HABITAT SELECTION BY MOOSE IN AN EMERGENT LOW-DENSITY EDGE POPULATION

The Adirondack Park in northern New York contains about 700 moose (Alces alces) that persist as a low-density population (0.03 moose/km2) that occurs along the periphery of the moose’s southern range in the eastern United States. As part of a comprehensive effort to evaluate the status of the New York moose population, we fitted 26 moose with GPS collars during 2015–2017 and assessed summer (June–August) and winter (December–March) resource selection to understand moose space use and potentially limiting factors (e.g., climate, forage availability). Home ranges (x̄ = 22 km2) predominately contained deciduous forest, including managed forest stands recently harvested for timber. During summer moose did not exhibit variation in selection among years suggesting that adequate forage may be available across the landscape regardless of habitat type. Moose resource selection within home ranges was most variable during winter, and moose selected areas of managed timber during the most severe winters. Observed habitat selection highlights the potential of direct and indirect interactions with white-tailed deer (Odocoileus virginianus), given that deer in the Adirondack Park forage in areas selected by moose such as those with regenerative timber. Because white-tailed deer are an intermediate host for two fatal moose parasites (Parelaphostrongylus tenuis and Fascioloides magna), increase in habitat overlap between moose and deer could be detrimental to the long-term health of the New York moose population. Additionally, the dependence of both moose and white-tailed deer on regenerating forest stands for optimal forage could put commercial stands at risk of regenerative failure

ESTIMATING MOOSE ABUNDANCE BY USING STATISTICAL POPULATION RECONSTRUCTION TO FILL TEMPORAL GAPS IN AERIAL SURVEY DATA

Changes in moose populations are often evaluated using aerial surveys, which are expensive and dependent upon weather conditions and logistical constraints that sometimes preclude their completion each year. Statistical population reconstruction (SPR) provides a versatile framework for combining existing information from aerial surveys with auxiliary data such as telemetry-derived survival estimates to fill the temporal gaps in these surveys. We examined the performance of SPR in estimating moose abundance and other demographic characteristics in Minnesota during a year when the survey was not flown (2021; due to the COVID-19 pandemic) by combining data from 5 separate telemetry studies with aerial survey results from 2005–2020 and 2022–2024. We estimated an overall abundance of 3,212 moose (95% CI = 2,130–3,883) in 2021, with a corresponding bull-to-cow ratio of 0.84 (95% CI = 0.46–1.33) and a calf-to-cow ratio of 0.38 (95% CI = 0.22–0.70), which are consistent with previous survey results and independent population models. We used Leave-One-Out Cross-Validation (LOOCV) to confirm the accuracy and precision of these estimates, and to explore how additional years of missing aerial survey data would have impacted reconstructed estimates of demographic parameters. This validation analysis demonstrated that missing a single year of aerial survey data did not substantially impact model performance, and that additional years of missing data would have resulted in small but steady decreases in both the accuracy and precision of model-derived estimates. Our research also highlights the need for telemetry studies of yearling moose survival to improve the performance of SPR and provide a clearer picture of moose demography in Minnesota

SPATIAL AND TEMPORAL OCCURRENCES OF PRAIRIE MOOSE ACROSS AN URBAN TO RURAL GRADIENT IN SASKATOON, CANADA

The geographic range and abundance of North American moose (Alces alces) has varied over recent decades, with contractions in areas, recolonization of historical habitats and dispersals into new areas and, notably, increased moose sightings near developed, urban areas. The City of Saskatoon, Saskatchewan is located in semi-arid, open prairies and surrounded by high-intensity agriculture. Despite being atypical moose habitat, Saskatoon has experienced an increased frequency of moose observations at the urban-rural interface over the last several decades. We characterized spatial and temporal patterns in moose detections over the course of three study years (September 2020–September 2023) using data from 29 trail cameras distributed along an urban to rural gradient within the city boundary of Saskatoon. We quantified moose detections (n = 60) from photos (n = 249) collected at 12 of the camera trap sites. We detected moose each year of the study (8, 23, and 29 detections in years 1, 2, and 3, respectively). Moose detections were highest overall in July (n = 15) and at rural sites adjacent to the city (n = 47). Using generalized linear modeling, we found that moose were negatively associated with urban sites containing higher proportions of development (>50% impervious surface cover), and that detections occurred most frequently at night when darkness provided hiding cover and human activity was lowest. We provide suggestions and recommendations for future urban moose research and management

WOLF PREDATION ON MOOSE IN NORTH–CENTRAL BRITISH COLUMBIA

Moose populations declined substantially following widespread salvage logging of mountain pine beetle affected forests in interior British Columbia (B.C.) in the 2000s. The impact of wolf predation on moose was not well-understood in the context of extensive landscape change. We monitored 33 wolves across 11 packs in 2 interior B.C. study areas: Prince George South (PGS), characterized by extensive salvage logging features, and John Prince Research Forest (JPRF), also affected by salvage logging but less intensively. Because predation risk is a function of wolf density, space use, and predation patterns, we required a better understanding of these factors to develop management recommendations that could minimize predation risk to moose. Based on mid-winter pack counts and home range size, wolf density was about 10 wolves/1,000 km2 in PGS and 5 wolves/1,000 km2 in JPRF. We identified 290 kills made by wolves, predominantly moose in PGS (87%) and JPRF (75%). Wolves in JPRF preyed on more elk and deer than did wolves in PGS, and at 10% of the kill sites we investigated in JPRF, wolves had killed black bears. We found moose calves at 27% of the moose kill sites, compared with mid-winter estimates of standing proportions of calves in the population of 13–20%. After accounting for probability of the collared wolf attending pack kills, we calculated that wolf packs in PGS killed a moose every 4-8 days in winter and every 8–11 days in summer. In JPRF, wolf packs killed a moose every 7–12 days in winter and every 19–26 days in summer. However, when we considered the number of wolves per pack in the 2 study areas, the kill rates per wolf were similar. Based on recent midwinter moose density estimates, these kill rates would equate to 7–20% of the moose population for PGS and 2–8% of the moose population for JPRF. These predation rates may not be indicative of predation rates during the moose decline in the 2000s, so it is important to consider the mechanisms that could contribute to changing kill rates, including differential use by wolves and moose of highly modified landscapes and landscapes exposed to recent change such as widespread logging or wildfire. Based on our 2 study areas, extensive salvage logging creates habitat features that may support higher wolf densities and larger pack sizes, particularly in landscapes where moose are the dominant ungulate species

TWIG PRODUCTION PATTERNS AMONG MOOSE FORAGE SPECIES AND IMPLICATIONS FOR FOREST MANAGEMENT

A declining moose (Alces alces) population in northeastern Minnesota is a serious concern of the Gichi Onigaming Anishinaabeg (Grand Portage Band of Lake Superior Chippewa). A better understanding of the variation in moose forage production at the plant level among tree and shrub species and over time may be important to moose recovery in areas where nutrition may be limiting, while managers need practical methods to monitor forage density. Using data from an extensive 2019 moose browse survey at Gichi Onigaming (Grand Portage Indian Reservation, MN) and Minong (Isle Royale, MI), we fit models of twig production (number of twigs per plant) within moose reach as a function of species, canopy cover, and stem height. We validated the best fit model against an independent data set and used the model to simulate stand-level forage density over time for 3 tree species preferred by moose. Twig production varied non-linearly with stem height. An increasing then decreasing unimodal curve with height fit better than allometric models or species means. Peak twig production, height at peak production, and rate of production decline with height varied among species. Paper birch (Betula papyrifera) and balsam fir (Abies balsamea) generally had the greatest peak twig production, greatest heights at peak production, and lowest rates of decline with height. Among trees, quaking aspen (Populus tremuloides) generally had lower peak twig production, lower height at peak production, and greater rates of decline with height than most other trees and some tall shrubs. Peak twig production was greater under open canopy than under closed canopy for seven species. Model validation indicated that predictions were well correlated with observations and outperformed alternative models but had consistent over-prediction bias. Simulations of regenerating aspen, paper birch, and red maple (Acer rubrum) forests indicated that whereas aspen produced ~1.4-2.2 times more peak forage biomass than paper birch or red maple, paper birch and red maple produced usable forage densities for ~ 2-17 years longer than aspen. Finally, we provide a procedure to use the regression equations to estimate moose forage density from common forest regeneration survey data. Although the equations are suitable for monitoring, they should be used cautiously in high accuracy applications. Our findings suggest that diverse mixes of deciduous trees and shrubs resulting from post-harvest treatments likely provide abundant moose forage for longer durations than do nearly pure aspen stands often resulting from clearcutting alone in northeastern Minnesota

USING DISTANCE SAMPLING TO ESTIMATE MOOSE ABUNDANCE IN ISLE ROYALE NATIONAL PARK

Efficiently and accurately estimating moose (Alces alces) abundance in geographically isolated ecosystems like Isle Royale National Park (IRNP), Michigan, USA, is important for planning management actions. To estimate the population size of moose in IRNP, we flew a Robinson R44 helicopter to apply distance sampling in February 2022. We surveyed the entirety of IRNP with 149 transects that were 500-m wide and 0.16–13.36 km long depending on island width. We observed 439 moose in 253 groups, and fitted eight competing distance sampling models using two distance key functions (half-normal and hazard-rate), each with four covariate models: a null model, a univariate model for canopy size, a univariate model for group size, and a model with both canopy and group size. We used a Horvitz-Thompson-like estimator with the best model to calculate moose abundance on IRNP with 90 and 95% confidence intervals. The top model included a hazard-rate key function and the group size covariate. The estimated moose population was 1039 (90% CI 835–1293, 95% CI 800–1349). To test how sampling effort affected our estimates of moose abundance, we systematically removed 1/3 or 2/3 of transects from the dataset and repeated the analyses. The estimated abundance was similar (each 95% CI contained all 3 point estimates) when using all, 2/3, or 1/3 of transects, with the most precise estimate derived from the full dataset. Our population estimate was within the historical range of moose population estimates in IRNP and similar to a concurrent Gasaway-type estimate. While our survey covered the entirety of IRNP, we found that reducing effort by 1/3 provided a similar abundance estimate and precision. We concluded that distance sampling is a reasonable and efficient method to estimate moose density in IRNP. Monitoring how moose abundance varies in response to predator restoration efforts and climate change will help inform long-term management and planning in IRNP

RELATING AMBIENT AND BODY TEMPERATURE IN FREE-RANGING MOOSE: IMPLICATIONS TO HEAT STRESS AND SURVIVAL IN MINNESOTA

Climate change, or more explicitly heat stress, has been implicated as a driver of the rapid decline to Minnesota’s moose (Alces alces) population over the past 20 years. While often inferred that moose become heat stressed when ambient temperature exceeds thermal thresholds derived from captive moose, few studies provide physiological data to support that wild moose experience heat stress. Our study goals were to measure and explore relationships between ambient temperature and body temperature (Tb) of moose and evaluate their potential influence on heat stress and survival. We obtained continuous measurements of internal Tb of wild moose (n = 41; 23 females, 18 males) from 2013–2017 with mortality implant transmitters (MIT). We examined how frequently moose experienced ambient temperatures above reported upper critical temperatures (thresholds) in winter and summer that cause increased metabolism and panting. Moose often experienced days when ambient temperature was above all thresholds during summer (49.3–92.5% of summer days) and winter (36.3–78.5% of winter days). The percentage of days when a moose exhibited above normal Tb (≥ 39.17 °C) varied significantly between seasons, with conditions most likely to exceed the thresholds during summer (44–51% of summer days) but not winter. We found maximum daily Tb increased significantly with increasing maximum daily ambient temperature in summer. Predictions from our models suggest that moose in summer may experience elevated Tb, potentially indicative of heat stress, at maximum daily temperatures > 25 °C. We found Tb was most often higher in the evenings and overnight, as 76% of hot Tb occurred between 18:00–6:00 hr. The duration a moose maintained an elevated internal Tb was highly variable (mean = 32 min, range = 5 to 1,065 min). We also found that moose survival was related to the number of hot moose events (HME) they experienced on an annual basis. Moose that died (n = 14) had 2.0–2.8 x higher average HME per day than survivors over the course of a year. Our findings highlight the need for physiological data to support behavioral observations related to how endotherms respond to ambient temperature changes. Presumably, moose adopt behavioral tradeoffs in summer to mitigate heat stress that may reduce overall fitness and survival

WINTER HABITAT SELECTION OF MOOSE IN MAINE AND RUMINATIONS ON THE IMPACT OF CHANGING WEATHER CONDITIONS

Winter habitat use by moose (Alces alces) in response to climate change may reflect shifts in biotic and abiotic stressors that pose both environmental challenges and opportunities. Snow depth, temperature, winter length, and forest composition influence moose mobility, habitat use, and access to forage and cover resources. We analyzed habitat selection in winter home ranges of adult female moose (n = 96) over the course of six winters (2014–2019) to explore the influence of winter weather and forest composition on landscape and habitat use. Second order (home range) resource selection functions were estimated using generalized linear mixed models. Moose selected most strongly for forest habitat, specifically evergreen and mixed forests, which had similar strength of selection and represented ~50% of home ranges. The models identified a slight positive association with regenerating forest, although high levels of variance indicated a weak relationship. Contrary to our prediction, we did not detect any influence of weather conditions on winter habitat selection. Maine’s mosaic of forest types and commercial forestry seemingly provide adequate food and cover resources for moose regardless of winter conditions, with the three habitat types selected for representing ~70% of home ranges. Due to the coarse resolution of the data we analyzed, more specific data on forest structure such as stand age, canopy, and forage species may be required to identify finer relationships in habitat use and specific resource requirements during winter. It is possible that other factors associated with climate change, such as increases in deer (Odocoileus virginianus) populations, parasites, and disease will have greater influence on moose than habitat per se. However, because these potential influences are indirectly related to habitat use by moose, further research is warranted to best understand the multiple factors and relationships affecting winter habitat use

HABITAT USE AND SELECTION BY ADULT FEMALE MOOSE IN NORTHWESTERN MONTANA: VEGETATION TYPES, FOREST DISTURBANCE, AND THERMAL REFUGE

We studied summer and winter habitat use and selection of 34 GPS radio-collared adult female moose (Alces alces) living in largely managed coniferous forests in the Cabinet and Salish Mountains in northwestern Montana during 2013-2022. We built resource-selection function (RSF) models at the 2nd and 3rd order scales, and supplemented them by examining functional response to resource availability. We also assessed whether habitat selection was influenced by ambient temperature and used independently obtained field data to gain insight about the abundance of 2 important dietary shrubs, Salix spp. and Ceanothus velutinus. Moose selected strongly for intermediate elevations, denser canopy cover, and riparian habitats, but against non-vegetated and pine-dominated stands. As expected given their preference for deciduous shrubs, moose selectively used cut stands after the initial decade post-timber harvest. We observed a subtle preference for uneven-aged versus even-aged treated stands. Although uncommon, burned areas were used by moose, particularly ~15-35 years post-burn when conditions were conducive for Salix spp. and C. velutinus. Moose made subtle adjustments in habitat selection based on time-of-day and the prevailing temperature, exhibiting behavior consistent with the hypothesis that they seek cooler microclimates to aid thermoregulation. To benefit moose, habitat management in these and similar systems should diversify forest structure by setting back succession through timber harvest and allowing fires where possible, while providing mature proximate coniferous canopy for thermal relief

GROWTH AND VITAL SIGNS OF HAND-RAISED MOOSE CALVES IN ALASKA

Moose (Alces alces) have been raised in captivity for research and educational purposes for decades. Past research has focused mostly on milk replacer diets to produce healthy calves, with limited research of vital signs associated with routine health checks of young animals. We hand-raised 20 calves in 4 cohorts (2009, 2012, 2019, 2021) using commercially available milk replacers mixed with water only, and measured vital signs of 11 calves in 2019 and 2021. Growth rate from birth through weaning was 0.98 ± 0.02 kg • d-1, with maximum growth rate of ~1.3 kg • d-1 sustained for 6 weeks after weaning was initiated. Heart rate declined with age from 103.5 ± 2.6 beats • min-1 at 5 days old to 81.6 beats at 80 days old, whereas respiration rate increased from 16.3 ± 2.5 to 36.7 ± 4.4 breaths • min-1. Respiration rate increased with ambient air temperature from 11.1 ± 2.9 breaths • min-1 at 9 °C to 45.2 ± 3.2 at 26 °C. Respiration rate was highly variable after 3-week old calves began daily walks in a larger enclosure and ambient air temperature increased towards the summer maxima (July). Mean rectal temperature was 38.5 ± 0.03°C, and declined marginally with increasing vapor pressure and wind speed. Our hand-raising protocol and milk replacer diets produced calf growth rates higher than those reported previously, and similar to dam-raised calves consuming pelleted ration and available grass forage