I studied the social organization and foraging ecology of eastern coyotes (<i>Canis latrans</i>) in Nova Scotia, from 1992 to 1997. Breeding pairs formed the nucleus of coyote social groups and generally traveled with 1-3 other coyotes during winter. Mean winter traveling group size was similar for packs utilizing white-tailed deer (<i>Odocoileus virginianus</i>) or snowshoe hare (<i>Lepus americanus</i>) as a primary food item. Thus, increased use of large prey was insufficient to explain group formation and cohesion of coyotes. Home-range sizes decreased significantly with deer and hare densities. Coyotes used the same territories during winter and summer, and from year to year. During winter, coyotes used, and killed deer, in areas of low deer density proportionately more than expected, likely owing to the increased vulnerability of deer in these areas. Territoriality prevented coyotes from concentrating in deer wintering areas. Based on the analysis of 2,443 scats, deer and hare were the dominant food items. During winter, coyotes killed 76-86% of the deer they consumed. Most deer killed by coyotes were not malnourished. Deer killing rates were negatively correlated with hare density. Mean urinary urea nitrogen: creatinine ratios were correlated positively with hare density. Overall, high use of deer appeared to have been associated with increased vulnerability due to winter severity or, in the case of young fawns, inability to escape. During mild winters, coyotes are forced to focus their hunting efforts on prey other than deer, regardless of density, due to low vulnerability of deer. When severe winter conditions occur, coyotes switch to feeding mainly on deer. Coyotes exhibited a Type I numerical response to the total biomass of deer and hares. Survival of fawns during summer was positively correlated with hare density. However, the total response of coyotes to changes in deer and hare density indicated that the presence of hare increased predation on deer by supporting higher coyote densities. A model based on the total response of coyotes to changes in deer and hare abundance predicted that food competition rather than predation probably regulated deer populations. Extirpation due to intense predation was a possible outcome for deer at densities <0.6 deer/km2.

Thèses (M.Env.)--Université de Sherbrooke (Canada), 2000. / Titre de l'écran-titre (visionné le 20 juillet 2006). Publié aussi en version papier.

This study investigated the acquisition of food by hand-reared coyotes, Canis latrans, of different social rank in a familiar area with and without novel objects (safe and potentially unsafe conditions). The first objective was to test the hypothesis that dominant animals are more hesitant than subordinates in approaching food in the presence of a novel stimulus. The results were that dominant pups usually were the first to feed in the absence of novel stimulus, and subordinate pups were the first to feed when novel objects were present.

Increasing global urbanization has altered landscapes for many wildlife species, including carnivores. Some carnivore species have been able to adapt to and even thrive in urban environments, including coyotes (Canis latrans). As coyotes continue to settle in more urban areas, human-coyote conflicts, such as attacks on humans or pets, are also increasing. Understanding the various factors affecting space use of urban coyotes may assist wildlife officials in reducing such conflicts. We conducted three studies of urban coyotes at varying spatial scales. First, using a captive population of coyotes at a fine spatial scale, we tested whether coyotes preferred urban, natural, or a mixture of habitat structures and whether sex, behavioral profile, biological season, or food manipulation affected coyote patch choice. When investigating novel environments, coyotes, especially females and bold animals, preferred a mixture of urban and natural structures rather than uniform structure. Food had no effect on patch choice, and coyotes appeared to be primarily motivated by the structure of the habitat rather than by the amount of food within each habitat. Second, we examined home-range size, habitat use, and resource selection of 22 coyotes at a local, population scale in the Denver metropolitan area. Mean (± SD) home-range size of resident coyotes (11.6 ± 11.0 km2) was smaller than ranges of transient coyotes (200.7 ± 232.4 km2). Home-range size did not vary by season or sex, but resident coyotes during the day had smaller home ranges than during the night. Coyotes had high percentages of developed lands (44.5 ± 18.9%) within their home ranges, but the percentage of coyote locations in natural lands (48.9 ± 22.4%) was higher than in developed lands (20.6 ± 11.7%). Coyotes selected for natural lands over developed lands, and they increased activity at night. Finally, we surveyed 105 urban areas in the United States, focusing on the occurrence of coyotes and conflicts on a national scale. Larger urban areas were more likely to contain both coyotes and conflicts, and were also more likely to have greater numbers of conflicts. Urban areas in the western regions with larger amounts of high-intensity development and less forested and agricultural areas were more likely to have conflicts. Most urban areas considered the management of conflicts to be of low priority. We conclude from these three studies that coyotes residing in urban areas prefer to spend their time in natural lands where human activity is minimized, especially forested and riparian areas that provide cover for coyotes and their native prey. Habitat management practices, such as sustainable urban planning and landscape design incorporating wildlife habitat requirements, may be an important tool in reducing human-coyote conflicts in highly urbanized environments.

The purpose of this study was to explore the response v of coyotes (Canis latrans) to certain olfactory and visual stimuli. It was assumed that the findings would be of value in refining techniques used in sampling and controlling coyotes. The specific objectives were to determine (1) if coyotes were more likely to approach and remain in the vicinity of a familiar than unfamiliar scent, (2) if the response to olfactory and visual stimuli differed, (3) if positively reinforcing an approach to the stimuli differentially altered the response to visual and olfactory stimuli, and (4) if the response differed with sex and social rank. The results failed to reject each of the null hypotheses implicit in the four objectives. Two factors that may have contributed to these findings were that subjects were too accustomed to "novelty" and there was a lack of behavioral control during the tests. On the basis of the results of this study, it is suggested that coyotes are so sensitive to their surroundings and so accommodating in their behavior that behavioral test results may simply reflect their responses to specific captive and test conditions.

Many canids live within hierarchical social systems that could promote differences in learning or in behavior between ranked individuals. Differences in foraging and territorial behavior have been observed between ranked coyotes (Canis latrans), yet effects of learning and social status on coyote behavior are not thoroughly understood. I explored a) coyote response to an artificial scent boundary and whether response differed by status, b) how foraging coyotes tracked temporal resource change, and c) how coyotes find spatially distributed food, and the effect of dominance on foraging behavior. I used male/female pairs of captive coyotes at the National Wildlife Research Center Predator Research Facility in Utah. Prior to testing, I identified social rank within pairs by testing for food dominance. In study 1, I laid a scent boundary and monitored space use with GPS and observed behavioral responses directly. All coyotes investigated and crossed the boundary, but were repelled more by human presence. Subordinates investigated and marked the boundary more than dominants. Further investigation is needed to mimic natural boundaries for management purposes. In study 2, I gave eight individual coyotes an operant test with concurrent variable interval (VI) schedules. I varied the ratio of resources and measured the time spent on two choices, then fitted the generalized matching equation to the data. I found that all coyotes efficiently tracked changes in resource ratios and matched their relative rate of foraging time to relative rate of resources. Matching theory provides an effective methodology to explore foraging strategies and behavioral flexibility in coyotes. In study 3, I tested 16 coyotes in a spatial foraging task. Coyotes searched for food in eight potential locations, and were tested individually and in respective pairs. I recorded the area and number of locations searched, approach time, and frequency of marking by dominant and subordinate coyotes. Results showed individual subordinates increased efficiency by relocating, but their efficiency decreased when foraging in pairs. Dominant coyotes did not increase efficiency in company by following subordinates. Coyotes marked the correct feeder more than incorrect feeders. Results suggest coyotes use memory and odor (scent marks) to find food, but that social status overrules information use.

Quantifying physiological stress may aid in a better understanding of how animals survive various environmental conditions. One noninvasive technique for assessing physiological stress in animals is to extract steroid hormones from fecal samples. This technique has the potential to aid in wildlife conservation by providing a better understanding of behavior and welfare for a variety of species. The objectives of the study were to (1) determine responses in plasma and fecal steroid hormone concentrations for coyotes (Canis latrans), (2) determine which steroid hormone (cortisol or corticosterone) was better for examining physiological stress responses for coyotes, and (3) determine the amount of time steroid hormone metabolites can be found in coyote scats during 2 different seasons. We first conducted an adrenocorticotropic hormone (ACTH) challenge in 16 coyotes and examined both plasma and fecal steroid hormone concentrations. An ACTH challenge is when there is an externally derived hormone (ACTH) injected into a subjects blood stream, which causes an increase in the subject’s circulating steroid hormones associated with physiological stress. We injected 16 treatment animals with ACTH and 16 control animals with a saline solution. We collected blood and fecal samples pre- and post-injection to measure steroid hormone concentrations. Radioimmunoassay, a laboratory method used to measure substances, was used to measure concentrations of steroid hormones in coyote blood and feces. To evaluate if steroid hormone concentrations remained in feces for an extended period of time we collected samples from 6 captive coyotes and left the samples in natural environmental conditions for 13 days. Each day a sub-sample was collected, and hormones were extracted and run through radioimmunoassay. We found increased steroid hormone concentrations after an ACTH challenge in both blood and feces, validating the use of fecal steroid hormone concentrations as a tool to measure physiological stress in coyotes. We also found there were no differences in levels of steroid hormone concentrations over 13 days. Our study provides validation for use of fecal steroid hormone concentrations in coyotes to quantify stress levels and confirms that steroid hormone metabolites are viable up to 13 days post deposition in coyote scat. This noninvasive tool can aid in the evaluation of the abilities of coyotes to adapt and exist in a variety of habitats.

The study was conducted to examine the effect of exploitation on population parameters of coyotes (Canis latrans). Hypotheses tested were: (1) Substantial levels of exploitation do not change spring and fall coyote densities significantly; (2) Coyote recruitment (reproduction and immigration) rates are unaffected by substantial levels of exploitation; (3) Annual coyote survival rates are not related to intensity of harvest rates; (4) Coyote emigration rates remain unchanged by substantial levels of exploitation. Coyote demographic parameters were measured from 1975 to 1978 for a treatment population subject to substantial exploitation (Curlew Valley, Utah and Idaho), and for an unexploited to lightly exploited control population (Idaho National Engineering Laboratory, INEL). Treatment and control populations were about 100 km apart on environmentally similar areas. Availability and utilization of prey also were similar for the two populations, with the major difference being in the type of lagomorph consumed. Relative spring densities, estimated by scent station indices, increased for both populations over the study period. Relative fall densities in the two areas were estimated by scent station lines, scat indices, and catch-effort indices and increased from 1975 to 1976, but were relatively constant thereafter. Estimates of absolute fall density from isotope labeling of feces also were similar within each area for 1977 and 1978. Neither spring nor fall density estimates were significantly different between areas in any given year or overall. Recruitment rates, as estimated from spring to fall increase in scent station visitation rates generally decreased over the study period, while estimates from age and sex structure of coyotes trapped in the fall increased for both populations over the study period. Estimated recruitment to fall populations (Pf) was consistently greater in Curlew Valley each of the four years, and overall was significantly greater than recruitment at the INEL. Spring to fall change in scent station indices was greater for Curlew Valley for all years except 1975. Annual survival rates were estimated for adults and juveniles marked with transmitters and/or ear tags using methods of statistical inference from band recovery data. Estimated survival rates for adults and juveniles were constant over the study period for each population and did not differ significantly between populations. Estimates of adult and juvenile survival and/or recovery (mortality) rates were significantly different within the Curlew Valley and INEL populations. Estimated hunting mortality rates for adults and juveniles remaining in the treatment population were 56 and 350 percent higher than similar estimates for the control population. Significantly higher in situ juvenile hunting mortality rates were associated with significantly lower nonhunting mortality and emigration rates. Emigration was not only greater from the control population, but it was distributed more evenly over the fall and winter. The following conclusions resulted from the study. Exploitation (kill) rates were substantially higher in the treatment population as expected. Observed differences in fall-winter adult and juvenile in situ kill rates did not produce significant differences in spring or fall densities, or in annual survival rates. Recruitment rates were related directly to hunting mortality rates, while emigration rates were related inversely.

Valles Caldera National Preserve (VCNP) managers were concerned about low elk recruitment observed at the same time as an apparent increase in sightings of coyotes and observations of coyote predation on elk calves. The goal of this study was to describe coyotes’ ecological interactions with elk, particularly coyote diet and movements on the Valle Grande, a large grassland meadow in the southeastern portion of the VCNP. We examined coyote diet by quantifying undigested remains of food items in coyote scats (feces). The most frequent taxa were rodents (montane voles and pocket gophers), elk (adult and calf), insects (grasshoppers and beetles), mountain cottontail rabbits, and plants. Most food types varied significantly seasonally and annually, likely due to climatic variation and the relative availability or vulnerability of food items. In particular, an increase in calf elk consumed during summer 2006 followed a dry winter when elk may have been in a lower nutritional state. We analyzed locations of 33 coyotes, obtained via global positioning system (GPS) collars and radio-tracking. We classified 23 coyotes as residents, living with a social group in a defined area (11.0 km2 mean), and 10 coyotes as transient, with less fidelity to specific areas and often travelling around the edges of the areas occupied by the four resident packs. Coyotes spent most of their time in dry meadow habitat. Coyotes spent more time in riparian habitat than expected based on its availability within home range and less time in forests. We found no relationship between coyote social cohesion (proximity of pack members to each other) and the proportion of elk in coyote diets. We concluded that coyote sociality on VCNP was relatively stable year-round despite changes in biological needs and prey size.

Vigilance behavior can aid in the detection of predators and may also play a role in observation of conspecifics, in food acquisition, and in the prevention of kleptoparasitism. However, in most occasions, vigilance is most important as an antipredator function. Generally, factors that increase the risk of predation also increase the amount of vigilance. We examined whether the reintroduction of the large predator, the wolf, in Yellowstone National Park (YNP) would influence coyote vigilance and foraging ecology. From December 1997 to July 2000, we collected 1743 h of coyote activity budgets. Coyote home ranges occurred within wolf territories (termed high-use or nonbuffer zone areas) and also between them in buffer zones. In high wolf use areas as well as when wolves were present, coyotes fed on carcasses much more; however, they increased the amount of vigilance and decreased rest to prevent predation. Wolf kills may provide a quick source of food and be energetically advantageous to coyotes; however, costs include increased vigilance, decreased rest, and a higher predation risk. Vigilance and avoidance behavioral responses to the reintroduction of large predators may ultimately be more common outcomes than actual killing by competing carnivores of prey. Keystone carnivore reintroductions have a variety of cascading effects throughout the ecosystem and can be driven by both numeric responses (trophic cascades) and behavioral responses ("behavioral cascades"). Behavioral cascades resulting from increased vigilance or spatial changes may lead ultimately to numeric changes and trophic cascades.