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Yellowstone National Park, USA, is a popular tourist destination with sympatric populations of grizzly bears (Ursus arctos) and American black bears (U. americanus). It receives >4 million recreational visits annually, and bear–human interactions are common. Many visitors are concerned about the risks of recreating in bear habitats, and wildlife managers are interested in knowing the risk of bear attack to inform safety messaging, reduce the frequency of bear attacks, and/or to address concerns regarding reintroduction of grizzly bears. To address those objectives, we analyzed 45 years (1979–2023) of recreational use statistics and bear attack data to estimate the risk of injury by bears while visitors are engaged in different recreational activities, including front-country recreation, overnight camping in roadside campgrounds and backcountry campsites, and backcountry hiking and horseback riding on overnight trips. We used generalized linear models to estimate the effects of these different types of use and of bear species on the rate of bear-inflicted human injury in the park. We found overall rates of injury were low (∼1/3.6 million visits caused by grizzlies and ∼1/23.2 million visits caused by black bears) and have decreased concurrently with increasing park visitation. Risk of injury varied by activity type and bear species involved. Users of vehicle-accessible campgrounds had a ∼98% lower rate of bear-inflicted injury than those in backcountry campsites. There was a marginally significant (P H 0.088) effect of species on the rate of injury to overnight users (stock riders and backpackers combined) with the rate of injury caused by grizzly bears being ∼5× that of black bears. When considering all use types combined, grizzly bears caused a ∼6.5× higher rate of injury than black bears did. Backcountry hikers are most at risk of injury from grizzly bears. Educational efforts should focus on activity types most at risk and emphasize science-based strategies for reducing surprise encounters. [ABSTRACT FROM AUTHOR]

American black bear (Ursus americanus) populations are increasing throughout much of North America. Use of multiple harvest methods, including hunting over bait, is intended to increase harvest success rates to meet harvest and population management objectives. However, black bear population growth can be influenced by food availability, and some speculate the use of bait may inadvertently increase bear abundance through food resource supplementation. We collected hair from black bears captured from 2005–2019 and a selection of potential food items, including those used as bait from 3 study areas in Maine, USA, with different levels of human influence. We used stable isotope analysis of the black bear hair and food item samples to evaluate the contribution of different identified food groups to the diet of individual bears. We found no evidence that greater contribution of human food resources, including bait, increased the number of cubs per litter for reproductive females or that human foods comprised a greater part of the diet in years when natural food resources were less abundant. Approximately 69% of black bear harvest occurred over bait. We found the probability of reproductive‐age females to be harvested increased with average representation of human foods with high carbon enrichment (including bait) in their diet, but the relationship was weak, likely because of sampling constraints. Additionally, the probability of being harvested was greater in years when natural food resources were scarce. We conclude that bait is not available on the landscape in large enough amounts or for a sufficient amount of time in Maine to substantially influence female reproduction. Our results indicate hunting over bait is an effective tool in a state that is attempting to maintain a stable bear population via harvest, and dispels conjecture that hunting over bait may increase cub production and offset the intention of harvest. [ABSTRACT FROM AUTHOR]

Although previously close to extirpation in the southeastern United States, American black bear (Ursus americanus) abundance and distribution have increased with habitat management and harvest regulation. The north Georgia black bear population, the most abundant and widely distributed in the state, is currently being exposed to pressures from increasing anthropogenic disturbances, such as recreation and vehicle traffic. We evaluated the effects of environmental factors and anthropogenic activity on habitat use of black bears within a wildlife management area open to public recreation. We used detection/non‐detection data from camera surveys conducted at 448 locations from April to December 2023 to fit hierarchical single‐species occupancy models. Black bear detection was best explained by Julian date, its quadratic effect, and weekly human activity index. Detection increased through the spring, peaked in June, and declined throughout late summer and fall. In contrast to detection, occupancy was not affected by seasonal differences in black bear activity. Occupancy increased with increasing elevation, distance to water, and distance to high‐use recreation areas. The spatial distribution of food resources likely contributed to the observed black bear occupancy pattern related to elevation and distance to water, while human disturbance in the study area also influenced black bear occupancy. Thus, our results suggest that in a landscape open to public recreation, black bear occupancy was driven by a combination of environmental and anthropogenic factors. Identifying patterns of occupancy at a scale typical of management provides important information for managing black bear populations throughout the large, connected network of national forests in the Appalachian region. [ABSTRACT FROM AUTHOR]

Live capture is an important tool for wildlife research, conservation, and management as it allows for insight into movement, behavior, demographics, diet, and health of wildlife populations. Live capture is also used for conservation translocations or to remove animals from human‐wildlife conflict situations. Improving trapping efficiency is beneficial for ethical considerations of wildlife handling, human safety, and the best use of limited resources. American black bears (Ursus americanus) are often captured using traps. Culvert‐ and box‐style traps are frequently transported using a trailer, and some are affixed to trailers, elevating the trap from the ground. Traps can be set on the ground or on trailers to reduce the set‐up and take‐down times. Although trap elements such as length, height, and visibility can influence trapping efficiency, it is unknown whether trailer presence influences capture success. We assessed the influence of single‐axle trailer presence on capture success of trapping black bears in northeastern Alberta, Canada, during spring 2022 and 2023. We compared capture success between the 2 methods and the influence of trailer presence on age and sex class. Sixty traps were set for a total of 472 trap‐nights resulting in 133 captures of 80 individual bears. Traps set with trailers present required, on average, 1.6 times more trap‐nights per capture (4.9) than those set without trailers (3.1). When only considering new captures, traps with trailers present required 1.9 times more trap‐nights to capture a bear, at 8.5 trap‐nights/capture for traps on trailers and 4.5 trap‐nights/capture when trailers were absent. Trailer presence reduced the success of overall and initial bear captures but did not influence recapture success or the proportion of captured bear age and sex classes. We conclude that wildlife researchers and managers should consider improving trap efficiency of black bears by removing traps from trailers. [ABSTRACT FROM AUTHOR]

Safe and effective chemical immobilization is a necessary component of large carnivore management and research, but laws regulating controlled substances can limit the use of many drugs by non‐veterinary personnel. NalMed‐A (40 mg/mL nalbuphine HCl, 10 mg/mL medetomidine HCl, 10 mg/mL azaperone tartrate) is a non‐controlled drug combination used to immobilize a number of free‐ranging species, but there are limited published reports of its usage by non‐veterinary personnel when immobilizing American black bears (Ursus americanus) and mountain lions (Puma concolor). Additionally, there are some safety concerns regarding anecdotal reports of spontaneous arousals occurring in large carnivores immobilized with NalMed‐A. We performed a retrospective analysis of capture forms for free‐ranging black bears (n = 34) and mountain lions (n = 7) immobilized with NalMed‐A by non‐veterinary personnel across Wyoming, USA, in 2017 and 2019–2024. Induction (x̅ ± SE) was 10.74 ± 1.16 minutes for black bears (n = 34) and 7.14 ± 1.60 for mountain lions (n = 7). Reversal was 14.21 ± 1.51 minutes for black bears (n = 28) and 10.00 ± 1.26 minutes for mountain lions (n = 5). We used non‐parametric tests (Kruskal‐Wallis, Wilcoxon rank sum) and odds ratios to examine the effect of certain parameters on induction times, redoses, and spontaneous arousals in black bears. Median induction time for black bears injected in their hind leg or rump was greater than for black bears injected in their shoulder (n = 34, W = 79.5, P = 0.045). Six black bears (18%) experienced spontaneous arousals. We recommend avoiding the hind leg and rump for dart placement in bears, and using hobbles and a muzzle for large carnivores when using NalMed‐A in a free‐ranging setting because of the risk of spontaneous arousals. [ABSTRACT FROM AUTHOR]

The American black bear (Ursus americanus) population on the Bruce Peninsula in southern Ontario, Canada, is small (∼300 bears), genetically isolated from the closest bears in other parts of Ontario because of geography and urban development, and it is at risk because of habitat loss. The Bruce Peninsula is underlain by dolostone, and soils over much of the Peninsula are shallow. The bedrock is karstic with extensive networks of rock fissures and underground drainage systems created by solutional processes. During the nondenning season bears select dense mixed forest and dense deciduous forest stands. From May 1998 to February 2004, we documented the habitat requirements of denning black bears on the Bruce Peninsula and described the characteristics of winter dens in this unique substrate. Thirteen of 30 (43%) dens were located in dense mixed forests, 12 of 30 (40%) were located in dense coniferous forests, and 4 of 30 (13%) were located in dense deciduous forests. Eighty-one percent of dens (25 of 31) were within rock crevices often >2 m deep and ending in a subsurface chamber. Of the remaining dens, 3 were excavated, 2 were under brush piles, and 1 was under a large boulder on a steep talus slope. Twenty-one of 29 dens were located with potential sanctuary trees (>30 cm diameter at breast height) within 30 m of the den. Population viability analysis determined the most effective management action that would ensure persistence of black bears on the Peninsula to be conserving habitat outside of Bruce Peninsula National Park. The importance of dense mixed and dense coniferous stands for denning shown in this study emphasizes that point. [ABSTRACT FROM AUTHOR]

In North America, polar bears (Ursus maritimus), grizzly bears (U. arctos), and American black bears (U. americanus) occasionally injure or kill humans. Although bear-inflicted human injuries are uncommon, they generate media attention that can lead to fear and unreasonable perceptions of the risk of bear attacks. Information on the behavioral responses of grizzly and black bears during interactions with people can provide a factual basis regarding the risks associated with recreating in bear habitats and assist land managers in developing and prioritizing bear safety messages. To address those objectives, we collected 17,171 reports of grizzly and black bear reaction behavior during interactions with people in Yellowstone National Park, USA, between 1991 and 2022. We used Bayesian Multinomial Logistic Regression models to examine the odds of attack, agitation and/or warning, flight, or curious behavioral reactions versus neutral responses in bear–human interactions. We found that reaction behavior depended on both the species involved and the location of the interaction. In developed areas and along roadsides, neutral responses were most likely for both species. On front-country trails, odds of curious or flee reactions were greater than neutral responses for both species. The odds of agitation and/or warning reactions from grizzlies were also greater in this setting. In backcountry campsites, there were marginally higher odds of black bears attacking; whereas, grizzlies had marginally higher odds of attacking during off-trail backcountry interactions. Although bear attacks were uncommon in all locations, grizzlies were ∼3.9× more likely than black bears to injure people in backcountry areas. Bear interactions with people were generally predictable; grizzly and black bears exhibited neutral behaviors or fled during most interactions. Curious approaches, agitation and/or warning behaviors, physical contact, and attacks were uncommon. Safety messages encouraging calm, confident responses during bear–human interactions are warranted, and may have better efficacy than those that generate fear and apprehension. [ABSTRACT FROM AUTHOR]

The present case report aims to describe a postmortem finding of a colloid goiter, without obvious clinical signs of endocrine disease in a 30-year-old American black bear (Ursus americanus) from the “Zoo” in the city of Sofia, Bulgaria. A clinical examination due to a bad general condition was performed under anesthesia and a computed tomography was conducted. After the established irreversible spondylarthrosis changes the bear was euthanized. Postmortem, the thyroid gland was pathologically examined and typical findings for a colloid goiter were observed. Hibernating mammals such as the American black bear have been shown to enter a state of physiological hypothyroidism during hibernation. Hormonal signals from the thyroid gland have been suggested to be a key mediator of hibernation. From the presented case could be assumed that the captive life conditions and the prolonged life of the zoo bears may affect the function of their thyroid gland.

The moose (Alces alces; mooz in Anishinaabemowin, Ojibwe language will follow scientific names) is a vital subsistence food source to Anishinabe people of the midwestern United States and has recently declined in Minnesota, USA, with poor calf survival as a contributing factor. Predation is the primary cause of moose calf mortality and we explored whether calf predation rates could be reduced through management of a single predator in a multi‐predator system. Thus, we examined predation rates and causes of calf mortality before (2013–2015) and during (2016–2018) implementation of a spring black bear (Ursus americanus; makwa) harvest season, using baits to attract black bears, on the Grand Portage Indian Reservation, Minnesota, where black bears and gray wolves (Canis lupus; ma'iinganag) are the primary predators of moose calves. We validated our early study findings for the 5 years following the initial study with intermittent spring bear hunting seasons, from 2019–2023. The spring bear hunt was canceled because of a pandemic lockdown in 2020, resumed 2021, and was closed in 2022 and 2023. Black bear harvest prior to adding a spring bear hunting season was 0.038 bears harvested/km2 from 2012–2015, whereas after initiating a spring hunting season (2016–2018) it was 17% higher at 0.046 bears/km2. We observed significantly lower bear predation (by 68%) in association with spring bear management and no compensatory change in the level of wolf predation. The validation years strengthened our findings that spring bear hunting seasons reduce moose calf predation rates, with an overall 68% lower proportion of bear predation on moose calves in the years when spring bear hunts were held. Mean proportion of calf predation attributed to bears was 4.9 times higher (30% vs. 6%) in the years when a spring bear hunt was not held. Despite an increasing wolf density during the study period, we did not observe a compensatory increase in wolf predation during spring bear hunt years. The results of this work suggest that the addition of a spring bear hunt, during a time when moose calves are most vulnerable to bear predation, has the potential to increase moose calf survival even in the presence of wolves. [ABSTRACT FROM AUTHOR]

Simple Summary: This case report highlights two wild juvenile American black bears that were admitted to a rehabilitation facility but were euthanized due to severe immobility and joint laxity. Known musculoskeletal diseases of young bears are usually caused by trauma in the wild, or potentially rickets (a form of malnutrition) if raised in captivity. However, Case 1 was diagnosed with abnormal cartilage development (chondrodysplasia), likely of genetic origin, and Case 2 had osteoporosis and unidentified collagen abnormalities which are both unique to the current literature. With growing black bear populations, and increasing wildlife–human interface, we advise wildlife biologists and veterinarians to monitor and evaluate similar cases to help us further understand these uncommon diseases. Severe musculoskeletal disease characterized by marked joint laxity was the cause of euthanasia in two wild juvenile American black bears (Ursus americanus) admitted to a rehabilitation facility in eastern Tennessee in 2023. Previously, almost all reported musculoskeletal diseases in this population were of traumatic etiology, even in malnourished yearlings. Case 1 was an orphaned 11-month-old male cub exhibiting disproportionate dwarfism, progressive immobility, and joint laxity. Necropsy findings suggested either chondrodysplasia or rickets, and imaging findings supported a skeletal dysplasia. Case 2 was a 14-month-old emaciated male yearling exhibiting joint laxity and immobility. Necropsy findings showed osteoporosis and serous atrophy of fat, and imaging findings were inconsistent with a skeletal dysplasia. Both cases were clinically inconsistent with rickets based on normal calcium, phosphorous, and parathyroid hormone concentrations; however, Case 1 had hypovitaminosis D (9 nmol/L) compared to healthy juvenile black bears. We hypothesize that Case 1 had a genetic chondrodysplasia while the osteoporosis of Case 2 was due to chronic malnutrition. The goal of this case report is to inform wildlife agencies and facilities to monitor for similar, non-trauma-related debilitating musculoskeletal disease in free-ranging bears and evaluate cases that allow us to further understand the disease processes involved. [ABSTRACT FROM AUTHOR]

Use of dens during winter is an important strategy for American black bears (Ursus americanus) for both energy conservation and reproduction; and occupancy of suitable den sites has implications for reproductive fitness. Denning strategies may change as a result of changing climatic conditions and habitat loss. Black bears occupy arid environments in the eastern Sierra Nevada and the western ranges of the Great Basin Ecosystem. Our objectives were to identify: (1) which physical characteristics of habitat influenced selection of den sites at multiple spatial scales and (2) which environmental factors influenced timing of entrance and exit of dens by females and males. We evaluated selection of den sites by black bears at three spatial scales (300, 1000, and 4000 m) from 2011 to 2022. Terrain ruggedness was important for selection of den sites at all spatial scales. Within a 300‐m buffer from the den, bears selected den sites with rugged terrain, lower horizontal visibility, and greater canopy cover, resulting in more concealment and protection than that of the surrounding environment. Within 1000‐ and 4000‐m buffers around each den, bears selected den sites with rugged terrain, northern aspects, and steep slopes. At the 4000‐m scale, we observed interactions between sex with slope and distance to roads; females selected den sites on steeper slopes and closer to roads than did males. Females remained in the dens longer than males by entering earlier in the autumn and exiting later in the spring. Male bears exited their dens earlier with increasing consecutive days above freezing temperatures, but that relationship was weak for females. Knowing what characteristics are important for selection of den sites, and influence timing of denning, will be important for understanding how shifting climatic patterns will affect bears, particularly in arid environments that may be prone to wider fluctuations in climatic drivers of denning in the future. [ABSTRACT FROM AUTHOR]

Wildlife space use is a key component to consider when determining effective conservation and management practices. Home range size and resource selection can vary temporally and spatially depending on mortality risks in the area and access to food resources. Lands used for coal mining can contain unique mortality risks and food resources for American black bears (Ursus americanus) relative to surrounding landscapes due to hunting restrictions, vegetation planted as part of the reclamation process, and other anthropogenic food resources. We examined the influence of mining sites on resource selection of female black bears in southern West Virginia, USA, during 2007 and 2008. We estimated home range size with Brownian Bridge movement models and evaluated variation in home range size with mixed‐effects linear regression. We evaluated resource selection with mixed‐effects Poisson point process models. On mine sites, the mean 95% home range for female black bears was 1,996 ha (SD = 2,633) in the autumn and 544 ha (SD = 238) in the spring, and on non‐mine sites the mean 95% home range was 1,926 ha (SD = 1,292) in the autumn and 771 ha (SD = 480) in the spring. Our resource selection model indicated black bears used nonhunting zones associated with mine lands much greater than their availability, and that black bears in mine areas disproportionately used areas in close proximity to anthropogenic structures. Interannual variation in home range size was likely associated with mast conditions, because smaller home ranges were associated with high mast production. Our data suggest black bears may be using non‐hunting zones within mine lands as refugia from hunting and are using anthropogenic food sources available at refuse sites on mine lands, which may increase regional black bear populations in areas with high mining activity. [ABSTRACT FROM AUTHOR]

It has been suggested that the American black bear (Ursus americanus) may be responsible for a significant number of purported sightings of an alleged unknown species of hominid in North America. Previous analyses have identified a correlation between 'sasquatch' or 'bigfoot' sightings and black bear populations in the Pacific Northwest using ecological niche models and simple models of expected animal sightings. The present study expands the analysis to the entire US and Canada by modelling sasquatch sightings and bear populations in each state/province while adjusting for human population and forest area in a generalized linear model. Sasquatch sightings were statistically significantly associated with bear populations such that, on the average, every 1000 bear increase in the bear population is associated with a 4% (95% CI: 1–7%) increase in sasquatch sightings. Thus, as black bear populations increase, sasquatch sightings are expected to increase. On average, across all states and provinces in 2006, after controlling for human population and forest area, there were approximately 5000 bears per sasquatch sighting. Based on statistical considerations, it is likely that many supposed sasquatch are really misidentified known forms. If bigfoot is there, it could be a bear. [ABSTRACT FROM AUTHOR]

Anthropogenic pressure, such as urbanization and habitat loss, can wield many effects on wildlife that radiate through ecosystems. Large carnivores tend to experience these effects more severely than other species, diminishing their viability and altering ecosystem function by suppressing their role as an apex predator. Yet opportunistic carnivores that rely on an omnivorous diet can sometimes take advantage of anthropogenic food and improve their fitness prospects. We quantified the effect of phenotypic and ecological factors on female body mass of the American black bear (Ursus americanus) in New Jersey, USA. Habitat and reliable mast crops in New Jersey keep adult female black bear body mass and reproduction higher than many parts of the United States, and historically, female black bears in the mid‐Atlantic states tend to be larger than in other parts of their range. We used data collected from den surveys (n = 317) in northern New Jersey from 1984 to 2019 to examine the shared roles of climate, anthropogenic pressure (human food subsidies, harvest), habitat composition and configuration, natural food availability (hard mast production), and bear characteristics (age, history of human–black bear conflict) on female black bear body mass using generalized linear mixed models. Adult female body mass was heaviest with increased availability of cultivated crop and within low‐intensity developed land covers, suggesting anthropogenic food subsidies found in these 2 land cover types are contributing to female overall body mass. A history of conflict with humans explained heavier females, and a quadratic effect of age on body mass supported a senescent decline in adult female body mass later in life. Our results suggest that access to specific land cover types (i.e., crops, low‐intensity developments) that provide a diversity of food (e.g., corn, soft and hard mast) and support low human densities, explains female black bear body mass in a fragmented landscape. [ABSTRACT FROM AUTHOR]

The prevalence, intensity, or outcome of interference competition and interspecific killing between predominantly solitary species operating on large spatial scales is challenging to document or test. Here, we present a detailed account of inter‐ and intraspecific interactions from contemporaneous GPS location data and in‐field investigation. In June 2018, a GPS‐collared female cougar (Puma concolor) maintained strong site fidelity for a period of 19 days, indicative of parturition behavior and establishment of a nursery site. In early July 2018, three GPS‐collared black bears (Ursus americanus) arrived at the nursery site, after which the female cougar abandoned the site. Site investigation showed that one or more bears predated an unknown number of cougar kittens. The evidence supports ecological theory suggesting that body size, mass, or group number is an important predictor of outcome. Our observation provides an example of bears potentially making risk–reward trade‐offs by eliminating a potential competitor that at the same time provisions carrion as critical food resources. These real‐time inter‐ and intraspecies competitive interactions as documented using GPS collars allow for greater insight into individual fitness and community‐level effects. [ABSTRACT FROM AUTHOR]

Rehabilitation and release back to the wild of orphaned American black bear (Ursus americanus) cubs is a wildlife management option used across North America. We reviewed the literature and surveyed wildlife managers and biologists within North America from August 2022 through March 2023 to gather information on their policies and practices regarding rehabilitation and release of orphaned black bear cubs. We define cubs as bears <1 year old but note that most releases happen when the animals are yearlings, typically 12–18 months of age. The literature suggests that when rehabilitation follows science-based protocols, it is a feasible management option, and rehabilitated cubs may survive at rates similar to those of their wild counterparts, die of similar causes, and generally have low rates of conflicts with humans. Repeatedly mentioned within both the literature and survey results was the importance of minimizing human contact and selecting appropriate release sites that consider habitat, food availability, proximity to humans, and the age structure, genetics, and density of black bears in the release area. We received 99 responses from 63 different jurisdictions. Rehabilitation of orphaned black bear cubs was allowed in 72.5% of surveyed jurisdictions with a breeding black bear population. In 82.3% of jurisdictions, a government agency was responsible for selecting release sites. The most common causes identified by our survey for cubs being orphaned were vehicle collisions (50 of 63 responses) and removal of mothers because of conflict behavior (35 of 63 responses). Almost all (96.9%) jurisdictions required rehabilitation centers to be licensed. On average, over the past 5 years (2018–2022), most (70.8%) jurisdictions rehabilitated <25 orphaned cubs. Lack of reliable and suitable rehabilitation centers following strict, science-based protocols was a frequently mentioned challenge, as was managing public perceptions and expectations. Despite these challenges, most (61%) survey respondents said rehabilitation of orphaned black bear cubs was either somewhat or very successful. [ABSTRACT FROM AUTHOR]

From 2014-2019, 8 juvenile black bears (Ursus americanus) from different geographic regions were presented to the California Department of Fish and Wildlife because of emaciation, alopecia, and exfoliative dermatitis that resulted in death or euthanasia. Autopsy and histopathology revealed that all 8 bears had generalized hyperkeratotic dermatitis, folliculitis, and furunculosis. Skin structures were heavily colonized by fungal hyphae and arthrospores; fungal cultures of skin from 7 bears yielded Trichophyton equinum, a zoophilic dermatophyte reported only rarely in non-equid species. Additional skin conditions included mites (5), ticks (2), and coagulase-negative Staphylococcus sp. infections (2). No other causes of morbidity or mortality were identified. Molecular comparisons performed at the University of Texas Fungal Reference Laboratory determined that all isolates produced identical banding patterns, potentially representing a clonal population. Dermatophytosis is commonly localized and limited to the stratum corneum of the epidermis and hair follicles. Generalized disease with dermal involvement is rare in immunocompetent individuals; illness, malnutrition, age, or immunosuppression may increase susceptibility. Underlying causes for the severe disease impact in these bears were not evident after physical or postmortem examination. The mechanism by which bears from different geographic locations had severe, T. equinum-associated dermatophytosis from a potentially clonal dermatophyte could not be explained and warrants further investigation.

Hibernation is a period of metabolic suppression utilized by many small and large mammal species to survive during winter periods. As the underlying cellular and molecular mechanisms remain incompletely understood, our study aimed to determine whether skeletal muscle myosin and its metabolic efficiency undergo alterations during hibernation to optimize energy utilization. We isolated muscle fibers from small hibernators, Ictidomys tridecemlineatus and Eliomys quercinus and larger hibernators, Ursus arctos and Ursus americanus. We then conducted loaded Mant-ATP chase experiments alongside X-ray diffraction to measure resting myosin dynamics and its ATP demand. In parallel, we performed multiple proteomics analyses. Our results showed a preservation of myosin structure in U. arctos and U. americanus during hibernation, whilst in I. tridecemlineatus and E. quercinus, changes in myosin metabolic states during torpor unexpectedly led to higher levels in energy expenditure of type II, fast-twitch muscle fibers at ambient lab temperatures (20 °C). Upon repeating loaded Mant-ATP chase experiments at 8 °C (near the body temperature of torpid animals), we found that myosin ATP consumption in type II muscle fibers was reduced by 77–107% during torpor compared to active periods. Additionally, we observed Myh2 hyper-phosphorylation during torpor in I. tridecemilineatus, which was predicted to stabilize the myosin molecule. This may act as a potential molecular mechanism mitigating myosin-associated increases in skeletal muscle energy expenditure during periods of torpor in response to cold exposure. Altogether, we demonstrate that resting myosin is altered in hibernating mammals, contributing to significant changes to the ATP consumption of skeletal muscle. Additionally, we observe that it is further altered in response to cold exposure and highlight myosin as a potentially contributor to skeletal muscle non-shivering thermogenesis.

Abstract The prevalence, intensity, or outcome of interference competition and interspecific killing between predominantly solitary species operating on large spatial scales is challenging to document or test. Here, we present a detailed account of inter‐ and intraspecific interactions from contemporaneous GPS location data and in‐field investigation. In June 2018, a GPS‐collared female cougar (Puma concolor) maintained strong site fidelity for a period of 19 days, indicative of parturition behavior and establishment of a nursery site. In early July 2018, three GPS‐collared black bears (Ursus americanus) arrived at the nursery site, after which the female cougar abandoned the site. Site investigation showed that one or more bears predated an unknown number of cougar kittens. The evidence supports ecological theory suggesting that body size, mass, or group number is an important predictor of outcome. Our observation provides an example of bears potentially making risk–reward trade‐offs by eliminating a potential competitor that at the same time provisions carrion as critical food resources. These real‐time inter‐ and intraspecies competitive interactions as documented using GPS collars allow for greater insight into individual fitness and community‐level effects.

In 2001 and 2002, 52 elk (Cervus canadensis; 21 males, 31 females), originally obtained from Elk Island National Park, Alberta, Canada, were transported and released into Cataloochee Valley in the northeastern portion of Great Smoky Mountains National Park (GRSM, Park), North Carolina, USA. The annual population growth rate (λ) was negative (0.996, 95% CI = 0.945–1.047) and predation by black bears (Ursus americanus) on elk calves was identified as an important determinant of population growth. From 2006 to 2008, 49 bears from the primary elk calving area (i.e., Cataloochee Valley) were trapped and translocated about 70 km to the southwestern portion of the Park just prior to elk calving. Per capita recruitment (i.e., the number of calves produced per adult female that survive to 1 year of age) increased from 0.306 prior to bear translocation (2001–2005) to 0.544 during years when bears were translocated (2006–2008) and λ increased to 1.118 (95% CI = 1.096–1.140). Our objective was to determine whether per capita calf recruitment rates after bear removal (2009–2019) at Cataloochee were similar to the higher rates estimated during bear removal (i.e., long‐term response) or if they returned to rates before bear removal (i.e., short‐term response), and how those rates compared with recruitment from portions of our study area where bears were not relocated. We documented 419 potential elk calving events and monitored 129 yearling and adult elk from 2001 to 2019. Known‐fate models based on radio‐telemetry and observational data supported calf recruitment returning to pre‐2006 levels at Cataloochee (short‐term response); recruitment of Cataloochee elk before and after bear relocation was lower (0.184) than during bear relocation (0.492). Recruitment rates of elk outside the removal area during the bear relocation period (0.478) were similar to before and after rates (0.420). In the Cataloochee Valley, cause‐specific annual calf mortality rates due to predation by bears were 0.319 before, 0.120 during, and 0.306 after bear relocation. In contrast, the cause‐specific annual mortality rate of calves in areas where bears were not relocated was 0.033 after the bear relocation period, with no bear predation on calves before or during bear relocation. The mean annual population growth rate for all monitored elk was 1.062 (95% CI = 0.979–1.140) after bear relocation based on the recruitment and survival data. Even though the effects of bear removal were temporary, the relocations were effective in achieving a short‐term increase in elk recruitment, which was important for the reintroduction program given that the elk population was small and vulnerable to extirpation. [ABSTRACT FROM AUTHOR]

Understanding the role of recruitment in population dynamics of white‐tailed deer (Odocoileus virginianus) is important for management. In the central Appalachian Mountains, deer are part of a largely forested ecosystem that supports 3 carnivore species thought to be capable of influencing white‐tailed deer recruitment: black bears (Urus americanus), coyotes (Canis latrans), and bobcats (Lynx rufus). Yet little is known about predation, how other environmental factors influence recruitment, or the importance of neonate survival to white‐tailed deer population performance in the region. Our objectives were to identify causes of mortality for neonates, analyze effects of landscape attributes on survival of neonates, estimate survival rates for neonates and adult female white‐tailed deer, and to model population growth trends based on current vital rates and hypothetical harvest and neonate survival scenarios. During 2019–2020, we captured 57 neonate deer in Bath County, Virginia, USA, by monitoring 38 pregnant females equipped with global positioning system collars and vaginal implant transmitters and by conducting transect searches for recently born neonates. We observed 37 neonate mortalities and identified cause of death using field and genetic evidence. Mortalities included 28 predation events and 9 deaths from other causes (e.g., abandonment, malnutrition, disease). Black bears accounted for 48.6% of neonate mortalities, and 64.2% of predation events (n = 18), followed by bobcats (n = 5) and coyotes (n = 3). Annual survival for adult female deer was 0.871 and neonate survival to 12 weeks old was 0.310. Elevation was a significant predictor of neonate survival; mortality risk increased 20% for every 100‐m increase in elevation. Models of annual population growth using observed vital rates predicted an increasing population (λ = 1.10). A 10% increase in female harvest would still result in a potential population increase of 2% (λ = 1.02), but a 20% increase in harvest rate would result in a potential 7% decline (λ = 0.93). Neonate survival was higher near fertile valley bottoms and lower along forested ridges characterized by shallow, infertile soils and limited edge or early successional forests. While predation, largely influenced by black bears, was the leading cause of neonate mortality and contributed to low neonate survival, we observed little evidence of population decline, and suggest there is opportunity for a modest increase in harvest of female deer. [ABSTRACT FROM AUTHOR]

American black (Ursus americanus) and grizzly bears (U. arctos) are sympatric throughout much of the grizzly bear's range, but information on how they share the landscape is lacking because distribution usually is not estimated simultaneously for both species. Here we analyze DNA data from noninvasively collected hair (using hair snags and rub trees) in a spatially explicit capture–recapture framework to study factors affecting the distribution of density for both black and grizzly bears in south Jasper National Park, Alberta, Canada, in 2014. Ninety-three black bears and 32 grizzly bears were detected. Black bears and grizzly bears showed different rates of detection for hair snags and rub trees, with hair snags being more effective in sampling both species. Female black bear density was greatest close to the town of Jasper, near roads, and in areas of higher amounts of closed canopy cover. Male black bear density was greatest at lower elevations with high canopy closure, and close to roads. Female grizzly bear density was greatest further from gravel roads, while male grizzly bear density was highest away from gravel roads and at medium canopy cover. We tested grizzly bears density as a predictor for black bear density and found that although habitat was the primary factor influencing black bear distribution, there was also a minor effect of grizzly bear density on male black bear density, and a slightly greater effect of grizzly bear density on female black bear density. The distribution of black bears within this study area puts them at a higher risk of conflict with humans. Our findings that grizzly bears prefer areas further from roads supports the use of habitat security thresholds to reduce human disturbance of grizzly bears. [ABSTRACT FROM AUTHOR]

Having reproducible and transparent science‐based processes in wildlife management ensures the integrity of decision making. These processes are particularly important when establishing harvest frameworks, as guiding information in the peer‐reviewed literature is limited. We provide an example using multiple data sets, whose products guided aspects of the development of a harvest framework for a population of recolonizing American black bears (Ursus americanus) in Missouri, USA. To characterize the spatial distribution of harvest, we used 10 years (2010–2019) of black bear global positioning system (GPS) location data and 30 years (1991–2020) of sightings data to assess spatial vulnerability to harvest as the intersection among information on bear occurrence, bear sightings, and hunter land‐use tendencies (i.e., the avoidance of steep slopes, large distances from roads). We then used the spatial vulnerability assessment, information on the distribution of public and private lands, and easily discernable boundaries (i.e., major highways, rivers) to suggest boundaries for bear management zones. Additionally, to identify the timing of harvest that would limit female harvest bias, we assessed the temporal vulnerability of harvest using sex‐based changes in average daily step lengths and monthly utilization distribution sizes during fall. Black bear occurrence and sighting propensity was greater in southwestern Missouri, and potential hunter land use appeared pervasive across the landscape given the lack of landscape features that would disincentivize use. Given the influence of black bear occurrence and sighting propensity, spatial harvest vulnerability diminished from southern and southeastern to central portions of Missouri, with areas north of the Missouri River not a part of the established black bear range. We consequently divided areas south of the Missouri River into 3 black bear management zones: a small southwestern zone with primarily private lands and high harvest vulnerability, a southeastern zone that encompassed considerable public lands and moderate amounts of vulnerability, and a central zone that was composed mainly of areas of low vulnerability. Temporally, males did not exhibit movement‐based changes, but females became less active after the first week of October and used 63.9% less area through fall. Based on movements rates of males and females, a hunting season after the first week of October could reduce the likelihood of females being harvested. Harvests from the black bear harvest season in 2021 suggest that the proportion of bears harvested in each zone was similar in distribution to the proportion of permits allocated across zones with no harvest sex bias, which was aligned with agency goals. Animal movement and space use data products can guide harvest framework decision‐making. [ABSTRACT FROM AUTHOR]

The long‐term effects of intensive forest harvest on sensitive demographic stages of the American black bear (Ursus americanus) have been often overlooked. Much of Maine, USA, is covered in forests that are hospitable to bears and commercial timber harvest. To investigate the potential effects of differing intensities of disturbance on black bears, and on females with cubs particularly, we designed a large‐scale natural experiment with 197 motion‐sensitive camera sites dispersed over representative forest stands in northern and central Maine. Using multi‐state occupancy models, we distinguished the overall trends in space use by females with young versus adult bears without young. Forest disturbance at large spatial scales was positively associated with the probability of use for both demographic groups and the availability of hardwood trees was an additional important factor for habitat use by females with young. Our study illustrates the use of motion‐sensitive cameras to monitor and understand habitat use by distinct life‐history stages of animals living in human‐modified landscapes, and results indicate that managers can maintain black bear habitat in areas of active forest harvest by ensuring the availability of hardwood species. [ABSTRACT FROM AUTHOR]

The quality and availability of resources are known to influence spatial patterns of animal density. In Yellowstone National Park, relationships between the availability of resources and the distribution of grizzly bears (Ursus arctos) have been explored but have yet to be examined in American black bears (Ursus americanus). We conducted non‐invasive genetic sampling during 2017–2018 (mid‐May to mid‐July) and applied spatially explicit capture‐recapture models to estimate density of black bears and examine associations with landscape features. In both years, density estimates were higher in forested vegetation communities, which provide food resources and thermal and security cover preferred by black bears, compared with non‐forested areas. In 2017, density also varied by sex, with female densities being higher than males. Based on our estimates, the northern range of Yellowstone National Park supports one of the highest densities of black bears (20 black bears/100 km2) in the northern Rocky Mountains (6–12 black bears/100 km2 in other regions). Given these high densities, black bears could influence other wildlife populations more than previously thought, such as through displacement of sympatric predators from kills. Our study provides the first spatially explicit estimates of density for black bears within an ecosystem that contains the majority of North America's large mammal species. Our density estimates provide a baseline that can be used for future research and management decisions of black bears, including efforts to reduce human–bear conflicts. [ABSTRACT FROM AUTHOR]

Immobilization kits including butorphanol-azaperone-medetomidine (BAM) and nalbuphine-azaperone-medetomidine can provide effective, safe, and easy-to-use protocols in bears. Nalbuphine-azaperone-medetomidine is not commercially available but may be useful for wildlife agencies because it does not contain controlled substances. This study directly compared BAM to nalbuphine-azaperone-medetomidine immobilization in 10 juvenile healthy black bears (10 mo old; four females, six males) undergoing prerelease examinations after rehabilitation. Bears were immobilized via remote delivery of 1 mL of BAM (n¼5) or nalbuphine-azaperone-medetomidine (n¼5) intramuscularly in the shoulder during December (randomized, blinded trial). Bears were intubated, monitored with an electrocardiogram, pulse oximeter, capnograph, noninvasive blood pressure cuff, and rectal thermometer, and underwent physical examination, sample collection, morphometrics, and ear-tag placement. Induction, physiologic, and recovery parameters were recorded, including arterial blood gas analysis. The anesthetic agents were antagonized with atipamezole and naltrexone. There were no differences between protocols in induction or recovery times. There were no differences between protocols in heart rate, respiratory rate, temperature, oxygen saturation, end-tidal CO2, mean arterial pressure, or blood gas analysis or any differences between male and female bears in any parameters. Bears were hypertensive and normoxemic with low oxygen saturation via pulse oximeter, but all recovered smoothly and were released within 2 h of recovery. This study supports that nalbuphineazaperone-medetomidine is clini-cally as safe and effective as BAM in American black bears. [ABSTRACT FROM AUTHOR]

Context. Road networks are related to two global problems: habitat loss and degradation, and the decline of biodiversity. Wildlife roadkill is one of the most obvious and immediate impacts of linear infrastructure that affects all vertebrate groups, and some species,such aslarge carnivores, are more susceptible to fragmentation by roads due to their wide-ranging movements and home ranges. Aims. Recently, black bear (Ursus americanus) sightings have increased in urban and suburban areas. The objectives of this study were: to identify and characterise road crossing sites used by black bears; to understand whether bears select specific landscape or road features for crossing; to compare crossing and roadkill sites; and to identify the most important variables in both groups to propose short-term mitigation strategies. Methods. For the analysis of crossing sites, black bear individuals were captured from 2014 to 2018 and released with a GPS collar. We also calculated the dynamic model of Brownian motion to identify the road crossing sites. We obtained collision records from field work and government agencies. We performed Firth’s penalisedlikelihood logistic regression models to identify the most important variables of highway or landscape in the probability of crossing or roadkill. Key results. We captured 15 black bear individuals (11 males and four females), seven of which crossed a road at least once. Most of the crossings occurred during the night, which explains the results of the regression model between crossing and roadkill sites because crossings are a function of the percentage of buses and urban use. We also found that the speed at roadkill sites is significantly higher than at crossing sites. Conclusions. This study contributed aspects necessary to understand the management of highways and reduce their impact on the black bear population in Mexico, such as the identification of priority mitigation sites. Systematic monitoring of roadkill in Mexico is required to propose specific mitigation sites that will benefit more vertebrate groups. Implications. The information generated in this research forms the basis of identification of optimal sites for strategies to mitigate the bear–road conflict and help the conservation of the species. [ABSTRACT FROM AUTHOR]

Investigating spatial patterns of animal occupancy and reproduction in peripheral populations can provide insight into factors that form species range boundaries. Following historical extirpation, American black bears (Ursus americanus) recolonized the western Great Basin in Nevada from the Sierra Nevada during the late 1900s. This range expansion, however, has not continued further into the Great Basin despite the presence of additional habitat. We aimed to quantify whether reduced reproduction toward the range edge contributes to this range boundary. We analyzed black bear detections from 100 camera traps deployed across black bear distribution in western Nevada using a multistate occupancy model that quantified the probability of occupancy and reproduction (i.e., female bears with cubs occupancy) in relation to changes in habitat type and habitat amount toward the range boundary. We detected a strong effect of habitat amount and habitat type on the probability of black bear occupancy and reproduction. At similar levels of landscape‐scale habitat amount (e.g., 50%), estimated probability of occupancy for adult bears in piñon‐juniper woodlands near the range boundary was 0.39, compared to ~1.0 in Sierra Nevada mixed‐conifer forest (i.e., core habitat). Furthermore, estimated probability of cub occupancy, conditional on adult bear occupancy, in landscapes with 50% habitat was 0.32 in Great Basin piñon‐juniper woodlands, compared to 0.92 in Sierra Nevada mixed‐conifer forest. Black bear range in the western Great Basin conforms to the center–periphery hypothesis, with piñon‐juniper woodland at the range edge supporting ecologically marginal habitat for the species compared to habitat in the Sierra Nevada. Further geographic expansion of black bears in the Great Basin may be limited by lower occupancy of reproducing females in piñon‐juniper woodland. Center–periphery range dynamics may be common in large carnivore species, as their dispersal ability allows them to colonize low‐quality habitat near range edges. [ABSTRACT FROM AUTHOR]

During the Late Pleistocene, major parts of North America were periodically covered by ice sheets. However, there are still questions about whether ice‐free refugia were present in the Alexander Archipelago along the Southeast (SE) Alaska coast during the last glacial maximum (LGM). Numerous subfossils have been recovered from caves in SE Alaska, including American black (Ursus americanus) and brown (U. arctos) bears, which today are found in the Alexander Archipelago but are genetically distinct from mainland bear populations. Hence, these bear species offer an ideal system to investigate long‐term occupation, potential refugial survival and lineage turnover. Here, we present genetic analyses based on 99 new complete mitochondrial genomes from ancient and modern brown and black bears spanning the last ~45,000 years. Black bears form two SE Alaskan subclades, one preglacial and another postglacial, that diverged >100,000 years ago. All postglacial ancient brown bears are closely related to modern brown bears in the archipelago, while a single preglacial brown bear is found in a distantly related clade. A hiatus in the bear subfossil record around the LGM and the deep split of their pre‐ and postglacial subclades fail to support a hypothesis of continuous occupancy in SE Alaska throughout the LGM for either species. Our results are consistent with an absence of refugia along the SE Alaska coast, but indicate that vegetation quickly expanded after deglaciation, allowing bears to recolonize the area after a short‐lived LGM peak. [ABSTRACT FROM AUTHOR]

Bear damage to western larch trees on intensively managed public and private forest lands of the Intermountain West continues to be a problem for forest managers. Bark stripping and subsequent cambium feeding by bears commences upon den emergence in the spring, when foraging options are most restrictive. Various damage reduction methods are often controversial (snaring, hunting, supplemental feeding), or do not always adequately resolve the problem (silvicultural strategies); hence, a need exists for the development of alternative nonlethal techniques to reduce damage. We tested the efficacy of three candidate repellents (Hot Sauce®, Tree Guard™, and grizzly bear feces) to reduce spring/summer bear damage to western larch trees on reforestation units in northern Idaho. Plots were laid out and treated in early June and examined for damage four months later. Thirty-four of 300 (11.3%) treated trees were damaged by black bears. Of the newly damaged trees, the highest damage rates were on the control plots: 15 of 75 (20%) trees. Damage levels to trees on treatment plots were 8-9.3%. Mean area of damage, or bark removal, on newly damaged trees only, was 452.8 cm2. Almost half (47%) of the bear-damaged trees were completely girdled. Chi-square contingency table analysis showed that the damage rate of treated trees was less than of control trees. No difference in mean surface area of damage was detected among treatments. Further testing is necessary to reveal the true potential of chemical repellents for reducing black bear damage to conifers in the spring. A wide array of chemicals should be evaluated for their potential.

Simple Summary: I trained an American black bear in human care to choose different response buttons when presented with an image of either a highly preferred or a less preferred food item. The bear learned to choose the appropriate response button when presented with the preferred food item at above chance levels and differentiated between the use of the buttons appropriately. However, she did not reach a high level of performance with the less preferred food item even after over 1000 trials, suggesting that performing a conditional discrimination on the basis of preferences may be challenging for black bears. However, the work presented here represents the first attempt to train a bear to indicate her relative preferences using something like a Likert scale commonly used with humans to indicate their preferences and could be a valuable welfare tool for animals in human care. Similar work with gorillas suggests that bears are as capable as great apes in learning such tasks and would also benefit from this type of technical enrichment. A preference scale for use by nonhuman animals would allow them to communicate their degree of liking for individual items rather than just relative preferences between pairs of items. It would also allow animals to report liking for images of objects that would be difficult to directly interact with (e.g., potential mates and habitat modifications). Such scales can easily be presented using touchscreen technology. Few zoos have used touchscreen technology for species other than nonhuman primates. I present a description of efforts taken to create such a scale for use with a single zoo-housed American black bear (Ursus americanus). Although the bear did not reach a high level of proficiency with assigning preferred and non-preferred food items to categorical responses of "like" and "dislike," she was able to learn how to use the like and dislike buttons differentially for a single preferred and less preferred food item and she selected the correct response button for the preferred item at above chance levels. These data contribute to our limited understanding of black bear cognition and suggest that conditional discriminations may be difficult for black bears. This finding can inform continued efforts to create a simpler tool for nonhumans to communicate their preferences to human caregivers in a more nuanced way than is currently possible. More generally, the current study contributes to the growing body of work supporting the use of touchscreen technology for providing enrichment to less studied species like bears. [ABSTRACT FROM AUTHOR]

In the first 2 decades of the twenty‐first century, American black bear (Ursus americanus) populations rebounded with range expansions into areas where the species was previously extirpated. While there are a number of factors that limit range expansion, habitat quality and availability are among the most important. Such factors may be particularly important in western Nevada, USA, at the transition zone of the Sierra Nevada and the Great Basin Desert. We deployed a multi‐faceted data collection system including motion‐sensitive cameras, noninvasive hair sampling and genotyping, and global positioning system (GPS) tracking. We analyzed data using spatial capture‐recapture to estimate population density and dynamic occupancy models to estimate habitat use. Black bear habitat use and density were substantially higher in the Sierra Nevada than the Great Basin Desert and had strong positive relationships with the presence of conifer land cover in the transition zone. The average black bear density was >4 times higher in the mixed‐conifer forests of the Sierra Nevada (12.4 bears/100 km2) than in desert mountain ranges with piñon (Pinus monophylla)‐juniper (Juniperus spp.) woodland (2.7 bears/100 km2). The low‐elevation shrub and grassland portions of the study area had even lower estimated black bear density (0.6 bears/100 km2) and probability of use (0.03, 95% CI = 0.00–0.09). Across these spatially variable configurations in black bear density, we estimated the population size to be 418 individuals (95% CI = 239–740). Declining density towards the range edge, coupled with a relatively stable range of black bears in Nevada observed since 2000, suggests that further species range expansion into the western Great Basin may be limited by habitat quality and availability. [ABSTRACT FROM AUTHOR]

Human–wildlife conflict can cause major declines in wildlife populations and pose a threat to human safety and livelihoods. Large carnivores are among the most conflict‐prone species because they range widely, eat human‐associated foods, and can pose a risk to human safety. Legal harvest of carnivores by licensed hunters is an attractive method to attempt to reduce conflict; however, there is mixed evidence for its effectiveness. We leveraged a unique management project in Ontario, Canada in which a new spring American black bear (Ursus americanus) hunting season was implemented in selected wildlife management units in addition to the existing fall season. We examined human–bear interactions and incidents before (2012 and 2013) and after (2014 and 2015) this implementation in treatment and control areas. Further, using data from 2004–2019, we examined the longer‐term patterns of human–bear interactions and incidents before and after this management project when a spring season was implemented throughout the entire province beginning in 2016. Harvest increased significantly upon the implementation of the spring season in selected units, but there was no concomitant reduction in interactions or incidents, and these were higher in areas with the new spring season relative to control areas. Human–bear interactions, incidents, and harvest were strongly related to the availability of natural foods in all analyses. Regulated, presumably sustainable harvest was ineffective at reducing human–bear interactions and incidents in the near‐term and might have increased both. Our results support a long history of research showing that natural food availability is a primary driver of human–wildlife conflict. Programs promoting coexistence between people and wildlife, including education, capacity building, and management of unnatural food sources are likely to be the most successful at reducing conflicts between people and bears. [ABSTRACT FROM AUTHOR]

Human-bear (Ursus spp.) interactions (HBI) commonly occur in residential areas throughout North America. Negative HBI can be alleviated by using bear-resistant garbage cans (BRC) and by securing other bear attractants (e.g., bird feeders). Since the early 2000s, human and Florida black bear (U. americanus floridanus) densities have increased substantially throughout Florida, USA, concurrently producing an increase in HBI. In central Florida, an area with high densities of humans and black bears, we surveyed 2 neighborhoods that occurred in an urban ordinance zone established in 2016 that required residents to secure anthropogenic food sources. Residents were supplied with BRC in 2017, and our surveys in 2017 and 2018 assessed the changes in HBI in the year before and after receiving BRC as well as the attitudes of residents toward ordinance measures and the perceived effectiveness of BRC. We found that a combination of preventive measures practiced by residents along with use of BRC effectively reduced HBI by 54%, especially bears eating garbage (reduced to 0%). Consequently, residents spent more time outdoors in their neighborhoods and experienced an elevated quality of life because fear of HBI lessened. We also analyzed public calls to the Florida Fish and Wildlife Conservation Commission concerning HBI. Public calls declined during the 5 years after the ordinance was established compared to 5 years prior. A reduction in HBI (especially conflicts) and public acceptance of using BRC is a long-term goal for management of black bears in Florida. [ABSTRACT FROM AUTHOR]

Animal tool use has been documented for a variety of wildlife, but few studies have evaluated tool use by bears. We used long-term video data to observe and classify behaviors of wild American black bears (Ursus americanus) in western Montana, USA, during 2012–2022. We present video-documentation of true and borderline tool use by multiple individuals. Six bears (4F:2M) picked up sticks from the bottom of a creek pool and then manipulated the sticks with their forepaws to scratch and/or rub themselves. In addition, one bear manipulated a tree sapling near a cage trap in an apparent attempt to reach hanging food. We identified several parent–offspring relationships among our small sample size of tool users, indicating that tool use behavior may have partially developed via social learning and/or genetic inheritance. Our findings build on the limited research on ursid tool use and demonstrate the value of long-term video data to document wild bear behavior. [ABSTRACT FROM AUTHOR]

Humans interact with wildlife regularly, mostly without conflict. Interactions between humans and bears, however, have a history of conflict. Using data from female black bears in two populations, we compared behaviors related to a series of hypotheses about habituation and food supplementation via research feeding. We livetrapped bears in the southern boreal forests and cove forests of the Pisgah National Forest, North Carolina, in barrel traps or modified leg-hold snares and outfitted them with very high frequency (VHF) transmitters, for 95 bear-years of data. In the southern boreal forests of Superior National Forest, Minnesota, we habituated bears and outfitted them with VHF collars supplemented with GPS units, for 42 bear-years. Some human residents of the Superior study area fed local black bears and we established a research feeding site. Bears in both populations avoided roads and habituated: Superior bears avoided houses where they were not fed; the study site for Pisgah bears (no habituation or feeding) had too few houses to test for avoidance. Bears in both populations gained weight faster during their active seasons when wild foods were abundant. Habituated, supplemented Superior bears averaged a smaller proportion of a day active, longer activity bouts, and less sinuous movements than did not-habituated or supplemented Pisgah bears. The bears in the two populations did not differ with respect to distances traveled per 2 h or mean lengths of activity bouts. The abundance of wild foods affected time active, distance traveled, and sinuosity of travel by not-habituated or supplemented Pisgah bears. Females in breeding condition in both populations were more active, had longer activity bouts, traveled further, and had more linear travel in spring and early summer while females with cubs pushed these activities into late summer and autumn. This timing pattern for bout length, distance moved, and sinuosity was less pronounced for habituated and research-fed Superior bears than for not-habituated or supplemented Pisgah bears. Thus, habituation to a small number of researchers appeared to not affect many behaviors of bears in our habituated and research-fed Superior population; research feeding appeared to affect some behaviors in a manner consistent with a food supply that had low annual variance. Because we have samples of one for each treatment (one site with habituation and feeding, one site without), our results do not establish that differences documented between the populations were caused by the differences in habituation and feeding. The effects of habituation, research feeding, or other forms of food supplementation on backcountry behaviors of black bears need broader testing across the range of black bears. [ABSTRACT FROM AUTHOR]

American black bears (Ursus americanus) require suitable den sites that provide security and cover to successfully survive the winter denning period. On Vancouver Island, British Columbia, Canada, black bears prefer to use cavities associated with large‐diameter hollow trees or structures derived from trees (i.e., cavities in or under logs, root boles and stumps) as den sites. Extensive harvesting of coastal forests has reduced the availability of natural den structures such that their supply may affect population sustainability. I attempted to develop new methods to address the declining supply of denning opportunities by creating and testing new den structures constructed in trees, stumps and from plastic. Between 2014–2021, I created or deployed and monitored 17 potential den structures in 2 study areas that were believed to have low den supply. I documented up to 51 visits by bears at each structure; every one of the video‐monitored structures was investigated at least 5 times. None of the plastic artificial den structures were used by bears, but an enhanced natural structure was used as a den over 4 consecutive winters. My work indicates that bears will find and investigate all natural or artificial denning structures in their environment, but artificial structures do not appear to be a viable method to mitigate losses of dens caused by forest harvesting. [ABSTRACT FROM AUTHOR]

Stable isotope analyses of hair have been used to estimate the consumption of human foods by American black bears (Ursus americanus). Consumption of human foods influences body mass and reproductive success of bears. However, the underlying factors that cause some bears to become conflict bears and resort to consuming human foods as a portion of their diet are not fully understood. We collected hair samples for stable isotope analysis from 51 black bears in Great Smoky Mountains National Park, Tennessee, USA in 2006. We used δ13C values of hairs to determine if the bears were consuming C3-based (natural foods) or C4-based (human foods) diets, and δ15N values, which increase with more meat in the diet, as a further indication of the consumption of human foods. Male bears with the heaviest tooth wear had a combination of higher δ15N and δ13C values, suggesting that they consume human foods to a greater extent than do other black bears. Based on our results, we hypothesize that tooth wear, and thus dental health, may play a role in the consumption of human foods by larger, male bears. [ABSTRACT FROM AUTHOR]

Tick abundance and diagnosed cases of tick-borne diseases have been increasing in the United States. American black bear (Ursus americanus) populations have also been increasing in the eastern United States. As a competent host of several species of ticks and a mammal capable of traveling long distances, the role of black bears as hosts for ticks requires further evaluation. Ectoparasite surveys were conducted on black bears in Pennsylvania to evaluate tick presence, abundance, spatial distribution, and association with Sarcoptes scabiei, the etiological agent of sarcoptic mange, on bears to better understand their role in tick ecology and to improve on-host surveillance techniques. Tick burden was evaluated using standard area sampling (10.16 × 10.16 cm squares) on pre-designated body regions on black bears from June 2018–December 2019. In total, 278 unique individual black bears were evaluated, with all ticks identified as Ixodes scapularis (n = 1976; 76.7% adults, 23.3% immatures). Tick presence differed by body region on bears, with the highest percentage of tick observations located on bear ears and muzzle. Ticks also partitioned on black bears by life-stage, with immature ticks primarily recorded on the lower extremities of bears and adult ticks primarily recorded on the front-quarters of bears. This includes the first known record of I. scapularis larvae parasitizing black bears, and observations of all three mobile life-stages concurrently parasitizing bears. Tick abundance was also statistically significant dependent on season, with the highest abundance of ticks recorded in spring and lowest abundance in fall. Adult ticks were less likely to be present on bears with mange. These data reveal the important role black bears may serve in tick ecology and dispersal as all three mobile life-stages of I. scapularis were found parasitizing a mammal capable of traveling far distances in a region with high numbers of Lyme disease cases.

Less than 30% of all species reintroductions have been successful and it is important that factors associated with success or failure be identified. Officials experimentally translocated 14 adult female American black bears (Ursus americanus) from Great Smoky Mountains National Park, North Carolina and Tennessee, USA, to Big South Fork National River and Recreation Area in the Cumberland Plateau of Kentucky and Tennessee, USA, in 1996–1997. Since that time, the reintroduced bear population has continued to expand in size and range so our study objective was to use spatially explicit capture‐recapture methods across a wide spatial extent to estimate bear population abundance and growth. We constructed 440 (223 in KY, 217 in TN) hair traps in our primary sampling area in 2019 arranged in clusters of 4–9 traps/cluster, which we augmented with data from 138 hair traps in a secondary sampling area in Tennessee collected in 2018. We extracted and genotyped DNA from hair samples to construct spatially explicit capture histories, using spatial covariates to model inhomogeneous densities. Population abundance estimates across our 36,035‐km2 study area were 411 males and 406 females excluding cubs. Based on an initial standing population of 18 adult and subadult bears, the mean annual growth rate (λ) from 1998 to 2019 was 1.199. The mean annual harvest rate in Kentucky from 2013 to 2019 was 5.1% and in Tennessee from 2014 to 2019 was 13.2%. Based on simulations, the hunting seasons reduced mean λ from 1.217 to 1.199, but growth was rapid despite harvest. Genetic diversity was retained, with similar expected heterozygosity as in the source population. The lack of conspecifics, highly productive habitat, and an initial age and sex distribution that was skewed toward the most fecund members of the population likely contributed to the rapid growth and high levels of gene retention in this bear population. [ABSTRACT FROM AUTHOR]

The phylogeography of the American black bear (Ursus americanus) is characterized by isolation into glacial refugia, followed by population expansion and genetic admixture. Anthropogenic activities, including overharvest, habitat loss, and transportation infrastructure, have also influenced their landscape genetic structure. We describe the genetic structure of the American black bear in the American Southwest and northern Mexico and investigate how prehistoric and contemporary forces shaped genetic structure and influenced gene flow. Using a suite of microsatellites and a sample of 550 bears, we identified 14 subpopulations organized hierarchically following the distribution of ecoregions and mountain ranges containing black bear habitat. The pattern of subdivision we observed is more likely a product of postglacial habitat fragmentation during the Pleistocene and Holocene, rather than a consequence of contemporary anthropogenic barriers to movement during the Anthropocene. We used linear mixed‐effects models to quantify the relationship between landscape resistance and genetic distance among individuals, which indicated that both isolation by resistance and geographic distance govern gene flow. Gene flow was highest among subpopulations occupying large tracts of contiguous habitat, was reduced among subpopulations in the Madrean Sky Island Archipelago, where montane habitat exists within a lowland matrix of arid lands, and was essentially nonexistent between two isolated subpopulations. We found significant asymmetric gene flow supporting the hypothesis that bears expanded northward from a Pleistocene refugium located in the American Southwest and northern Mexico and that major highways were not yet affecting gene flow. The potential vulnerability of the species to climate change, transportation infrastructure, and the US–Mexico border wall highlights conservation challenges and opportunities for binational collaboration. [ABSTRACT FROM AUTHOR]

Mange, a parasitic skin disease caused by various species of mites, is found in free-ranging wildlife populations and has been increasingly reported in American black bears (Ursus americanus) over the last decade in New York State (NYS), USA. Our goal was to describe the geographic, seasonal, and demographic factors associated with mange in this species in NYS. Our retrospective study used historic, opportunistic data from diagnostic necropsy records and visual sighting reports collected by the NYS Wildlife Health Program from 2009 to 2018. We used chi-square tests for independence and odds ratios to examine whether geographic location, year, season, sex, age, and reason for laboratory submission were associated with mange in bears. We used maps and seasonal analysis to investigate emerging patterns. We confirmed increased black bear mange reports in recent years. Necropsy data revealed more bears submitted to the laboratory because of mange, mainly caused by Sarcoptes scabiei; females were more likely than males to present with sarcoptic mange. We found that cases of mange in the Northern Zone were widely disseminated throughout the region, whereas cases in the Southern Zone were concentrated in two areas along the Pennsylvania border. Seasonally, mange cases showed peaks occurring in late spring to early summer and in fall. Our results were on the basis of available data; a comprehensive statewide surveillance program would be useful to better understand the apparent increase in mange and its potential impact on both the welfare of individual animals and the population of black bears in NYS. Additional research on the timing of transmission dynamics associated with females in winter dens may be helpful to wildlife managers to identify strategies to mitigate deleterious spread of the disease in black bears. [ABSTRACT FROM AUTHOR]

Information about how animal abundance varies across landscapes is needed to inform management action but is costly and time‐consuming to obtain; surveys of a single population distributed over a large area can take years to complete. Surveys employing small, spatially replicated sampling units improve efficiency, but statistical estimators rely on assumptions that constrain survey design or become less reasonable as larger areas are sampled. Efficient methods that avoid assumptions about similarity of detectability or density among replicates are therefore appealing. Using simulations and data from >3500 black bears sampled on 73 independent study areas in Ontario, Canada, we (1) quantified bias induced by unmodeled spatial heterogeneity in detectability and density; (2) evaluated novel, design‐based estimators of average density across replicate study areas; and (3) evaluated two estimators of the variance of average density across study areas: an analytic estimator that assumed an underlying homogeneous spatial Poisson point process for the distribution of animals' activity centers, and an empirical estimator of variance across study areas. In simulations where detectability varied in space, assuming spatially constant detectability yielded density estimates that were negatively biased by 20% to 30%; estimating local detectability and density from local data and treating study areas as independent, equal replicates when estimating average density across study areas using the design‐based estimator yielded unbiased estimates at local and landscape scales. Similarly, detectability of black bears varied among study areas and estimates of bear density at landscape scales were higher when no information was shared across study areas when estimating detectability. This approach also maximized precision (relative SEs of estimates of average black bear density ranged from 7% to 18%) and computational efficiency. In simulations, the analytic variance estimator was robust to threefold variation in local densities but the empirical estimator performed poorly. Conducting multiple, similar SECR surveys and treating them as independent replicates during analyses allowed us to efficiently estimate density at multiple scales and extents while avoiding biases caused by pooling spatially heterogeneous data. This approach enables researchers to address a wide range of ecological or management‐related questions and is applicable with most types of SECR data. [ABSTRACT FROM AUTHOR]

Camera or genetic data are increasingly used to estimate wildlife abundance and density. We integrated video camera data with genetic data over 7 years to estimate annual age‐structured apparent survival of American black bears (Ursus americanus). We identified 70 individuals through meticulous scrutiny of 7531 video captures, cross‐referenced with 721 genetic captures from hair samples concurrently collected from stations in view of cameras. We used the Cormack–Jolly–Seber model in Program Mark to estimate annual age‐structured apparent survival for yearling males, yearling females, 2+ year‐old males, and 2+ year‐old females. We manually calculated cub survival. We compared parameter estimates based on combined video and genetic data with those based on only genetic data. Combining video and genetic data provided a means to test video‐based identification accuracy, which was highest for females (97%–100%). Annual apparent survival was highest for yearling females (φ = 0.92, SE = 0.07), followed by 2+ year‐old females (φ = 0.88, SE = 0.05), 2+ year‐old males (φ = 0.84, SE = 0.06), and yearling males (φ = 0.80, SE = 0.14). Annual cub survival (φ = 0.86, SE = 0.07) was likely biased because we could not account for mortality that occurred in‐den through early spring. Annual apparent survival and recapture probabilities derived from only genetic data were lower than those derived from combined video and genetic data. Our finding that noninvasive data can be used to estimate annual age‐structured apparent survival of a species with relatively indistinct traits is broadly relevant to wildlife research and conservation. [ABSTRACT FROM AUTHOR]

American black bears (Ursus americanus) commonly habituate to human resources in regions of urban‐wildland interface, which frequently leads to human‐wildlife conflict. Monitoring bear densities is important to inform management, yet traditional density estimation methods may not be practical in such areas. Minimally or noninvasive genetic tools offer a potential solution, but the most common sampling method employs barbed‐wire hair snares and scented lure, which can pose dangers to people and pets. Fecal DNA, which is less invasive, has been used successfully for many species, but has not been commonly used for ursids in the United States. We conducted a pilot study from July–September 2018 to assess the feasibility of using fecal DNA in a spatial capture‐recapture analysis to estimate black bear density in the Lake Tahoe Basin in California, a region of high‐human density compared to other urban‐wildland interface localities in the United States, where bears pose significant nuisance problems. The use of fecal DNA allowed us to sample in both urban and wildland areas with minimal disturbance to the surrounding community. Based on 142 genotyped samples from 101 distinct individuals, we estimated an abundance of 0.84 bears/km2 (95% CI = 0.58–1.21 bears/km2), which was similar to a previous capture‐recapture estimate in the study area and represents one of the highest densities reported for black bears. More generally, our findings indicated that fecal DNA capture‐recapture approaches provide a feasible means of estimating black bear densities in areas where hair sampling may be impractical. [ABSTRACT FROM AUTHOR]

Ground‐based trapping can be the most practical approach for capturing American black bears (Ursus americanus) in remote portions of Alaska. During the summers of 2016–2018 we captured 106 black bears in a coastal portion of southcentral Alaska, USA, using bucket cable traps and Aldrich snare sets, 2 common foot snaring techniques. Despite widespread use, little research has focused on factors contributing to success and differences in safety for both foot snaring techniques. We compared trap engagement and success and found that bears engaged with bucket cable traps at a 31% (CL = 3–50%) lower rate than with Aldrich snare sets but once engaged were equally likely to be successfully snared. Prebaiting sites increased capture success 362% (CL = 21–1663%) but it was unclear if success improved when sites were prebaited multiple times. Regardless of trap type, bear engagement with sets were 194% higher (CL = 94–345%) during mid‐day hours (0800–1559) compared to crepuscular or nocturnal hours. We observed average injury scores of less than 11 points (out of 400 possible points) for both set types, consistent with the score given for minor lacerations. Both methods performed well within the recommended safety standards of the American Society of Mammalogists. [ABSTRACT FROM AUTHOR]

Aim: Decades of research on species distributions has revealed geographic variation in species‐environment relationships for a given species. That is, the way a species uses the local environment varies across geographic space. However, the drivers underlying this variation are contested and still largely unexplored. Niche traits that are conserved should reflect the evolutionary history of a species whereas more flexible ecological traits could vary at finer scales, reflecting local adaptation. Location: North America. Methods: We used mammal observations during a 5‐year period from the iNaturalist biodiversity database and a local ensemble modelling approach to explore spatial variation in American black bear (Ursus americanus) relationships with eight ecological correlates. We tested four biologically driven hypotheses to explain the patterns of local adaptation. We evaluated non‐stationarity in ecological relationships using a Stationarity Index and tested predictive performance using an independent, national‐level animal occurrence data set. Results: We documented considerable spatial non‐stationarity in all eight environmental relationships, with the greatest spatial variation occurring in bear's relationship to climatic factors. Notably, the greatest variation in environmental relationships tended to occur along the current boundaries of the species' range, potentially representing the ecological limits to the species geographic range. We additionally documented that spatial variation in relationships with land cover and anthropogenic factors were best explained by niche conservatism at the subspecies level, whereas climatic relationships were better explained by local adaptation. Main Conclusions: Based on these results, we propose that the current distribution of American black bear is determined by an evolutionary legacy of habitat relationships unique to each subspecies combined with more fine‐scale local adaptation to climatic conditions. This result suggests that black bears should be adaptable to climatic changes over the 21st century and that management of habitat and human‐bear relationships could be considered at the subspecies level. [ABSTRACT FROM AUTHOR]

Black bear (Ursus americanus) populations in California have increased in abundance and distribution despite rising trends in the urban encroachment of wildlands. As human-black bear conflicts increase, opportunities to study the relocation of black bears in an adaptive management setting are important for improving the management of this high-profile species. Habituated black bears, some tamed and made tractable through human-controlled food conditioning, were relocated to a remote region of the Klamath Mountains to analyze home range use, survival, return rates, and mortality. Relocated black bears with known outcomes demonstrated an 80% return rate, with 55% not surviving beyond five months. Female bears established home ranges significantly larger than males, and may suggest an enhanced maternal instinct in search of similar nutritional conditions prior to relocation. This study showed that the relocation of food-conditioned black bears resulted in high return rates, poor survival, and risk to public safety.

In Great Smoky Mountains National Park (GRSM or Park), American black bears (Ursus americanus) sometimes exhibit conflict behavior that requires resource managers to act. Management options for conflict bears are limited, and it is necessary to evaluate their effectiveness. We analyzed 26 years (1990–2015) of bear capture data and calculated and compared the success rates of the 2 main techniques used to manage bears exhibiting conflict behavior in GRSM: capture and relocation, and capture and on-site release. Overall success rates, defined as a captured bear that was not recaptured for later conflict behavior, for all conflict bears captured was 74%. Bears that were relocated after their first capture were more successful (87%) than those that were released on-site following their first capture (61%), and median time before recapture was greater for relocated bears (293 days) than those released on-site (65 days). [ABSTRACT FROM AUTHOR]