Thesis (M. Sc.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on July 12, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Ecology, Department of Biological Sciences, University of Alberta. Includes bibliographical references.

Thesis (M.S.)--Eastern Illinois University, 2008. / Includes bibliographical references (leaves 39-43).

Thesis (M.S.)--Michigan State University. Dept. of Zoology, 2008. / Title from PDF t.p. (viewed on July 27, 2009) Includes bibliographical references. Also issued in print.

Thesis (M. Sc.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on July 10, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Environmental Biology and Ecology, [Department of] Biological Sciences, University of Alberta." Includes bibliographical references.

Thesis--Wisconsin. / Includes bibliographical references (leaves 92-98).

This thesis evaluates how developmental conditions influence settlement, survival, and yearling primiparity in juvenile red squirrels. This was accomplished by comparing the fates of offspring from food supplemented versus non-supplemented mothers, and by using logistic regression to evaluate the effects of body mass, resource availability, and reproductive parameters on juvenile success. Maternal nutrition, previous and present year's cone production, and body mass contributed significantly to settlement and survival during all juvenile life history stages (emergence, settlement, and overwinter survival). Heavier than average juveniles were also more likely to reproduce as yearlings. Nevertheless, natal body mass was not a predictor of recruitment, indicating persistent influence of early developmental conditions on life history fates above and beyond mass effects. A greater impact of resource availability than body size on fitness among red squirrels may reflect this species' reliance on hoarded food rather than body fat for energy reserves.

No description available.

The reproductive condition of male and female red squirrels (Tarniasciurus hudsonicus) in southern British Columbia was studied in relation to age, season, relative population level, and foods utilized. The reproductive cycle of males and females is described on the basis of gross anatomy and histological characteristics. A low population on Vancouver Island was studied in 1966 and 1967 and a high population was studied near Princeton, B.C. in 1967. The habitats are similar in both regions. The low 1966 population had a late breeding season in which all females sampled produced two large litters. The ovulation rate for the two litter season averaged 5.12 per litter. The second ovulation occurred shortly after the birth of the first litter, before the uteri and vaginae came into full estrus condition. In 1967 both the low Vancouver Island population and the high Princeton population had early breeding seasons when nearly all adults bred yet only one third of the yearling females participated. Only single litters were produced in both areas. The ovulation rate was 4.11 per litter in the low Vancouver Island population and 3.58 per litter in the high Princeton population. Preimplantation losses of about 11% were fairly constant in both years. Postimplantation losses were not present in the low 1966 population, were about 19% in the high 1967 population, and were not determined in the low 1967 population. Similarities between the high and low 1967 populations and differences between the low 1966 and low 1967 populations on Vancouver Island suggest that density was not the primary force Influencing productivity. Another explanation is found in the evaluation of the primary food sources. Conifer cones are the main winter food of the red squirrel. Lodgepole pine cones were the main food source before the highly productive breeding season in I966 while Douglas fir cones made up the diet before the less successful breeding season in 1967. The fruiting habits of the conifers is discussed and It appears that it is advantageous for the squirrel to feed on lodgepole pine cones. A good winter food supply is particularly important to the red squirrel since it breeds during the late winter and it's already high metabolic rate increases still more during cold winter weather. It is inferred that the winter food supply may influence the relative capacity of the female to produce young. The timing of the breeding season is quite variable and seems to be affected by the severity of the winter weather. / Science, Faculty of / Zoology, Department of / Graduate

The effects of food abundance on the population dynamics and territorial behaviour of red squirrels were examined during a four year study in south-central British Columbia, Canada. I used a short-term, ad libitum addition of supplemental food in Douglas fir (low squirrel population density) and white spruce (high squirrel population density) forest habitats to examine changes in demography and spacing behaviour. Removal experiments in spring and autumn assessed the effect of residents on breeding density and juvenile recruitment and the influence of settlement patterns on recolonization density. If food is a limiting resource, I expected population density, recruitment, body weight, growth rates and reproduction to increase on the food supplemented areas. Population density in spruce control habitat was consistently twice as high as in Douglas fir control habitat (26 vs. 15) from 1985 to 1988. The addition of supplemental food resulted in a four-fold increase in population density in Douglas fir habitat and a two-fold increase in spruce habitat, indicating that populations in both habitats were food limited, but more strongly in Douglas fir habitat. The increase in density was the result of a strong increase in the recruitment of immigrants, primarily juveniles of unknown origin. Both recruitment to the food-supplemented grids and the decline in density following the removal of food were density-dependent. Stable population density may be the result of an inflexible territory size despite large changes in food abundance. To test this hypothesis, I monitored changes in territory size, home range size, the number of territories, intruder pressure, movement patterns and activity budgets in response to supplemental food. Supplemental food significantly decreased territory size and resulted in a five-fold increase in the number of territories in Douglas fir habitat. Territory size did not decrease in white spruce habitat, but there was a two-fold increase in the number of territories. In both habitats, immigrants established territories in previously unoccupied areas and in Douglas fir habitat, some immigrants established small territories on areas formerly used by residents who had defended large territories. There was an increase in the intensity that red squirrels travelled over their territories, a decrease in the proportion of time spent away from their territories and an increase in the proportion of time spent defending their territories. These behavioural changes appeared to offset the increased competitor density on the enriched territories, enabling red squirrels to defend territories larger than necessary for their current food requirements. This limited flexibility in territory size may reduce the amplitude of fluctuations in population density despite large changes in food abundance. Territorial behaviour can limit breeding density and juvenile recruitment. When territorial residents were removed from Douglas fir habitat in spring, red squirrel populations returned to a density similar to the control or pre-removal density in five of six removal trials. In autumn, population density returned to control or pre-removal densities in four of six trials. In white spruce habitat, population density returned to control or pre-removal levels in three of four trials in both spring and autumn. In both Douglas fir and spruce habitat, immigrants of unknown origin repopulated the removal areas. After removals in spring, females in breeding condition immigrated to the removal areas in five of six trials in Douglas fir habitat and in all four trials in spruce habitat. Settlement patterns did not appear to influence either territory size or recolonization density. / Science, Faculty of / Zoology, Department of / Graduate

North American red squirrels are a solitary, territorial species that confront various predators. Previous research proposed that squirrels produce predator-specific, referential ‘seet’ and ‘bark’ alarm calls to aerial and ground predators, respectively. To test this hypothesis, I examined alarm call production during natural encounters with predators, conspecific intruders and in a series of predator simulation experiments. Call production patterns were consistent across all types of disturbance and involved protracted bouts where both call types were inter-mixed. Hence, the call types were not predator-specific but rather their patterning reflected the persistence of disturbances of any type. Tests of alternative call functions further indicated that calls were not actually directed at conspecifics, but rather at predators and intruders and might function to deter or repel them directly. These outcomes are consistent with life-history details of red squirrels and contradict the proposal that this species produces predator-specific, referential alarm calls. / xi, 153 leaves : ill. ; 29 cm