John A. Crouse

• State of Alaska

Quantifying moose forage on the landscape is challenging but can provide managers with an indication of habitat quality. This moose foraging sampling technique builds off established vegetation sampling methods; however, we have adapted the methods to incorporate moose foraging ecology. We documented moose forage quality and quantity at 5 time peri...

Wildlife contend with seasonal fluctuations in resource availability and have adapted survival and reproductive strategies to overcome resource limitations. Many northern ungulates are adapted to a dynamic nutritional landscape and rely on somatic reserves accumulated during the short growing season. Moose (Alces alces) populations in the boreal fo...

Northern ungulates contend with Setaria yehi and Rumenfilaria andersoni, filarioid nematodes that are transmitted by ectoparasitic blood-feeding arthropods, which can result in animal and population level impacts. Setaria yehi microfilariae can be detected in fresh blood samples using a modified Knott's test, or by postmortem detection by genetic s...

Moose (Alces alces) in boreal habitats feed and rest where they are exposed to Dipteran flies and the parasites they carry. We collected 31,905 flies during the summer from 12 habituated moose on the Kenai Peninsula, Alaska. Moose flies, Haematobosca alcis (Snow), Diptera: Muscidae—a species that completes its entire life cycle on or around moose—a...

Moose (Alces alces) in the boreal forest habitats of Alaska are unlike other northern ungulates because they tolerate high densities of flies (Diptera) even though flies cause wounds and infections during the warm summer months. Moose move to find food and to find relief from overheating (hyperthermia) but do they avoid flies? We used GPS collars t...

Measurements of reproductive and stress-related hormones in keratinous tissues (e.g. hair, claws, hooves, baleen) can provide a record of stress and reproductive response in wildlife. We evaluated a method to collect keratin tissue from hooves of immobilized moose (Alces alces) and validated enzyme immunoassays for measuring cortisol and progestero...

Background Timing of reproductive events can be crucial for a species’ population growth and stability. Accurate detection of reproductive phenology presents a challenge to scientists studying wild species, including moose (Alces alces). Currently, there are several established methods for monitoring reproductive activity and events in domestic rum...

Background Monitoring the behavior of wild animals in situ can improve our understanding of how their behavior is related to their habitat and affected by disturbances and changes in their environment. Moose (Alces alces) are keystone species in their boreal habitats, where they are facing environmental changes and disturbances from human activitie...

Background Timing of reproductive events can be crucial for a species’ population growth and stability. Accurate detection of reproductive phenology presents a challenge to scientists studying wild species, including moose (Alces alces). Currently, there are several established methods for monitoring reproductive activity and events in domestic rum...

Long-standing reports of open sores on the hind legs of moose (Alces alces) have been recorded in Alaska (as well as Canada, Europe, and Michigan), eliciting concerns about causes and infection. We used histological and genomic methods to investigate the sores from 20 adult moose on the Kenai Peninsula, Alaska. We paired this with thermal imagery a...

Young animals are particularly vulnerable to environmental stressors that can impair growth and compromise survival. We used salivary cortisol, a glucocorticosteroid hormone, to measure possible stress response of moose calves in Alaska to the abundance of biting and non-biting flies relative to calf age, time of day, and ambient air temperature. W...

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 comm...

Vaginal implant transmitters (VITs) are a popular tool in ungulate parturition studies and have been used in moose ( Alces alces ), but their potential impact on animal performance has not been thoroughly assessed. We looked at potential short‐term impacts of VIT use on maternal condition through assessments of neonate calf mass, early calf surviva...

Body composition studies are critical for evaluating the accuracy of nutritional condition indices for predicting body components. We evaluated >40 indices of nutritional condition for caribou (Rangifer tarandus (Linnaeus, 1758)) using 29 female caribou captured from three populations in Alaska (USA) that ranged in condition from 2.3% to 11.2% inge...

Management of large herbivores depends on providing habitats for forage supply and refuge from risks of temperature, predation and disease. Moose (Alces alces) accumulate body energy and nutrient stores during summer, while reducing the impact of warm temperatures through physiological and behavioural thermoregulation. Building on the animal indica...

We assessed the thermal tolerance of moose by using the physiological indicator for daily amplitude in core body temperature (>1.25 °C) to identify days when moose entered their thermal "tolerance zone". Additionally, we evaluated a suite of moose physiological and endocrine responses to warm environmental conditions during the warm season. Heat re...

We tested the concept that moose (Alces alces) begin to show signs of thermal stress at ambient air temperatures as low as 14 °C. We determined the response of Alaskan female moose to environmental conditions from May through September by measuring core body temperature, heart rate, respiration rate, rate of heat loss from exhaled air, skin tempera...

Management and research of moose (Alces alces) in Alaska, USA, often require chemical immobilization; however, moose may be prone to capture‐induced hyperthermia while immobilized. We chemically immobilized moose with carfentanil citrate and xylazine hydrochloride to measure rump fat depth, collect blood and fecal samples, and to deploy modified va...

Food intake may limit the ability of browsing mammals to gain body mass during the growing season when the leaves and stems of woody plants are most abundant. Moose are highly productive browsers with high demands for energy and nutrients, particularly during lactation. Using an indigestible marker, we estimated dry matter intake of free ranging ad...

Variation in core body temperature of mammals is a result of endogenous regulation of heat from metabolism and the environment, which is affected by body size and life history. We studied moose (Alces alces) in Alaska to examine the effects of endogenous and exogenous factors on core body temperature at seasonal and daily time scales. We used a mod...

Mortality implant transmitters (MITs), a device that can record continuous rumen temperature, have been deployed in wild moose (Alces alces) in Minnesota, USA, to understand physiological and behavioral responses of moose to increasing ambient temperatures. We compared temperatures collected using MITs to temperatures collected using vaginal implan...

Measuring body temperature in free-ranging ungulates is challenging. We evaluated a vaginal implant transmitter (TVIT) modified to collect continuous body temperature of captive and wild female moose (Alces alces) in Alaska, USA. We deployed TVITs in 18 moose between 2014 and 2016. We manually removed the TVIT after 51–338 days of deployment and sa...

Recent uses for rumen boluses, such as mortality implant transmitters (MITs), in wildlife have made it necessary to adapt deployment techniques developed for livestock. In 29 and 30 attempts to place MITs in Minnesota free-ranging moose ( Alces alces) in 2013 and 2014, respectively, success was achieved 83% and 63% of the time. In 2014, new methods...

Moose rumen samples from Vermont, Alaska and Norway were investigated for methanogenic archaeal and protozoal density using real-time PCR, and diversity using high-throughput sequencing of the 16S and 18S rRNA genes. Vermont moose showed the highest protozoal and methanogen densities. Alaskan samples had the highest percentages of Methanobrevibacte...

The costs and benefits of alternative migratory strategies are often framed in the context of top-down and bottom-up effects on individual fitness. This occurs because migration is considered a costly behavioral strategy that presumably confers explicit benefits to migrants in the form of either decreased predation risk (predation risk avoidance hy...

Moose populations in southeastern Alaska have a relatively short history as a result of recent de-glaciation of regional landscapes. The colonization trajectories of such populations have typically been characterized by irruptive fluctuations. That is, following a period of initial establishment, populations generally have increased rapidly (possib...

Thesis (M.Sc.)--Lakehead University, 2003. Includes bibliographical references.