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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Social learning and social behaviour in two mixed-species communities of tufted capuchins (Sapajus sp.) and common squirrel monkeys (Saimiri sciureus)

Messer, Emily Jane Elizabeth January 2013 (has links)
Primates are known for being highly social species, living in groups of various compositions with different social structures. The study of social or observational learning has largely focussed on investigating non-human primates' abilities to imitate, with a more recent shift towards examining the social context of social learning. This shift has presented opportunities to investigate how the social context of different species affects the diffusion of socially learnt behaviours. In this thesis, I set out to monitor the spread of different experimentally seeded and naturally occurring socially learned behaviours in brown (tufted) capuchin monkeys (Sapajus sp.) and common squirrel monkeys (Saimiri sciureus).These species were selected as they form mixed species groups in the wild, and display marked differences in their social tolerances, thus presenting the opportunity to investigate conspecific and heterospecific social learning in related but differently bonded social groups. My results show evidence of social learning from conspecifics in capuchin and squirrel monkeys, attesting to that already documented in capuchin monkeys and indicating for the first time, that common squirrel monkeys can learn socially. Additionally, I demonstrate that capuchin monkeys are influenced by squirrel monkeys when foraging for food in mixed species groups. Furthermore, although squirrel monkeys are not as socially tolerant as capuchin monkeys, individuals who were better connected within the foraging test area learned experimentally-seeded techniques of models faster and more faithfully. When performing socially contagious anointing behaviours, regardless of tufted capuchin monkeys being influenced by the amount of resources provided for them to anoint with, they still performed more socially anointing than has been previously documented in other captive species, corroborating the levels of social anointing demonstrated in semi-free ranging groups. Further support was found for anointing demonstrating a social bonding and medicinal function in tufted capuchin monkeys.
112

Ecological politics and practices in introduced species management

Crowley, Sarah Louise January 2017 (has links)
The surveillance and control of introduced species has become an increasingly important, yet often controversial, form of environmental management. I investigate why and how introduced species management is initiated; whether, why and how it is contested; and what relations and outcomes emerge ‘in practice’. I examine how introduced species management is being done in the United Kingdom through detailed social scientific analyses of the processes, practices, and disputes involved in a series of management case studies. First, I demonstrate how some established approaches to the design and delivery of management initiatives can render them conflict-prone, ineffective and potentially unjust. Then, examining a disputesurrounding a state-initiated eradication of monk parakeets (Myiopsitta monachus), I show why and how ‘parakeet protectors’ opposed the initiative. I identify the significance of divergent evaluations of the risks posed by introduced wildlife; personal and community attachments between people and parakeets; and campaigners’ dissatisfaction with central government’s approach to the issue. By following the story of an unauthorised (re)introduction of Eurasian beavers (Castor fiber) to England, I show how adiverse collective has, at least temporarily, been united and empowered by a shared understanding of beavers as ‘belonging’ in the UK. I consider how nonhuman citizenship is socio-politically negotiated, and how the beavers have become enrolled in a ‘wild experiment’. Finally, through a multi- sited study of grey squirrel (Sciuruscarolinensis) control initiatives, I find important variations in management practitioners’ approaches to killing squirrels, and identify several ‘modes of killing’ that comprise different primary motivations, moral principles, ultimate aims, and practical methods. I identify multiple ways in which people respond and relate to introduced wildlife, and demonstrate how this multiplicity produces both socio-political tensions and accords. Furthermore, throughout this thesis I make a series of propositions for re-configuring the management of introduced species in ways that explicitly incorporate inclusive, constructive, and context-appropriate socio-political deliberations into its design and implementation.
113

Return of Historical Fire: Impacts of Burn Severity and Heterogeneity on Mexican Fox Squirrels

Doumas, Sandra L. January 2010 (has links)
After decades of suppression, fire is returning to forests of western United States. Understanding responses of wildlife species to fire is essential to native species conservation because contemporary fires may not have the same effects on forest structure and landscape patterns as historical fires. I used radio-telemetry to investigate effects of fire severity and heterogeneity on habitat selection of Mexican fox squirrels, Sciurus nayaritensis chiricahuae. Vegetation within home ranges was characterized by more open understory and larger trees than random locations. Squirrels used areas burned at low severity more than unburned areas and those burned at higher severities. Squirrels used areas of moderate burn heterogeneity more than areas of low or high heterogeneity. Return of low-severity fire can help restore habitat for Mexican fox squirrels and other native species in forests with a historical regime of low-severity fire and contribute to understanding of the role of fire in forest ecosystems.
114

Reproductive success of round-tailed ground squirrels

Hardy, Danita Sue, 1957- January 1987 (has links)
I studied round-tailed ground squirrels (Spermophilus tereticaudus) to determine if presence of water or green vegetation significantly increased reproductive success. I compared the number of juveniles produced, body weights, and diets of squirrels during 1981-84 on 2 plots with green vegetation and no free water, on 3 plots with free water and no green vegetation, and 2 control plots. Reproductive success and body weights of adult and juvenile squirrels were significantly higher (P ≥ 0.001) on plots with green vegetation than on either watered or control plots. Body weights of squirrels on plots with water only and control plots were not significantly different (P ≥ 0.05). Adult squirrels without access to green vegetation during winter and spring failed to reproduce even though free water was readily available. Percent of diet overlap, diversity, and evenness of squirrel diets on control and watered plots were not significantly different. Green vegetation appeared to be the limiting factor for round-tailed ground squirrels.
115

CHARACTERISTICS OF PONDEROSA PINE STANDS SELECTED BY THE ABERT'S SQUIRREL FOR COVER

Patton, David R. January 1974 (has links)
No description available.
116

Behavior and Ecology of Neotropical Tree Squirrels in Seasonally Flooded Forests in the Peruvian Amazon

Jessen, Rosa Raquel January 2013 (has links)
Tree squirrels play an important role in the maintenance of forest ecosystems by functioning as seed and fungal spore dispersers, forest regenerators, and prey for forest predators. The highest species richness for tree squirrels occurs in tropical forests and these species are also the least studied. We conducted distance sampling to estimate population density, measured habitat variables to investigate forest characteristics that influence habitat selection and feeding site selection at three different scales, and conducted observations to obtain knowledge about activity pattern and behavior of Neotropical pygmy squirrels and Amazon red squirrels in the Peruvian Amazon. Density of Neotropical pygmy squirrels was 0.10 and 0.14 individuals/ha for 2009 and 2010. Activity peaked in early morning, squirrels were found mainly in the canopy but never on the ground, and frequency of behaviors differed by time and story level. Neotropical pygmy squirrels used mainly high and low restinga and areas that had more large trees. Squirrels also used species of trees disproportionately to availability. Neotropical pygmy squirrels seem to be associated with features related to mature forests. Amazon red squirrels use mainly high and low restinga and selected Astrocaryum and Attalea palm trees that were taller and larger as foraging sites compared to random locations. Amazon red squirrels used all vertical strata of the forest and the main behaviors observed were travel and forage. Behaviors were similar among time periods but differed in frequency by vertical strata. Although Amazon red squirrels used vegetation communities differently than their availability and selected for tree characteristics, they did not select for site characteristics and this is different from other tree squirrel species. We also conducted surveys during a wet and a dry year to investigate and estimate diversity of diurnal mammals. We assessed the vertical strata of the forest to determine if diversity index varied by story level, and estimated alpha, beta, and gamma diversity. Overall mammal diversity did not differ between wet and dry years. Diversity index differed by story level between years, but was the highest in the canopy for both years. Alpha diversity was higher in the dry year, and gamma and beta diversity were higher in the wet year. Frequency of sightings of species was influenced by time of day and varied by story level. Protection of continuous, mature forests with large canopies has important conservation implications as these areas most likely protect the greatest diversity of mammals while also providing shelter and food for other taxa.
117

Do Red Squirrel Middens Promote Vertebrate Species Diversity?

Posthumus, Erin Elizabeth January 2013 (has links)
The modifications animals make to their environments can be critical to species diversity. Red squirrels (Tamiasciurus hudsonicus) create large piles of conifer cone debris (middens) and are hypothesized to function as a keystone species due to positive associations between middens and other vertebrate species. We assessed vegetation and landscape structure at middens with a resident red squirrel for varying consistencies over the prior 5 years and surveyed mammals and birds at the community and population level. After accounting for vegetation and landscape characteristics, red squirrel-created resources positively influenced species richness of medium and large mammals and ground foraging birds, abundance of deer mice (Peromyscus maniculatus) and ground foraging birds, and activity of cliff chipmunks (Tamias dorsalis). Increased knowledge of the interaction strength of the red squirrel with its environment may be used to inform decisions in forest management and restoration and offer insight on the conservation value of larderhoarding mammals.
118

Mother-infant separation in squirrel monkeys living in a group

Jones, Byron Clarence, 1944- January 1972 (has links)
No description available.
119

Snake harassment in the Cape ground squirrel (Xerus inauris): variation in anti-predator behaviours, predator discrimination and venom resistance in a facultative cooperative breeder.

Phillips, Molly A. 06 1900 (has links)
Predator harassment is an anti-predator behaviour that may increase a harasser’s risk of predation but decrease the potential for predation for other members of a group. The Cape ground squirrel (Xerus inauris) is a facultative cooperative breeder from southern Africa that harasses venomous snakes. The objective of my study was to examine predator harassment to determine: 1) whether predator harassment was part of alloparental care by comparing harassment behaviour among age and sex classes; 2) how individuals adjusted their behaviour against different snake species; 3) whether olfaction was used in discrimination of snakes; and 4) if individuals possessed venom resistance against venomous snakes. I found that females with juvenile offspring harass snakes longer and more intensely than other individuals, suggesting that predator harassment was a maternal behaviour. Squirrels increased harassment, inspection and vigilant behaviours with risk when exposed to both live snakes and snake odours suggesting they can use olfaction to discriminate snake predators. I also found no venom resistance in Cape ground squirrels concluding the cost of envenomation was significant.
120

Snake harassment in the Cape ground squirrel (Xerus inauris): variation in anti-predator behaviours, predator discrimination and venom resistance in a facultative cooperative breeder.

Phillips, Molly A. 06 1900 (has links)
Predator harassment is an anti-predator behaviour that may increase a harasser’s risk of predation but decrease the potential for predation for other members of a group. The Cape ground squirrel (Xerus inauris) is a facultative cooperative breeder from southern Africa that harasses venomous snakes. The objective of my study was to examine predator harassment to determine: 1) whether predator harassment was part of alloparental care by comparing harassment behaviour among age and sex classes; 2) how individuals adjusted their behaviour against different snake species; 3) whether olfaction was used in discrimination of snakes; and 4) if individuals possessed venom resistance against venomous snakes. I found that females with juvenile offspring harass snakes longer and more intensely than other individuals, suggesting that predator harassment was a maternal behaviour. Squirrels increased harassment, inspection and vigilant behaviours with risk when exposed to both live snakes and snake odours suggesting they can use olfaction to discriminate snake predators. I also found no venom resistance in Cape ground squirrels concluding the cost of envenomation was significant.

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