of this species throughout their range. [ABSTRACT FROM AUTHOR]

Landscape features can strongly influence gene flow and the strength and direction of these effects may vary across spatial scales. However, few studies have evaluated methodological approaches for selecting spatial scales in landscape genetics analyses, in part because of computational challenges associated with optimizing landscape resistance surfaces (LRS). We used the federally threatened eastern indigo snake (Drymarchon couperi) in central Florida as a case study with which to compare the importance of landscape features and their scales of effect in influencing gene flow. We used genetic algorithms (ResistanceGA) to empirically optimize LRS using categorical land cover surfaces, multiscale resource selection surfaces (RSS), and four combinations of landscape covariates measured at multiple spatial scales (multisurface multiscale LRS). We compared LRS where scale was selected using pseudo‐ and full optimization. Multisurface multiscale LRS received more empirical support than LRS optimized from categorical land cover surfaces or RSS. Multiscale LRS with scale selected using full optimization generally outperformed those with scale selected using pseudo‐optimization. Multiscale LRS with large spatial scales (1200–1800 m) received the most empirical support. Our results highlight the importance of considering landscape features across multiple spatial scales in landscape genetic analyses, particularly broad scales relative to species movement potential. Different effects of scale on home range‐level movements and dispersal could explain weak associations between habitat suitability and gene flow in other studies. Our results also demonstrate the importance of large tracts of undeveloped upland habitat with heterogenous vegetation communities and low urbanization for promoting indigo snake connectivity. [ABSTRACT FROM AUTHOR]

While most carnivore populations are declining worldwide, some species are successfully living in human‐modified landscapes. For example, coyotes (Canis latrans) have expanded their range across North America and into many urban areas making it important to understand factors influencing broad‐scale patterns of occurrence. We used citizen science data in the form of coyote observations by archery deer hunters from throughout the state of Illinois to evaluate factors affecting coyote detection and occupancy. Our statewide participant‐level occupancy estimate (0.63) was 58% greater than our naïve occupancy estimate (0.40) while detection probability was <0.25, highlighting the importance of using modeling frameworks that account for imperfect detection when modeling occupancy of cryptic species with low detection rates. Time period (AM/PM) had the largest effect on detection of coyotes, with detections greater in the AM. The number of hours hunted (analogous to effort) also impacted coyote detection, with more hours hunted increasing coyote detections. In contrast, none of the landscape covariates examined had strong effects on coyote occupancy. While coyote ubiquity and generalist habitat use may at least partially explain our results, we suspect it also is because the landscape covariates were measured at the county level, as more precise participant location data were unavailable, whereas participants effectively surveyed a much smaller area. Since scale affects the strength and direction of species‐habitat relationships, this scale mismatch is likely an important limitation when using many sources of citizen scientist observations to infer species‐habitat relationships for widespread generalist species when precise participant location data are unavailable. [ABSTRACT FROM AUTHOR]

Context: Translocation is a widely used non-lethal tool to mitigate human–wildlife conflicts, particularly for carnivores. Multiple intrinsic and extrinsic factors may influence translocation success, yet the influence of release-site landscape context on the success of translocations of wildlife involved in nuisance behaviour is poorly understood. Moreover, few studies of translocated wildlife involved in nuisance behaviour have provided estimates of translocation success under different scenarios. Aims: We evaluated the role of intrinsic (age, sex) and extrinsic (translocation distance, landscape composition) features on translocation success of American black bears (Ursus americanus) involved in nuisance behaviour and provide spatially explicit predictions of success under different scenarios. Methods: We analysed data from 1462 translocations of 1293 bears in Wisconsin, USA, from 1979 to 2016 and evaluated two measures of translocation success: repeated nuisance behaviour and probability of returning to a previous capture location. Key results: Translocation distances ranged from 2 to 235 km (mean = 57 km). Repeated nuisance behaviour was recorded following 13.2% of translocation events (192 of 1457) and was not significantly affected by translocation distance. Bears repeated nuisance behaviour and were recaptured at their previous captures site (i.e. returned) after 64% of translocation events (114 of 178). Return probability decreased with an increasing translocation distance, and yearling bears were less likely to return than were adults. The proportions of agriculture and forest within 75 km and 100 km respectively, of the release site had positive and negative effects on return probability. Conclusions: Mangers can use bear characteristics and landscape context to improve translocation success. For example, achieving a 10% predicted probability of return would require translocation distances of 49–60 km for yearlings in low-agriculture and high-forest landscapes. In contrast, estimated return probability for adults was ≥38% across all translocation distances (0–124 km) and almost all landscape contexts. Implications: Our results emphasise the importance of considering the effects of landscape conditions for developing spatially explicit guidelines for maximising translocation success. We evaluated the influence of translocation distance, sex, age and landscape context on translocation success of American black bear (Ursus americanus) involved in nuisance behaviour, by using 37 years of data from Wisconsin, USA. Repeated nuisance behaviour following translocation events was rare (192 of 1457 events) and increasing translocation distance reduced the probability of bears being recaptured at their capture site (i.e. returning). Landscape context also influenced the probability of returning, which allowed us to estimate age-, sex- and landscape-specific return probabilities for given translocation distances, which can help managers increase translocation success. Photograph by David Ruid. [ABSTRACT FROM AUTHOR]

Catch-per-unit-effort (CPUE) is often used to monitor wildlife populations and to develop statistical population models. Animals caught and released are often not included in CPUE metrics and their inclusion may create more accurate indices of abundance. We used 21 years of detailed harvest records for bobcat (Lynx rufus) in Wisconsin, U.S.A., to calculate CPUE and 'actual CPUE' (ACPUE; including animals caught and released) from bobcat hunters and trappers. We calibrated these metrics to an independent estimate of bobcat abundance and attempted to create simple but effective models to estimate CPUE and ACPUE using harvest success data (i.e., bobcats harvested/available permits). CPUE showed virtually no relationship with bobcat abundance across all years, but both CPUE and ACPUE had stronger, non-linear, and negative relationships with abundance during the periods when the population was decreasing. Annual harvest success strongly predicted composite ACPUE and CPUE from hunters and trappers and hunter ACPUE and CPUE but was a poorer predictor of trapper ACPUE and CPUE. The non-linear, and sometimes weak, relationships with bobcat abundance likely reflect the increasing selectivity of bobcat hunters for trophy animals. Studies calibrating per-unit-effort metrics against abundance should account for population trajectories and different harvest methods (e.g., hunting and trapping). Our results also highlight the potential for estimating per-unit-effort metrics from relatively simple and inexpensive data sources and we encourage additional research into the use of per-unit-effort metrics for population estimation. [ABSTRACT FROM AUTHOR]

Understanding the factors influencing the degree of spatial overlap among conspecifics is important for understanding multiple ecological processes. Compared to terrestrial carnivores, relatively little is known about the factors influencing conspecific spatial overlap in snakes, although across snake taxa there appears to be substantial variation in conspecific spatial overlap. In this study, we described conspecific spatial overlap of eastern indigo snakes (Drymarchon couperi) in peninsular Florida and examined how conspecific spatial overlap varied by sex and season (breeding season vs. non-breeding season). We calculated multiple indices of spatial overlap using 6- and 3-month utilization distributions (UD) of dyads of simultaneously adjacent telemetered snakes. We also measured conspecific UD density values at each telemetry fix and modeled the distribution of those values as a function of overlap type, sex, and season using generalized Pareto distributions. Home range overlap between males and females was significantly greater than overlap between individuals of the same sex and male home ranges often completely contained female home ranges. Male home ranges overlapped little during both seasons, whereas females had higher levels of overlap during the non-breeding season. The spatial patterns observed in our study are consistent with those seen in many mammalian carnivores, in which low male-male overlap and high inter-sexual overlap provides males with greater access to females. We encourage additional research on the influence of prey availability on conspecific spatial overlap in snakes as well as the behavioral mechanisms responsible for maintaining the low levels of overlap we observed. [ABSTRACT FROM AUTHOR]

Context. Despite the diversity of available home range estimators, no single method performs equally well in all circumstances. It is therefore important to understand how different estimators perform for data collected under diverse conditions. Kernel density estimation is a popular approach for home range estimation. While many studies have evaluated different kernel bandwidth selectors, few studies have compared different formulations of the bandwidth matrix using wildlife telemetry data. Additionally, few studies have compared the performance of kernel bandwidth selectors using VHF radio-telemetry data from small-bodied taxa. Aims. In this study, we used eight different combinations of bandwidth selectors and matrices to evaluate their ability to meet several criteria that could be potentially used to select a home range estimator. Methods. We used handheld VHF telemetry data from two species of snake displaying non-migratory and migratory movement patterns. We used subsampling to estimate each estimator's sensitivity to sampling duration and fix rate and compared home range size, the number of disjunct volume contours and the proportion of telemetry fixes not included in those contours among estimators. Key Results. We found marked differences among bandwidth selectors with regards to our criteria but comparatively little difference among bandwidth matrices for a given bandwidth selector. Least-squares cross-validation bandwidths exhibited near-universal convergence failure whereas likelihood cross-validation bandwidths showed high sensitivity to sampling duration and fix rate. The reference, plug-in and smoothed cross-validation bandwidths were more robust to variation in sampling intensity, with the former consistently producing the largest estimates of home range size. Conclusions. Our study illustrates the performance of multiple kernel bandwidth estimators for estimating home ranges with datasets typical of many small-bodied taxa. The reference and plug-in bandwidths with an unconstrained bandwidth matrix generally had the best performance. However, our study concurs with earlier studies indicating that no single home range estimator performs equally well in all circumstances. Implications. Although we did not find strong differences between bandwidth matrices, we encourage the use of unconstrained matrices because of their greater flexibility in smoothing data not parallel to the coordinate axes. We also encourage researchers to select an estimator suited to their study objectives and the life history of their study organism. The performance of many kernel home range estimators with handheld radio telemetry data from many small-bodied taxa remains largely unexplored. We evaluated multiple kernel home range estimators from two snake species and found that estimators varied in their performance relative to the five criteria we considered. Our study provides guidelines to help researchers choose a kernel home range estimator that best suits their data and study objectives. Photograph by Kevin Stohlgren. [ABSTRACT FROM AUTHOR]

The article discusses the factors affecting the accuracy of triangulated radio telemetry locations of eastern Indigo snakes (Drymarchon couperi). Topics discussed include use of multiple metrics to evaluate triangulation accuracy, precision of beacon tests on triangulation accuracy, and correlation between estimated distance and ellipse area.