No description available.

I studied free-living Richardson's ground squirrels (Spermophilus richardsonii) using telemetry and total body electrical conductivity (TOBEC) to evaluate overwinter energy utilization and the impact of seed caching on body composition of males. I excavated 51 hibernation systems and found that 66% of 35 males cached 1 to 4 species of seed in the hivernaculum. Pre-emergent euthermy was shorter for 3 non-caching (0.7 = 0.2 days) than for 13 caching males (4.0 = 2.8 days), and metabolic predictions of overwinter mass loss approximated actual loss for non-caching males, but over-estimated mass loss for caching males. I concluded that caching males recouped some of the mass lost during hibernation by eating the cache during the longer period of pre-emergence euthermy. Based on TOBEC, the recouped mass included both fat and lean tissue. I suggest that caching in one year is a cost of reproduction that offsets the energetic demands of mating the following year. / xii, 139 leaves : ill. ; 28 cm.

Although female Richardson’s ground squirrels (Urocitellus richardsonii) spend 80% of their lives sleeping and hibernating underground, studies on interactions and space-use have historically focused on the 20% of the time they spend aboveground. The type and frequency of aboveground interactions and degree of home-range overlap among female Richardson’s ground squirrels depend on their reproductive status and degree of kinship. The purpose of my study was to determine whether reproductive status and kinship influence underground sharing of space as well. I radio-collared 54 adult female Richardson’s ground squirrels (18 in 2008, 30 in 2009, and 6 in both years) of known maternal kinship in 5 spatially adjacent matrilines at a field site near Picture Butte, Alberta, Canada. Radio-collared females were located underground every evening after they retired and every morning before they emerged during both the 2008 and 2009 active seasons to determine sleep-site use and sleep-site sharing. The locations at which females were observed to retire in the evening (170 evenings) and emerge in the morning (141 mornings) in 2008 and 2009 were used to determine underground connections between surface entrances and underground sleep sites. Females commonly shared burrow systems, sleep sites, surface entrances, and underground connections after emergence from hibernation until mid-pregnancy and they shared again, though less frequently, after litters had been weaned, but they never shared underground features during lactation and hibernation. Close kin shared underground space more frequently than distant kin, and distant kin more frequently than non-kin. Variation in underground sharing of space over the active season and selective sharing with respect to kinship suggest that reproductive status and degree of kinship influence underground sharing. / xii, 121 leaves ; 29 cm

No description available.

The thesis is divided into four parts; 1.The implantation of the blastodermic vesicle, 2.The method of amnion formation in Citillus, 3.The anatomy and foetal membranes of a 25 mm. embryo, 4.The brain of a 9 mm. foetus.

Pilfering is thought to play a role in the evolution of scatter-hoarding strategies; but is not well understood in larder-hoarding animals. I studied intraspecific pilfering in red squirrels in Kluane, YT, Canada. The purpose of this project was to estimate the natural rate of cache pilferage, and to examine variation in pilfering behaviour. Results from experimental removal of territory owners, suggested that younger squirrels with smaller food caches were more likely to pilfer when given the opportunity. Survival over-winter was dependent on the number of cones cached and pilfering squirrels were less likely to survive. Using a mark-recapture study of marked cones I found that few individuals (14%) did any pilfering and stolen cones represented only 0.3% of total cones cached. It is clear that pilfering occurs at a much lower rate in Kluane than reported for red squirrels in other regions, and is less than rates reported for scatter-hoarding species. / Ecology

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 76-82). Also available via the Internet.

Presented as Thesis (Ph. D.)--University of Wisconsin--Madison, 1934. / Reprinted from American journal of anatomy, vol. 54, no. 3 (15 May 1934). Includes bibliographical references (p. 506).

Thesis (Ph. D. in Psychology)--Vanderbilt University, Dec. 2009. / Title from title screen. Includes bibliographical references.

Although scale is consistently identified as the central problem in ecology, empirical examinations of its importance in ecological research are rare and fundamental concepts remain either largely misunderstood or incorrectly applied. Due to the mobile and wide-ranging nature of wildlife populations, species-habitat modeling is a field in which much proliferation of multi-scale studies has occurred, and thus provides a good arena within which to test both scale theory and its application. Insufficient examination of a relevant breadth of the scale continuum could be an important constraint in all multi-scale investigations, limiting our understanding of scalar concepts overall. Here I examine several concepts of ecological scale by studying free-ranging populations of northern flying squirrels (Glaucomys sabrinus), purported to be a keystone species in northern forests. Coarse-grain digital forest coverage revealed that flying squirrels in the boreal and foothills of Alberta were not conifer specialists, rather forest generalists regarding stand type and age. Lack of coarse-grain scale effects led me to examine fine-grain data, including an assessment of scale domains using a novel continuum approach. Fine-grain data revealed important scale-related biases of trapping versus telemetry, namely that, at fine-grain scales, different habitat associations could be generated from the same data set based on methods alone. Then, focusing on spatial extent, I develop a true multi-scalar approach examining scale domains. First, I quantify only forest attributes across multiple extents, and demonstrate unpredictable scale effects on independent variables often used in species-habitat models. Second, including both independent (habitat) and dependent (squirrel telemetry) variables in the same approach, I demonstrate that the relative ranking and strength-of-evidence among different species-habitat models change based on scale, and this effect is different between genders and among life-history stage (i.e., males, females, and dispersing juveniles). I term this the “continuum approach”, the results of which question the validity of many published species-habitat models. Lastly, I attempt to clarify why existing models should be scrutinized by reviewing common rationales used in scale choice (almost always arbitrary), outlining differences between “observational scale” and the commonly cited “orders of resource selection”, and making a clear distinction between multi-scale versus multi-design ecological studies. / Graduate