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Allometric analyses of sexually selected structures have revealed many patterns of evolutionary and behavioural significance, for example, in weapons, ornaments, and genitalia. We investigated allometry of the baculum (penis bone) relative to body size in post-growth adults of three large mustelids: wolverine (Gulo gulo (Linnaeus, 1758)), northern river otter (Lontra canadensis (Linnaeus, 1758)), and sea otter (Enhydra lutris (Linnaeus, 1758)). The baculum grew over a longer period than did body size. Correlations among bacular variables were positive in post-growth adults. No regression slopes expressed positive allometry (i.e., slope > 1 for linear variables). These trends point to the possibility that bacular size is adapted to the average size of the reproductive tract of sexually mature female northern river otters and possibly sea otters, and that pre-ejaculatory ("pre-copulatory") selection is highest in those species. Bacular size varied more than skull or limb-bone size, and bacular shape also varied greatly. Species differed in size and complexity of the urethral groove and bacular apex, suggesting functional differences in intromission. Substantial variation in bacular shape resulted from healed fractures, especially in sea otter. Knowledge of copulatory behaviour, age of breeding, female reproductive anatomy, and genitalic interactions during intromission is needed for comprehensive understanding of bacular anatomy, allometry, and variation for these species. [ABSTRACT FROM AUTHOR]

Hoary marmots (Marmota caligata) dig burrows in alpine meadows rich in forage as ready refuge from potential predators. Refuge burrows enable hoary marmots to engage in risk-sensitive foraging when they are away from more secure resting burrows on talus slopes. Grizzly bears (Ursus arctos) commonly excavate refuge burrows while hunting marmots, substantially changing the physical characteristics of the burrow by removing earthen material. However, it is not known if marmots continue to use excavated burrows as refuge. We opportunistically inspected 22 burrows excavated by grizzly bears for use by marmots at two sites in northwestern Canada. We found marmot feces at 10 of 22 excavated burrows, indicating that marmots continued to use these burrows after they were excavated by bears. While marmots may dig several refuge burrows in alpine meadows, and bears may substantially modify them while hunting marmots, our observations indicate that some excavated burrows retain value for foraging marmots. However, the extent of their utility is unknown. We postulate several reasons why hoary marmots may use excavated burrows and suggest avenues for further research. [ABSTRACT FROM AUTHOR]

The epidermis of wild mammals is occasionally lacerated or punctured and wound care behaviours evolved to keep animals healthy in nature. Communal wound licking may promote healing of affected sites, relieve stress after a traumatic experience, and reinforce social bonds among individuals. Yet, there are few reported cases of communal wound licking in free‐ranging mammals. We report observations of communal wound licking in a social ungulate—free‐ranging bison (Bison bison). Two adult female bison presented with minor open puncture wounds after we chemically immobilized each of them with a dart fired from a rifle. The day after being darted, we observed three different adult bison lick the wounds of the two wounded bison. Both bison were <3 m of each other during this time and all of the observed wound licking occurred in <10 min. Our observation provides an additional example of communal wound licking in free‐ranging mammals and extends it to a social ungulate. Benefits to bison of communal wound licking are perhaps largely social. However, targeted research is needed to better understand both the frequency and cost and benefits of communal wound licking. [ABSTRACT FROM AUTHOR]

Variation in coat colour within mammal species is of enduring interest, likely because of its potential to be either adaptive or maladaptive. Coat colour in the genus Lynx tends to be stable, with little variation within species compared to that of other felids. Canada lynx (Lynx canadensis) have coats that typically are silver grayish in winter and reddish brown in summer with dark spots, and black hairs on the tips of their tails and ears. A rare pallid colourmorph is occasionally observed, suggestive of partial albinism. Here, I report the first record of a melanistic Canada lynx. The individual was photographed during summer in the Yukon (Canada). It had a black coat containing whitish gray guard hairs throughout, as well as whitish gray hairs in the facial ruff and the rostrum and dorsal regions. There are only a small number of records of coat colour polymorphisms in the genus Lynx. The adaptive significance of melanism in lynx is unknown, but the loss of camouflage when hunting during winter is likely maladaptive. [ABSTRACT FROM AUTHOR]

Few studies have explicitly examined habitat use by shrews (Sorex spp.) in the boreal forest of western North America. We conducted pitfall trapping in six common xeric habitat types in Yukon, Canada, to determine their relative use by shrews. The overall capture rate was 0.47 shrews per 100 trap nights (TN), with a total sampling effort of 3652 TN. Cinereus shrews (Sorex cinereus; 0.25 per 100 TN) were the most common species, followed by dusky shrews (Sorex monticolus; 0.14 per 100 TN) and American pygmy shrews (Sorex hoyi; 0.08 per 100 TN). Shrew capture rates and species richness was low in all habitat types sampled. Cinereus shrews were captured in similar numbers in boreal mixedwood forest and alpine shrub habitats, and rarely in other lowland forest habitat types. Dusky shrews were captured largely in alpine shrub habitats, while pygmy shrews were captured only in lowland forest habitat types. The relative use of alpine shrub habitat by cinereus shrews and dusky shrews was not expected. Our data was limited by low captures; however, we provide a first approximation of the relative use of common forest types and subalpine shrub habitat in the boreal forest of northwestern Canada. [ABSTRACT FROM AUTHOR]

Motion‐sensitive cameras are commonly used to monitor wildlife occupancy rates; however, few studies have assessed whether data from cameras are correlated with density estimates obtained from more traditional labor‐intensive methods such as those based on capture‐mark‐recapture. We used data from a boreal forest community to test whether camera data were correlated with densities estimated from independent monitoring methods. We placed 72 covert cameras in the forest around Lhù'ààn Mân' (Kluane Lake), Yukon, Canada, for 7 years and tracked changes in population densities by camera hit rates. We independently estimated population densities of snowshoe hares (Lepus americanus) and red squirrels (Tamiasciurus hudsonicus) using capture‐mark‐recapture via live trapping, and Canada lynx (Lynx canadensis), coyotes (Canis latrans), and moose (Alces americanus) by snow track transects. Density estimates obtained from conventional aerial surveys were also periodically available for moose. Except for red squirrels, camera hit rates were highly correlated with population density estimates obtained by traditional methods, including across a large range of estimated densities corresponding to cyclic population dynamics in several species. Accordingly, we infer that motion‐sensitive cameras could supplement or replace traditional methods for monitoring key species in boreal forest food webs. Using cameras to monitor population change has several advantages; they require less effort in the field, are non‐invasive compared to live‐trapping, include multiple species at the same time, and rely less on weather than either aerial surveys or snow track transects. Tracking changes across the vast boreal forest is becoming increasingly necessary because of climate and landscape change and our data validate the use of motion‐sensitive cameras to provide a useful quantitative method for state‐of‐the‐environment reporting. [ABSTRACT FROM AUTHOR]

Crucial to the success of studies based on capture-mark-recapture (CMR) designs is the retention (permanency) and recognition (readability) of marks to identify individuals. Several marking methods for small mammals (< 60 g) are available, but their efficacy and use is not well known. We implemented a targeted survey of experts to gather their experiences and opinions regarding marking small mammals. Respondents (n = 114) stated their beliefs, perceptions, and current and future use, of marking methods, as well as factors influencing their choices, based on Likert and rank order scale questions. We compared responses based on where researchers' studies occurred, their level of experience, and their subfield of mammalogy. Most respondents (73%) had > 5 years experience marking small mammals, with 60% each marking > 1,000 individuals. Respondents believed that ear-tagging was most preferable in terms of efficiency, impact to affected animals (survival, pain), and personal ethics, whereas passive integrated transponder (PIT)-tagging was the most preferable with regard to retention and recognition, and toe-clipping with respect to cost. Most respondents plan to use ear-tagging (78%) or PIT-tagging (70%) in the future. PIT- and genetic-tagging are expected to increase, and toe-clipping to decline, in the future. The factors influencing which marking method respondents used were ranked—in order of decreasing preference—as impact, retention, recognition, cost, efficiency, and ethics. There were few differences in the mean response or consensus among respondents, regardless of their experience, location, or subfield. Most respondents (66%) agreed that additional studies on the performance and impact of various marking methods are needed to assess their costs and benefits for CMR-based studies. Ultimately, choice of marking method will depend on the species, research question, available resources, and local legislation and permitting. Our study, however, illustrates that collective insights by experienced mammalogists may aid individual researchers in deciding on study designs and protocols, particularly early career scientists. [ABSTRACT FROM AUTHOR]

Capture and handling of wildlife is often an important component of studies where detailed demographic, behavioral, physiological, or health data are required. Yet, capturing and handling wildlife is sometimes controversial and lacking public support because of concern about effects on individuals. Investigating potential effects of capturing wildlife is also important to inform data‐censoring protocols when using information obtained from captured animals. We investigated the short‐term effect of helicopter‐based capture and handling on movements of free‐ranging bison (Bison bison) that were chemically immobilized in Yukon, Canada. We examined daily movement rates, home range size, and displacement of global positioning system‐collared individuals immediately after capture and for 20 days thereafter. Our results indicate that there is a minimal short‐term effect of helicopter‐based capture on bison movements. Significant differences from apparent pre‐capture movement behavior were observed only within 24 hours after capture. We observed variation among individuals, however, with some animals taking up to 10 days to return to apparent pre‐capture movement rates, whereas others had no measurable response to capture. Despite individual variation, >80% of individuals had returned to apparent pre‐capture movement behavior within the first 5 days after capture. Furthermore, sex‐based effects were evident: females increased their daily movement rates, home range size, and displacement after capture, whereas males had either no effect or decreased movement rates. Our results suggest that movement rates are altered for only a short period after capture and, therefore, should not have severe negative effects on bison using our protocols. Accordingly, researchers should censor the first 10 days after capture from their analyses to avoid using biased information. Our study should also help inform public discourse regarding capturing and handling wildlife for research or management purposes. © 2019 The Wildlife Society Helicopter‐based capture of global positioning system (GPS)‐collared bison resulted in significant differences from pre‐capture movement behavior only within 24 hours after capture. We observed sex‐based differences in response to being captured and variation among individuals, with some animals taking up to 10 days to return to apparent pre‐capture movement rates. Accordingly, the first 10 days after capture should be censured from analyses to avoid using biased information. [ABSTRACT FROM AUTHOR]

Recently, a new generation of global positioning system (GPS) collars has become available that provides limited daily location fixes, a relatively long battery life, and are low-cost, compared to full-featured GPS collars. However, their performance is untested, and assessing these biases is needed to inform study designs and data analysis protocols. We used stationary tests of 15 Lotek LifeCycle GPS collars – an example of low-feature GPS collars – to measure the accuracy of location fixes. In addition, we deployed Lotek Lifecycle GPS collars on 153 caribou Rangifer tarandus and 24 bison Bison bison in Yukon and Alaska, to assess their field performance. We examined differences among species, sex, location fix schedule, and latitude, on four performance metrics (FSR, 3D-V FSR, DOP and DSR). Stationary trials indicated that mean precision (4.3 ± 4.0 m [SD]) and accuracy (6.0 ± 4.7 m) of location fixes was excellent, and FSR was good (87.2%), albeit both were slightly affected by forest canopy cover. Field performance varied by species and sex. Notably, the mean DSR for male bison was dismal (27.4 ± 24.2%) likely because of their behaviour, and the mean FSR, 3DV-FSR and DOP, for male caribou was poor (FSR = 57.3 ± 2.0%), compared to collars deployed on female caribou (72.2 ± 1.7%) or female bison (77.9 ± 1.4%). We also observed that the VHF transmitters often failed when the collar malfunctioned. Biases in the accuracy and performance of these low-cost GPS collars should be taken into account when designing studies. Researcher's contemplating investing in low-feature GPS collars require information on their 'real-world' performance so that they can decide whether they are appropriate for their intended application. Moreover, researchers need to consider biases in their GPS collar data prior to embarking on field studies and when conducting analyses with the data collected from them. [ABSTRACT FROM AUTHOR]

Recently, a new generation of global positioning system (GPS) collars has become available that provides limited daily location fixes, a relatively long battery life, and are low‐cost, compared to full‐featured GPS collars. However, their performance is untested, and assessing these biases is needed to inform study designs and data analysis protocols. We used stationary tests of 15 Lotek LifeCycle GPS collars – an example of low‐feature GPS collars – to measure the accuracy of location fixes. In addition, we deployed Lotek Lifecycle GPS collars on 153 caribou Rangifer tarandus and 24 bison Bison bison in Yukon and Alaska, to assess their field performance. We examined differences among species, sex, location fix schedule, and latitude, on four performance metrics (FSR, 3D‐V FSR, DOP and DSR). Stationary trials indicated that mean precision (4.3 ± 4.0 m [SD]) and accuracy (6.0 ± 4.7 m) of location fixes was excellent, and FSR was good (87.2%), albeit both were slightly affected by forest canopy cover. Field performance varied by species and sex. Notably, the mean DSR for male bison was dismal (27.4 ± 24.2%) likely because of their behaviour, and the mean FSR, 3DV‐FSR and DOP, for male caribou was poor (FSR = 57.3 ± 2.0%), compared to collars deployed on female caribou (72.2 ± 1.7%) or female bison (77.9 ± 1.4%). We also observed that the VHF transmitters often failed when the collar malfunctioned. Biases in the accuracy and performance of these low‐cost GPS collars should be taken into account when designing studies. Researchers contemplating investing in low‐feature GPS collars require information on their 'real‐world' performance so that they can decide whether they are appropriate for their intended application. Moreover, researchers need to consider biases in their GPS collar data prior to embarking on field studies and when conducting analyses with the data collected from them. [ABSTRACT FROM AUTHOR]

Fecal pellet counts are often used to assess trends in ungulate population size and habitat use. However, various factors may influence the physical decay and disappearance of pellets, where disappearance may be a result of physical decay and other factors (e.g. trampling, scattering and concealment by vegetation). Knowing pellet decay and disappearance rates in different habitats is a prerequisite to acquiring reliable information from pellet counts. We examined elk Cervus canadensis pellet decay and disappearance of individual pellets and pellet groups in six habitats in the boreal forest of northwestern Canada. We monitored 120 pellet groups deposited in May 2008 at 4, 12, 16 and 28 month intervals (i.e. the end of each of three plant growing seasons) to assess differences in physical decay and disappearance. Pellet decay and disappearance varied among habitats. In moist habitats, pellets showed little sign of decay by the end of our study, likely due to a short plant growing season. In drier, open habitat types, pellet decay was more rapid, likely due to exposure to sun and wind. By the end of our study, the percent of pellets remaining varied from a 14-82% among the sampled habitats. Pellets in moist forest habitats had the lowest decay rates but the highest disappearance rates, whereas those in dry, grassland sites had the highest decay, but the lowest disappearance rates. Our study further demonstrates that ungulate pellet decay and disappearance may differ substantially among habitats, which has important implications for the design of ungulate monitoring programs that utilize pellet counts. We conclude by recommending that fecal accumulation rate (FAR) methods are likely more appropriate in our study area than fecal standing crop (FSC) methods for estimating elk density, because FAR methods are less prone to biases associated with differential pellet decay and disappearance among habitats. [ABSTRACT FROM AUTHOR]

Renal calculi (kidney stones) are often reported in domestic animals and occasionally wildlife; however, prevalence is rarely reported for free-ranging wildlife. Our aim was to determine the prevalence of renal calculi in a large sample of free-ranging wolverine ( Gulo gulo ) from a harvested population in Yukon, Canada. We tested for an effect of sex, age, and body condition, on the presence of renal calculi. Macroscopic examination revealed renal calculi in 48 of 537 (8.9%) wolverine. Bilateralism was low, with only 6 of 48 (12.5%) affected wolverine having calculi in both kidneys. Calculi were found in similar prevalence between the sexes. A significantly higher percentage of adults (≥2 years old) had renal calculi than sub-adults (<2 years old). When considering adults alone, prevalence was 12.7% for males and 17.8% for females. The mean age of affected females was not statistically different than the sample population, but the mean age of affected adult males was 2 years older than unaffected adult males. Mean body condition scores for wolverine with and without calculi were not statistically different for females or males. Mineral composition was determined for calculi from 29 wolverine. Calculi from most wolverine (90%) were composed of 95–100% ammonium acid urate, with magnesium ammonium phosphate (struvite) and calcium phosphate (apatite) as minor (≤5%) constituents. Our study is one of the first to document the prevalence of renal calculi in a free-ranging population of wildlife. Prevalence of renal calculi in adult wolverine from northwestern Canada was substantial; however, the pathogenesis and clinical significance of nephrolithiasis in wolverine is unknown. [ABSTRACT FROM AUTHOR]

ABSTRACT The potential for interspecific competition for food resources is a key consideration when newly introduced ungulates occupy a shared range with resident native species. Management plans in Yukon, Canada, for reintroduced bison ( Bison bison) and introduced elk ( Cervus canadensis) called for an assessment of competition for food resources between these species and resident populations of caribou ( Rangifer tarandus), thinhorn sheep ( Ovis dalli), and moose ( Alces americanus). To assess potential competition among ungulates, we examined dietary overlap of 7 ungulate species in southwestern Yukon, Canada. We compared diet composition at the forage class level and composite diet indices (diversity, evenness, and niche breadth) among species found at 2 elevation classes (high [≥1,200 m ASL] and low [<1,200 m ASL]) during summer and winter, using data derived from microhistological analyses of feces. Composite indices and percent of key forage classes in diets differed among ungulates during summer and winter and at both high and low elevations. Potential dietary overlap for most species pairs was low to moderate (0.07-0.60). However, for bison and thinhorn sheep at high elevations, and bison and semi-feral horses ( Equus ferus caballus) at low elevations, it was high (0.82-0.97) during both summer and winter, indicating potential for food competition. Dietary overlap between species appeared to be based primarily on morphophysiological classification (i.e., browser-intermediate-grazer), rather than body size. Bison, horses, and sheep were all grazers. Intermediate species, such as introduced elk, had only moderate dietary overlap with several species. We concluded that the potential for competition for food resources based on dietary overlap between bison and sheep and bison and horses may be high in our study area, depending on forage availability, but for all other species pairs in our study area the potential for forage competition is low to moderate. © 2015 The Wildlife Society. [ABSTRACT FROM AUTHOR]

After being virtually ignored, bats in northwestern Canada and Alaska have recently been subject to increasing attention by scientists, resource managers, and the public. We review recent advances in bat research in the region and identify key priorities for future research, including what we believe is needed to provide a more coordinated approach to filling in these knowledge gaps. Our knowledge of the diversity and distribution of bats has improved considerably as a result of dedicated survey efforts. Scientists have provided a tantalizing glimpse into the natural history and ecology of bats in far northwestern North America and some of the unexpected adaptations they exhibit in response to the challenges imposed by northern environments. Despite these recent advances, further work is required to document the distribution of bats in the region; identify key summer roosting habitats and hibernacula; assess population status and trends; evaluate the impact of anthropogenic change and develop mitigation strategies; and better understand the natural history ecology of bats in the region. Improving our knowledge of these aspects of bat biology will be useful for informing conservation planning initiatives and environmental impact assessment processes. To ensure that new information is reliable and accessible, we strongly recommend that researchers strive to meet minimum evidentiary standards; deposit data, samples and voucher specimens in appropriate repositories; coordinate monitoring efforts and data collection; and publish or otherwise report results. We hope that our concluding remarks will help guide bat research in northwestern Canada and Alaska, and that the hard-earned results obtained in future studies will impart a positive impact on bat conservation in the region. [ABSTRACT FROM AUTHOR]

The bat fauna of Alaska and northwestern Canada remains poorly known, principally due to a lack of dedicated surveys. To better assess the diversity of bats in the region, we conducted full-spectrum acoustic surveys at several sites in Yukon, Canada. During our surveys we obtained the 1st acoustic records of Hoary Bat (Lasiurus cinereus) and Long-Legged Myotis (Myotis volans) in Yukon. Neither species had been documented previously in the territory, but one or both species were known from adjacent Alaska, British Columbia, and Northwest Territories. Characteristics of certain echolocation calls of Hoary Bats and Long-legged Myotis are difficult to confuse with other species that might also occur in the region. In addition, we made other noteworthy recordings; however, species identification for these other echolocation calls was ambiguous. These 1st records significantly increase our knowledge of the ranges of these bat species in Yukon, Canada. Further acoustic surveys, coupled with live captures, will help us further understand the diversity and distribution of bats in Yukon. [ABSTRACT FROM AUTHOR]

Diurnal roost sites are a critical resource for bats. Despite their importance, we know little about the roosting habits of Little Brown Myotis (Myotis lucifugus) in the boreal forest of northwestern Canada and Alaska. To locate diurnal roost sites and determine minimum distances to foraging areas, we radio-tagged 10 Little Brown Myotis (7 adult females, 3 adult males) in the boreal forest of southwestern Yukon, Canada. All of the females roosted in a single building, with 1 using a bat house for 2 nights. In contrast, the males used a variety of roost sites, including buildings, rock cliffs, and trees, and switched roosts periodically. We observed sex-biased movements, with adult males traveling a significantly shorter distance between their diurnal roost sites and a key foraging area than adult females. Males tended to roost near a key foraging area, whereas radio-tagged females flew >5 km from their diurnal roosts to forage. Our data are some of the first obtained via radio-telemetry for Little Brown Myotis in the boreal forest and confirm that the roosting behavior of the sexes is different. That all of the radio-tagged females primarily used 1 roost site in town and flew relatively far to a key foraging area suggests that these critical resources may be somewhat limiting in our study area. [ABSTRACT FROM AUTHOR]

bstract: Estimating abundance is a key component of wildlife management and capture–mark–recapture (CMR) methods are commonly used. Photography has been widely explored as a method of ‘marking’ individuals for CMR. However, it is most often used on species with unique markings, and application to species without obvious marks remains challenging. We tested a likelihood-based photogrammetric method to identify individuals from four species of ungulates: muskox (Ovibos moschatus; 31 photos of 16 individuals), thinhorn sheep (Ovis dalli; 110 photos of 32 individuals), mountain goats (Oreamnos americanus; 47 photos of 19 individuals) and mule deer (Odocoileus hemionus; 60 photos of 30 individuals). Misidentification rates (false rejection [FRR] and false acceptance [FAR] rates) varied widely between species (FRR =  < 1–13%, FAR = 2–22%), as did matching success rates (48–96%). Muskox and sheep had the highest matching success rates (96% and 88%, respectively), while those for goats (80%) and deer (58%) were lower. Automated matching success rate for deer and sheep, calculated based on the top-ranked photograph, was compared to a user-generated matching success rate. The latter was significantly higher in all cases, indicating that the final subjective step was important. Significant observer bias was found for deer, but not sheep. The main findings of our study were that a photogrammetric approach to individual recognition of ungulates was species specific and sensitive to the inclusion of horn measurements, season, photo quality, and final selection from top choices by the user. While matching success rates of photogrammetry was reasonably good (> 90%) for muskox, it was only moderately accurate 80–90% for sheep and goats, and poor (< 80%) for deer. Future work should address the temporal stability of horn measurements, seasonal effects, feasibility of capturing useable photographs from remote cameras, and application to other species. [ABSTRACT FROM AUTHOR]

Abstract: Most studies of small mammal responses to habitat alterations focus on dominant species, with a resulting lack of information for rare species. Jumping mice (Order Rodentia: Dipodidae) tend to be rare in small mammal trapping studies; thus, little is known of their response to habitat alterations, such as clear-cut logging. We examined the spatial distribution of meadow jumping mice (Zapus hudsonius) captured in 3 upland habitat types (forest interior, forest edge, and logged forest) in the boreal forest of southeastern Yukon, Canada. Meadow jumping mice were the third most common rodent captured, and consistently constituted 19.7% of captures in all of the habitat types. Meadow jumping mice may not be rare in some boreal mammal assemblages. Significantly less animals were captured in the forest interior compared to the forest edge or logged forest (P <0.05). A preference or avoidance of sharp habitat edges created by logging was not detected. Logged areas may be more preferred over unlogged areas by meadow jumping mice because they provide relatively diverse and abundant food resources and cover. To provide data more useful for biodiversity conservation, we suggest that studies of small mammals in forest ecosystems deploy a variety of trap types and sample at sufficient intensity to provide information on both dominant and rare species. [Copyright &y& Elsevier]

The article investigates the predatory behavior of gray wolf in scavenging of reintroduced scavenging American bison in southwestern Yukon. It cites several incidents of bison predation by wolves in 2007 and 2009 but no wolves were directly observed preying on bison because only the rumen remained in the scene. It cites that several sporadic, aerial, and occasional observations were conducted but none had been reported on scavenging of predation of bison. It states that predation of wolf on bison may have substantial implication for the population dynamics of both species and alternate species, and that scavenging are important ecological processes.

The article discusses the diurnal and nocturnal foraging behavior of little brown bat and great horned owl in Yukon. It states that the application for mist nests are highly recommended to capture bats on the Lubbock River, a meandering river to control the current of water and contains several oxbows. The author emphasized that the net held under water by the weight of the owl which identifies from the puncture wounds or by drowning. Moreover, a large hole in a certain net suggested that the owl may have taken at least one other bat from net while it was not monitored.

Fisher (Martes pennanti) occur broadly across northcentral North America, and are a species of conservation concern in most of western North America. Fisher reach the northwestern edge of their distributional range in the Yukon, Canada; however, their abundance and distribution has been poorly documented there. We used museum collections, trapping records, and sightings to update the relative abundance and distribution of Fisher in the Yukon between 1956 and 2009, with a particular emphasis on the last 3 decades. We compiled 100 records of Fisher that were trapped, observed, or whose tracks were noted in the Yukon. Harvest data suggested that Fisher may be increasing in relative abundance in the Yukon, but densities likely are very low. Anecdotal observations and harvest of Fisher in southwestern Yukon have increased in the last 10 to 20 y and suggest that they may be expanding their range westward. Trapping records and museum collections in adjacent Alaska and northwestern British Columbia corroborate records from the Yukon. Monitoring Fisher will be necessary to confirm changes in the abundance and distribution of Fisher in the Yukon and neighboring jurisdictions. [ABSTRACT FROM AUTHOR]

Alces americanus (Moose) are relatively new to Labrador, having only colonized the area in the late 1940s, and little is known about this population. We conducted large-scale aerial surveys for Moose in a 122,000-km² area during winter 2000 and in a 29,900-km² area in winter 2001. Moose densities were low in each area (1.6-3.0 Moose per 100 km²). Bull:cow ratios were nearly even and calf:cow ratios were relatively high, indicative of a population exposed to little hunting or predation pressure. Twinning rates were low, suggesting low range productivity. Moose used riparian areas and hardwood stands in higher proportion than their availability in winter (P < 0.05). Open habitats (conifer-lichen woodlands, bogs and fens, burned forest, and barren areas) were used in lower proportion than their availability. These data may provide the basis for developing habitat suitability maps for Moose in late winter across central Labrador. [ABSTRACT FROM AUTHOR]

Many mammals cross large rivers to access seasonal habitats, yet river crossing behavior is poorly acknowledged or understood. Crossing large rivers is inherently risky, with vessel traffic and flooding events increasing the risk of drowning. We investigated river crossing behavior by threatened bison (Bison bison) in the boreal forest, using data from 11 GPS-collared animals to identify when and where they cross a major river. We used kernel densities of GPS locations to identify crossing hotspots, and developed resource selection function (RSF) models that used habitat characteristics to explain crossing behavior based on a priori hypotheses. We then predicted high-probability crossing areas along a 400-km stretch of river using the best-supported RSF model. Bison regularly crossed the river (x̄ = 8.6 crossings/100 days), particularly during summer months. Model selection results suggested that bison may have chosen river crossing areas that maximized access to forage. Bison preferred to cross the river near islands and areas with high seismic line densities, both of which were likely preferred summer foraging habitats. In addition, islands may have been used as temporary stopovers while crossing the river, or for relief from biting insects. Bison crossed the river where the channel was relatively narrow (x̄ = 400 ± 213 m [SD]) and chose days when river discharge was low, likely to reduce the risk of drowning, exhaustion, or hypothermia. While based on a small sample of collared bison, predictions about high-probability crossing areas may be used to inform mitigation measures aimed at reducing bison drowning caused by vessel traffic, which is expected to increase as resource development expands in the region. Our approach may be informative for identifying river crossing hotspots for other mammals that cross major rivers. [ABSTRACT FROM AUTHOR]

Many mammals cross large rivers to access seasonal habitats, yet river crossing behavior is poorly acknowledged or understood. Crossing large rivers is inherently risky, with vessel traffic and flooding events increasing the risk of drowning. We investigated river crossing behavior by threatened bison (Bison bison) in the boreal forest, using data from 11 GPS-collared animals to identify when and where they cross a major river. We used kernel densities of GPS locations to identify crossing hotspots, and developed resource selection function (RSF) models that used habitat characteristics to explain crossing behavior based on a priori hypotheses. We then predicted high-probability crossing areas along a 400-km stretch of river using the best-supported RSF model. Bison regularly crossed the river (⁠ x ¯ = 8.6 crossings/100 days), particularly during summer months. Model selection results suggested that bison may have chosen river crossing areas that maximized access to forage. Bison preferred to cross the river near islands and areas with high seismic line densities, both of which were likely preferred summer foraging habitats. In addition, islands may have been used as temporary stopovers while crossing the river, or for relief from biting insects. Bison crossed the river where the channel was relatively narrow (⁠ x ¯ = 400 ± 213 m [ SD ]) and chose days when river discharge was low, likely to reduce the risk of drowning, exhaustion, or hypothermia. While based on a small sample of collared bison, predictions about high-probability crossing areas may be used to inform mitigation measures aimed at reducing bison drowning caused by vessel traffic, which is expected to increase as resource development expands in the region. Our approach may be informative for identifying river crossing hotspots for other mammals that cross major rivers. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the author discusses various reports within the issue on topics including the advances in bat research in northwestern Canada and Alaska, diversity and distribution of bats in the region and the ecology and life history of bats at northern latitudes.

Presents a study on habitat selection by forest bats in relation to mixed-wood stand types and structure in the forests of central Ontario. Quantification of structural characteristics in the stands sampled for bat activity; Habitat selection models; Response of bats to structural characteristics; Bat use of stand types; Bat species composition.

Surveillance of endoparasites at the host community level is rarely reported for ungulates. Yet, changes in the composition and abundance of species in ungulate assemblages, coupled with environmental and climate change, bring into focus the need for baseline data on endoparasite occurrence in host species at the community level. We investigated the prevalence and intensity of eggs of endoparasites in feces of a dynamic boreal ungulate community in Yukon, Canada, that included reintroduced bison (Bison bison), as well as introduced elk (Cervus canadensis), naturally colonizing mule deer (Odocoileus hemionus), and resident populations of caribou (Rangifer tarandus), moose (Alces americanus), and thinhorn sheep (Ovis dalli). We also examined the change in endoparasite prevalence and intensity in bison fecal samples collected eight years apart. The prevalence of eggs detected in feces differed across species for most endoparasite groups. We also provide new records of several endoparasites in novel hosts or new geographic records. We detected a substantially greater prevalence and intensity of trichostrongyle-type eggs in bison feces between samples collected eight years apart. Our data emphasize the need for targeted pathogen surveillance programs to monitor the movement of various ungulate and associated endoparasites. This is particularly pertinent since our data potentially supports evidence for the continued northward expansion and host switching of protostrongylid species, which may have health implications for animals at a new interface. [ABSTRACT FROM AUTHOR]

The article describes a study which focuses on the invasiveness and evidence of breeding by house mice in an urban area of Yukon. It suggests that the mice are native to northern India and have migrated to various parts of the world because of human activities. As suggested, the study included mice, which were collected from occupied buildings and outside near unoccupied buildings in Whitehorse and highlights that the mice population consists of two color variants. The article also confirms their existence in cold climates and locations at higher altitudes. It also suggests that the introduction of these mice in Yukon is through unintentional human transport including shipments of food and other goods.

The article focuses on the aberrations in coat color of the American Red squirrels, also known as Tamiasciurus hudsonicus. It informs that aberrations in coat color of Scuiridae are common. It informs that the coat color of the Red Squirrel appeared faded or washed out. The Red Squirrel is considered to be of Isabelline coloration. Isabelline is used for birds that have faded plumage. It informs that the Isabelline color variant of Red Squirrels appears to be quite rare. It further informs that in the late 1980s, near Burwash Landing of Yukon, only two Red Squirrels with Isabelline color were collected.

The article discusses the social impact of the reintroduction of American Bison (Bison bison) as part of a national recovery program in southwestern Yukon Canada. It lists its several ecological functions which is said to be of great significance in evaluating their restoration in the ecosystem. It notes the different observations that were documented on the used of bison's fur as nesting materials by birds and small mammals including the American Red Squirrels (Tamiasciurus hudsonicus). The latter's nests including the types of fur used are evaluated.

Mapping habitat selection by threatened species provides critical information for conservation planning. For reintroduced populations, understanding habitat selection is also necessary to predict dispersal and inform selection of new reintroduction sites. Efforts to restore bison Bison bison to the boreal forest hinge on the persistence of geographically isolated populations that occupy diverse landscapes, and for many populations selected habitats are unknown. We used location data from GPS-collared bison to develop seasonal resource selection function (RSF) models and predictive maps for the reintroduced 'Nahanni' population. We accounted for variation in individual behaviour by calculating averaged population-level selection coefficients from individual RSFs, and we compared these results to a pooled RSF from all bison. Individual RSFs revealed variation in habitat selection that was not always captured by the pooled RSF, although there were some consistencies. Bison strongly selected forage-rich graminoid-dominated wetlands (fens) during winter, but less so in summer when there were potential tradeoffs with poor footing and biting flies. In summer, bison selected alternative sources of forage such as herbaceous, shrubby and fluvial habitats (i.e. riverine islands and gravel bars). The observed association with fluvial habitat may be an adaptation to low forage availability on this landscape. Bison also selected roads and anthropogenic clearings associated with resource development, demonstrating potential for human–wildlife conflict. Our predictive maps highlight areas of conservation interest, and should be considered in land use planning and environmental assessments. We demonstrate the value of foraging habitat for forest-dwelling bison, particularly in winter. Identifying forage-rich habitat patches, and connectivity between them, is important when considering sites for new reintroductions or expansion of existing populations. More broadly, our approach may be used to identify areas of high conservation interest, where resources do not allow extensive sample sizes of GPS-collared animals. [ABSTRACT FROM AUTHOR]

Groundberries are an important component of the flora of the boreal forest and provide seasonally important food for many birds and mammals, as well as local people in northern Canada. Here, we ask whether there has been a change in the cover of groundberries in the Yukon boreal forest over the last two decades. We monitored five common species at undisturbed forest sites spaced 300 km apart. At our Kluane site, we monitored 710 fixed quadrats per year for 26 years (1997–2022), and at Mayo 500 quadrats per year for 18 years (2005–2022). The cover of four species, Arctostaphylos uva-ursi (L.) Spreng. (bearberry), Arctostaphylos rubra (Rehder & E.H. Wilson) Fernald (red bearberry), Empetrum nigrum L. (crowberry), and Geocaulon lividum (Richardson) Fernald (toadflax), declined annually by 0.2%–0.8% at both sites. In contrast, Vaccinium vitis-idaea L. (lingonberry) increased annually by 0.5% and 0.8%. We tested whether increases in summer temperature and rainfall were correlated with the observed changes but found no significant relationships. These boreal plants are changing in abundance, but we have limited data on the extent and speed of these changes. We recommend experiments to understand the cause(s) of these changes in groundberry productivity. Our study is a start in monitoring important berry species in this critical ecosystem of northern Canada. [ABSTRACT FROM AUTHOR]

The article presents a paper that discusses the predation of Arctic Ground Squirrels by Bald Eagles. Topics discussed include Arctic Ground Squirrels as a keystone species in northern environments and found in abundance in Yukon Wildlife Preserve, Canada, Bald Eagles predation of Arctic Ground Squirrels in the Aleutian Islands, Alaska, and predation of Ground Squirrels by Bald Eagles on Kavalga Island, Alaska.

The article reports on an observation of an unusual colored North American porcupine. A Porcupine on the shore of Teslin Lake In Yukon, Canada has been observed on August 5, 2014, that was of a sandy or cream color. There were few observable dark hairs, and the eyes and nose were of a normal pigmentation. The color aberrations such as isabelline and albinism are maladaptive in North American Porcupines, otherwise they would likely be more commonly observed in nature.

The assumption that activity and foraging are risky for prey underlies many predator–prey theories and has led to the use of predator–prey activity overlap as a proxy of predation risk. However, the simultaneous measures of prey and predator activity along with timing of predation required to test this assumption have not been available. Here, we used accelerometry data on snowshoe hares (Lepus americanus) and Canada lynx (Lynx canadensis) to determine activity patterns of prey and predators and match these to precise timing of predation. Surprisingly we found that lynx kills of hares were as likely to occur during the day when hares were inactive as at night when hares were active. We also found that activity rates of hares were not related to the chance of predation at daily and weekly scales, whereas lynx activity rates positively affected the diel pattern of lynx predation on hares and their weekly kill rates of hares. Our findings suggest that predator–prey diel activity overlap may not always be a good proxy of predation risk, and highlight a need for examining the link between predation and spatio-temporal behaviour of predator and prey to improve our understanding of how predator–prey behavioural interactions drive predation risk. [ABSTRACT FROM AUTHOR]

Limited information exists on mercury concentrations and environmental drivers of mercury bioaccumulation in high latitude terrestrial carnivores. Spatial patterns of mercury concentrations in wolverine (Gulo gulo, n = 419) were assessed across a 1,600,000 km2 study area in relation to landscape, climate, diet and biological factors in Arctic and boreal biomes of western Canada. Hydrogen stable isotope ratios were measured in wolverine hair from a subset of 80 animals to assess the spatial scale for characterizing environmental conditions of their habitat. Habitat characteristics were determined using GIS methods and raster datasets at two scales, the collection location point and a 150 km radius buffer, which was selected based on results of a correlation analysis between hydrogen stable isotopes in precipitation and wolverine hair. Total mercury concentrations in wolverine muscle ranged >2 orders of magnitude from 0.01 to 5.72 μg/g dry weight and varied geographically, with the highest concentrations in the Northwest Territories followed by Nunavut and Yukon. Regression models at both spatial scales indicated diet (based on nitrogen stable isotope ratios) was the strongest explanatory variable of mercury concentrations in wolverine, with smaller though statistically significant contributions from landscape variables (soil organic carbon, percent cover of wet area, percent cover of perennial snow-ice) and distance to the Arctic Ocean coast. The carbon and nitrogen stable isotope ratios of wolverine muscle suggested greater mercury bioaccumulation could be associated with feeding on marine biota in coastal habitats. Landscape variables identified in the modelling may reflect habitat conditions which support enhanced methylmercury transfer to terrestrial biota. Spatially-explicit estimates of wet atmospheric deposition were positively correlated with wolverine mercury concentrations but this variable was not selected in the final regression models. These landscape patterns provide a basis for further research on underlying processes enhancing methylmercury uptake in high latitude terrestrial food webs. [ABSTRACT FROM AUTHOR]

The article presents a study investigating on the first record of a brown rat or Rattus norvegicus from the Yukon . It was on July 9, 2010 that researchers have captured a female brown rat in an interior of an occupied house in Whitehorse, Yukon. The captured rat was identified as a brown rat than a black rat or Rattus rattus by its characteristics such as in the head, tails, and its small ears covered with fine hairs. Moreover, the origin of the specie was unknown but is was believed to have been transported by humans from either the Alaskan coast, the inland routes from central North America, or it may be an escaped pet.

Some mammal species inhabiting high-latitude biomes have evolved a seasonal moulting pattern that improves camouflage via white coats in winter and brown coats in summer. In many high-latitude and high-altitude areas, the duration and depth of snow cover has been substantially reduced in the last five decades. This reduction in depth and duration of snow cover may create a mismatch between coat colour and colour of the background environment, and potentially reduce the survival rate of species that depend on crypsis. We used long-term (1977–2020) field data and capture–mark–recapture models to test the hypothesis that whiteness of the coat influences winter apparent survival in a cyclic population of snowshoe hares (Lepus americanus) at Kluane, Yukon, Canada. Whiteness of the snowshoe hare coat in autumn declined during this study, and snowshoe hares with a greater proportion of whiteness in their coats in autumn survived better during winter. However, whiteness of the coat in spring did not affect subsequent summer survival. These results are consistent with the hypothesis that the timing of coat colour change in autumn can reduce overwinter survival. Because declines in cyclic snowshoe hare populations are strongly affected by low winter survival, the timing of coat colour change may adversely affect snowshoe hare population dynamics as climate change continues. [ABSTRACT FROM AUTHOR]

Climate warming is causing asynchronies between animal phenology and environments. Mismatched traits, such as coat color change mismatched with snow, can decrease survival. However, coat change does not serve a singular adaptive benefit of camouflage, and alternate coat change functions may confer advantages that supersede mismatch costs. We found that mismatch reduced, rather than increased, autumn mortality risk of snowshoe hares in Yukon by 86.5% when mismatch occurred. We suggest that the increased coat insulation and lower metabolic rates of winter‐acclimatized hares confer energetic advantages to white mismatched hares that reduce their mortality risk. We found that white mismatched hares forage 17–77 min less per day than matched brown hares between 0°C and −10°C, thus lowering their predation risk and increasing survival. We found no effect of mismatch on spring mortality risk, during which mismatch occurred at warmer temperatures, suggesting a potential temperature limit at which the costs of conspicuousness outweigh energetic benefits. [ABSTRACT FROM AUTHOR]

Abstract: Community and ecosystem changes are happening in the pristine boreal forest ecosystem of the Yukon for 2 reasons. First, climate change is affecting the abiotic environment (temperature, rainfall and growing season) and driving changes in plant productivity and predator–prey interactions. Second, simultaneously change is occurring because of mammal species reintroductions and rewilding. The key ecological question is the impact these faunal changes will have on trophic dynamics. Primary productivity in the boreal forest is increasing because of climatic warming, but plant species composition is unlikely to change significantly during the next 50–100 years. The 9–10‐year population cycle of snowshoe hares will persist but could be reduced in amplitude if winter weather increases predator hunting efficiency. Small rodents have increased in abundance because of increased vegetation growth. Arctic ground squirrels have disappeared from the forest because of increased predator hunting efficiency associated with shrub growth. Reintroductions have occurred for 2 reasons: human reintroductions of large ungulates and natural recolonization of mammals and birds extending their geographic ranges. The deliberate rewilding of wood bison (Bison bison) and elk (Cervus canadensis) has changed the trophic structure of this boreal ecosystem very little. The natural range expansion of mountain lions (Puma concolor), mule deer (Odocoileus hemionus) and American marten (Martes americana) should have few ecosystem effects. Understanding potential changes will require long‐term monitoring studies and experiments on a scale we rarely deem possible. Ecosystems affected by climate change, species reintroductions and human alteration of habitats cannot remain stable and changes will be critically dependent on food web interactions. [ABSTRACT FROM AUTHOR]

The article discusses the research on berries consumption behavior of bighorn sheep in the arid interior region of British Columbia, Canada. Topics discussed include the variability in diet of bighorn sheep, benefit of Elderberry consumption to the bighorn sheep of deserts and thanking of persons Matthias M Clyde, SK Aspen Clyde and D Forest Clyde as they have assisted the researchers with their field observations.

Aim We surveyed the genetic variability of deermice (genus Peromyscus) at the north-western edge of their range to test for occupancy in multiple, hypothesized ice-free regions during the late Pleistocene and explore post-glacial dynamics. Location North-western North America. Methods We used sequences from four independent nuclear and mitochondrial loci from 341 specimens of Peromyscus maniculatus, Peromyscus keeni and Peromyscus sp. (Yukon) to assess species limits, population structure, and demographical change as a result of historical climate change, using a Bayesian approach. Species distribution models were built in MaxEnt to explore the niche overlap amongst genetically distinct species. Results Divergence amongst three lineages began before the last interglacial, and each shows signs of post-glacial expansion. Multilocus species trees strongly support P. keeni and Peromyscus sp. (Yukon) as independent from P. maniculatus. Substantial substructure was observed for P. keeni across the fragmented Alexander Archipelago. Northern lineages or clades ( Peromyscus sp. and P. keeni) differed in potential ecological distributions. Main conclusions At the extreme north-western range of deermice in North America, three distinct lineages persist reflecting divergence in at least three ice-free regions [Beringia, Coastal (near Southeast Alaska) and Southern Continental] throughout the latest Pleistocene glacial cycles. Although spatially proximate in Yukon, no locations were identified where these lineages are in contact. Further, west along the Pacific Coast, P. keeni is widespread across the complex landscape of Southeast Alaska, yet there is limited contemporary gene flow amongst island populations, a finding consistent with the barriers produced by rising sea levels at the end of the Last Glacial Maximum. [ABSTRACT FROM AUTHOR]

The bat fauna of northwestern Canada remains poorly known, principally owing to a lack of dedicated surveys across this vast region. To better assess the diversity of bats in the region, we compiled records from several acoustic survey projects and capture sessions whose purpose was to inventory bats in Yukon and northwestern British Columbia (BC) from 2013 to 2018. During our surveys we obtained the 1st apparent acoustic records for Yuma Myotis (Myotis yumanensis), Californian Myotis (M. californicus), Long-eared Myotis (M. evotis), Silver-haired Bat (Lasionycteris noctivagans) and Eastern Red Bat (Lasiurus borealis) from this region. We also captured 2 Long-eared Myotis in northwestern BC. Additionally, our surveys provided range extensions of Northern Myotis (M. septentrionalis), Long-legged Myotis (M. volans), and Hoary Bat (Lasiurus cinereus). Finally, by deploying bat detectors in late autumn, and in some cases throughout the winter, we provide data about seasonal patterns for bat activity in some locations, revealing that bats in northwestern BC may be active as late as 29 October and emerge as early as 30 March, a pattern similar to that observed in southern BC. By combining data from several disparate surveys, conducted for different reasons by different researchers, we were able to provide a fuller picture of the bat fauna of this vast region. Our data provides further evidence that the bat fauna of northwestern Canada is richer than previously documented. [ABSTRACT FROM AUTHOR]

Estimating population densities of small mammals (< 100 g) has typically been carried out by intensive livetrapping, but this technique may be stressful to animals and the effort required is considerable. Here, we used camera traps to detect small mammal presence and assessed if this provided a feasible alternative to livetrapping for density estimation. During 2010-2012, we used camera trapping in conjunction with mark-recapture livetrapping to estimate the density of northern red-backed voles (Myodes rutilus) and deer mice (Peromyscus maniculatus) in the boreal forest of Yukon, Canada. Densities for these 2 species ranged from 0.29 to 9.21 animals/ha and 0 to 5.90 animals/ha, respectively, over the course of this investigation. We determined if hit window--the length of time used to group consecutive videos together as single detections or "hits"--has an effect on the correlation between hit rate and population density. The relationship between hit rate and density was sensitive to hit window duration for Myodes with R² values ranging from 0.45 to 0.59, with a 90-min hit window generating the highest value. This relationship was not sensitive to hit window duration for Peromyscus, with R² values for the tested hit windows ranging from 0.81 to 0.84. Our results indicate that camera trapping may be a robust method for estimating density of small rodents in the boreal forest when the appropriate hit window duration is selected and that camera traps may be a useful tool for the study of small mammals in boreal forest habitat. [ABSTRACT FROM AUTHOR]

Snowshoe hare cycles are one of the most prominent phenomena in ecology. Experimental studies point to predation as the dominant driving factor, but previous experiments combining food supplementation and predator removal produced unexplained multiplicative effects on density. We examined the potential interactive effects of food limitation and predation in causing hare cycles using an individual‐based food‐supplementation experiment over‐winter across three cycle phases that naturally varied in predation risk. Supplementation doubled over‐winter survival with the largest effects occurring in the late increase phase. Although the proximate cause of mortality was predation, supplemented hares significantly decreased foraging time and selected for conifer habitat, potentially reducing their predation risk. Supplemented hares also lost less body mass which resulted in the production of larger leverets. Our results establish a mechanistic link between how foraging time, mass loss and predation risk affect survival and reproduction, potentially driving demographic changes associated with hare cycles. [ABSTRACT FROM AUTHOR]

Little brown bats (Myotis lucifugus) are a widely distributed species in North America that have been decimated by the fungal disease white-nose syndrome. As such, little brown bats are the focus of monitoring and research initiatives that often include capturing and handling free-ranging individuals. We examined the stress response of 198 adult female little brown bats after being captured from three bat houses, during the summer. Our objective was to inform best practices to researchers capturing and handling bats in the wild. We compared the stress response among bats held for <3 min (baseline), 15–30 min, or >30 min, and then among bats held alone or in a group with conspecifics. We measured the levels of plasma total and free cortisol, maximum corticosteroid binding capacity (MCBC), and blood glucose. Relative to baseline, total and free cortisol levels were significantly higher in bats held for 15–30 min and higher still in those held for > 30 min. Blood glucose levels were elevated after >30 min of holding. MCBC levels showed no differences among holding times. We detected a weak effect of social holding condition, with solitary-held bats having lower total cortisol levels than group-held bats, but MCBC, free cortisol, and blood glucose levels showed no effect of social holding condition. Our findings demonstrate that capture time should be minimized and suggest that little brown bats should be handled and released within 30 min of capture as means of reducing stress. Further, solitary holding did not appear to increase stress measures, which supports holding bats individually after capture, instead of in groups, to reduce risk of pathogen and parasite transmission. [ABSTRACT FROM AUTHOR]

Forage availability, snow depths, and winter temperatures were assessed to determine if they might impose range constraints on introduced elk (Cervus elaphus) that voluntarily colonized a 95 km2 area of southwest Yukon (Canada) in 1959. Parkland-like vegetation of stunted aspen (Populus tremuloides) and nonforest upland plant communities, which is atypical vegetation for a boreal forest environment, composed 30% of the colonized area. About 95% of the area produced less than 300 kg/ha of forage, which represents poor productivity compared to more southern elk ranges. In the remaining 5%, indigenous graminoid communities produced (average ± SD) 408 ± 131 kg/ha of forage, exceeded only by nonindigenous roadside vegetation with 652 ± 115 kg/ha. Data from radio-collared animals indicated that most elk occurrences (38% year-round) were associated with parkland-like vegetation, and fecal pellet groups were six times as frequent in indigenous graminoid vegetation as in forest vegetation. Late February 2011 snow depths of 41 ± 7 cm, during a year with a below-normal snowfall, suggested a potential for reduced winter access to forage. Meteorological data from 1981 - 2010 indicate that one-third of winter daily minima in the study area were likely lower than -20°C, a threshold below which the metabolism of an elk calf must increase to maintain its body temperature. Each assessed habitat variable was unfavorable to elk compared with other western North American winter ranges, which may have limited the development of a more robust population in the southwestern Yukon. [ABSTRACT FROM AUTHOR]

Background: Species of Trichinella are globally important foodborne parasites infecting a number of domestic and wild vertebrates, including humans. Free-ranging carnivores can act as sentinel species for detection of Trichinella spp. Knowledge of the epidemiology of these parasites may help prevent Trichinella spp. infections in northern Canadian animals and people. Previous research on Trichinella spp. in wildlife from Yukon did not identify risk factors associated with infection, or the diversity and identity of species of Trichinella in regional circulation, based on geographically extensive sampling with large sample sizes. Methods: In a cross-sectional study, we determined the prevalence, infection intensity, risk factors, and species or genotypes of Trichinella in wolverine (Gulo gulo) in two regions of Yukon, Canada, from 2013–2017. A double separatory funnel digestion method followed by mutiplex PCR and PCR-RFLP were used to recover and identify species of Trichinella, respectively. Results: We found larvae of Trichinella in the tongues of 78% (95% CI 73–82) of 338 wolverine sampled. The odds of adult (≥ 2 years) and yearling (1 year) wolverine being Trichinella spp.-positive were four and two times higher, respectively, compared to juveniles (<1 year). The odds of Trichinella spp. presence were three times higher in wolverine from southeast than northwest Yukon. The mean intensity of infection was 22.6 ± 39 (SD, range 0.1–295) larvae per gram. Trichinella T6 was the predominant genotype (76%), followed by T. nativa (8%); mixed infections with Trichinella T6 and T. nativa (12%) were observed. In addition, T. spiralis was detected in one wolverine. Out of 22 isolates initially identified as T. nativa in multiplex PCR, 14 were analyzed by PCR-RFLP to distinguish them from T. chanchalensis, a recently discovered cryptic species, which cannot be distinguished from the T. nativa on multiplex PCR. Ten isolates were identified either as T. chanchalensis alone (n = 7), or mixed infection with T. chanchalensis and T. nativa (n = 2) or T. chanchalensis and Trichinella T6 (n = 1)]. Conclusions: Wolverine hosted high prevalence, high larval intensity, and multiple species of Trichinella, likely due to their scavenging habits, apex position in the food chain, and wide home range. Wolverine (especially adult males) should be considered as a sentinel species for surveys for Trichinella spp. across their distributional range. [ABSTRACT FROM AUTHOR]