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. 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.

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 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

Thesis (M.Sc.)--Memorial University of Newfoundland, 1997. / Bibliography: leaves 78-87.

Natal dispersal is at the nexus of ecology, ethology, population genetics, and evolution. While abundant research exists on emigration and associated proximate and ultimate causes, less is known about exploration, settlement, and factors that influence settlement decisions. Further, the role of individual behavioral phenotypes in the domains of wildlife ecology and conservation, which include natal dispersal, is a recent and expanding area of inquiry. Understanding the relationships among individual phenotype, environmental conditions, and natal dispersal is increasingly important as landscapes become altered by disturbance, fragmentation, and climate change. I investigated natal dispersal in endangered Mt. Graham red squirrels (Tamiasciurus hudsonicus grahamensis), an isolated, peripheral subspecies of North American red squirrel persisting at the southern edge of the species' range. We tested hypotheses about the importance of proximate and ultimate drivers of emigration, dispersal distance, and settlement, and estimated perceived landscape connectivity within a mosaic of forest damage in the Pinaleño Mountains, Arizona. Compared to other red squirrel populations in North America, natal dispersal in Mt. Graham red squirrels is sex-biased and non-philopatric with mean dispersal distance over 8 times that observed in non-peripheral populations. Resources, indicated by mother's body mass in spring (a reflection of her intrinsic quality and territory quality) and individual body condition, contribute to individual behavioral tendencies for movement and exploration. Individuals with behavioral tendencies for movement and exploration dispersed the farthest, and for both males and females the longest observed dispersal distances and proportion of individuals dispersing occurred in a year of lowest food availability. Our research highlights the important role individual behavioral syndromes may play in observed heterogeneity in life history strategies with populations. Following emigration from the natal area, we provide evidence that individual dispersers rely upon forest structural cues similar to their natal area to select locations for settlement; the first test of natal habitat preference induction in a single vegetation community type. We used circuit theory to evaluate landscape connectivity and identify areas important for long-distance dispersal movements. Because single connectivity models may not adequately represent functional connectivity for an entire population, we summarized landscape connectivity across varying levels of landscape resistance to identify areas that promote movement and long-distance dispersal for individuals with different perceptions of landscape resistance. We show that composite connectivity models are a useful method to identify forest areas important for the promotion of long-distance movements as well as areas that constrain movement.

Natal dispersal outcomes are an interplay between environmental conditions and individual phenotypes. Peripheral, isolated populations may experience altered environmental conditions and natal dispersal patterns that differ from populations in contiguous landscapes. We document nonphilopatric, sex-biased natal dispersal in an endangered small mammal, the Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis), restricted to a single mountain. Other North American red squirrel populations are shown to have sex-unbiased, philopatric natal dispersal. We ask what environmental and intrinsic factors may be driving this atypical natal dispersal pattern. We test for the influence of proximate factors and ultimate drivers of natal dispersal: habitat fragmentation, local population density, individual behavior traits, inbreeding avoidance, competition for mates, and competition for resources, allowing us to better understand altered natal dispersal patterns at the periphery of a species' range. A juvenile squirrel's body condition and its mother's mass in spring (a reflection of her intrinsic quality and territory quality) contribute to individual behavioral tendencies for movement and exploration. Resources, behavior, and body condition have the strongest influence on natal dispersal distance, but affect males and females differently. Male natal dispersal distance is positively influenced by its mother's spring body mass and individual tendency for movement; female natal dispersal distance is negatively influenced by its mother's spring body mass and positively influenced by individual tendency for movement. An apparent feedback between environmental variables and subsequent juvenile behavioral state contributes to an altered natal dispersal pattern in a peripheral population, highlighting the importance of studying ecological processes at the both range center and periphery of species' distributions.