The prey selection and predatory behaviour of a single pride of lions (Panthera leo) was studied in the 8500 ha Karongwe Game Reserve from 1999–2005. The study focused on the difference between prey selection in the first three years when a two-male coalition was present with a similar period thereafter when one of the males was removed and subadult males dispersed from the pride. A total of 662 kills were recorded, with blue wildebeest (Connochaetes taurinus), warthog (Phacochoerus africanus), waterbuck (Kobus ellipsiprymnus), zebra (Equus burchelli) and impala (Aepyceros melampus) being the most preferred species. Although there was preference for these species, and adult prey were favoured, there was no significant selection for prey size, age or gender. There was a significant difference in the number of kills made when the two-male coalition was present as opposed to the single pride male. The solitary pride male spent significantly more time with the females and shared most of their kills, and during this period dispersing subadult males killed a substantial amount of prey when separated from the pride. Knowledge on predator feeding behaviour is important for managers to assess impact on prey populations in small reserves in order to manage them correctly, thereby preventing depletion of such populations.

<p>Habitat fragmentation and anthropogenic development influence the level of isolation and security in and around protected habitats affecting wolf movements and the distribution and abundance of their prey. In light of recent concern about the ecology of animals in protected areas, I initiated a research project to investigate the molecular and foraging ecology of grey wolves in and around Prince Albert National Park (PANP), Saskatchewan. <p>Estimates of genetic diversity and population structure can be used as surrogates to detect effects of habitat degradation on wolves. Genetic diversity was high in these populations relative to other North American wolf populations. My results suggest that wolves in central Saskatchewan form a panmictic population, however there is some evidence showing partial isolation of one group of wolves within PANP. I speculate that the level of human activity such as road networks, hunting, and trapping act as dispersal impediments to this isolated group. Further, the genetic homogenization, indicating high population turnover, of wolf groups that use the periphery and adjacent areas of PANP may also contribute to the observed genetic subdivision. The partially isolated NW group, characterized by slightly lower diversity indices, low migration rates, and higher levels of allele fixation, indicated this group was a more stable social unit comprised of more related individuals.</p><p>Knowledge of wolf food habits and how they change over time is a fundamental component to understanding wolf ecology. Using scat analysis I evaluated wolf foraging ecology by calculating indices of occurrence/faeces (OF) and percent prey biomass contribution: white tailed deer contributed 43% and 33% respectively to wolf diet; elk (33%, 50%), moose (7%, 14%), beaver (5%, 2%), and snowshoe hare (2%, <1%). I found no evidence of livestock depredation nor did wolves prey on bison or caribou. There were no differences in OF indices between years. Prey selectivity was apparent in both years with wolves selecting elk and avoiding beaver. A diversity of ungulate prey are readily available to wolves in this system; however, scat analysis and tests for prey selection indicate a preference for elk. I presume this is a choice made to balance risk with profitability of food items in concordance with optimal foraging theory.</p><p>I examined trophic relationships between the grey wolf and 18 mammalian species from the boreal forest of central Saskatchewan, Canada, using ä13C and ä15N stable isotope values measured in hair samples. Variance in isotope values for wolves and other carnivores was investigated as a proxy for dietary variation. IsoSource, an isotopic source partitioning model, quantified the relative proportions of 5 most likely prey items in the diets of wolves.</p><p>I compared these results with investigations of faecal contents using percent biomass contributions of prey items in wolf diet. I found no difference between percent biomass measures and mean percent contributions derived from IsoSource. Despite social foraging, my results indicate highly variable diets among individual wolves and I discuss this in terms of boreal wolf ecology.

<p>Habitat fragmentation and anthropogenic development influence the level of isolation and security in and around protected habitats affecting wolf movements and the distribution and abundance of their prey. In light of recent concern about the ecology of animals in protected areas, I initiated a research project to investigate the molecular and foraging ecology of grey wolves in and around Prince Albert National Park (PANP), Saskatchewan. <p>Estimates of genetic diversity and population structure can be used as surrogates to detect effects of habitat degradation on wolves. Genetic diversity was high in these populations relative to other North American wolf populations. My results suggest that wolves in central Saskatchewan form a panmictic population, however there is some evidence showing partial isolation of one group of wolves within PANP. I speculate that the level of human activity such as road networks, hunting, and trapping act as dispersal impediments to this isolated group. Further, the genetic homogenization, indicating high population turnover, of wolf groups that use the periphery and adjacent areas of PANP may also contribute to the observed genetic subdivision. The partially isolated NW group, characterized by slightly lower diversity indices, low migration rates, and higher levels of allele fixation, indicated this group was a more stable social unit comprised of more related individuals.</p><p>Knowledge of wolf food habits and how they change over time is a fundamental component to understanding wolf ecology. Using scat analysis I evaluated wolf foraging ecology by calculating indices of occurrence/faeces (OF) and percent prey biomass contribution: white tailed deer contributed 43% and 33% respectively to wolf diet; elk (33%, 50%), moose (7%, 14%), beaver (5%, 2%), and snowshoe hare (2%, <1%). I found no evidence of livestock depredation nor did wolves prey on bison or caribou. There were no differences in OF indices between years. Prey selectivity was apparent in both years with wolves selecting elk and avoiding beaver. A diversity of ungulate prey are readily available to wolves in this system; however, scat analysis and tests for prey selection indicate a preference for elk. I presume this is a choice made to balance risk with profitability of food items in concordance with optimal foraging theory.</p><p>I examined trophic relationships between the grey wolf and 18 mammalian species from the boreal forest of central Saskatchewan, Canada, using ä13C and ä15N stable isotope values measured in hair samples. Variance in isotope values for wolves and other carnivores was investigated as a proxy for dietary variation. IsoSource, an isotopic source partitioning model, quantified the relative proportions of 5 most likely prey items in the diets of wolves.</p><p>I compared these results with investigations of faecal contents using percent biomass contributions of prey items in wolf diet. I found no difference between percent biomass measures and mean percent contributions derived from IsoSource. Despite social foraging, my results indicate highly variable diets among individual wolves and I discuss this in terms of boreal wolf ecology.

No description available.

Cougars (Puma concolor) have recently begun to reclaim former range and also are expanding into new territory. The Cypress Hills of southeast Alberta and southwest Saskatchewan now hosts the most eastern confirmed breeding population of cougars in Canada. However, with the return of cougars come new issues about human safety and risk of livestock depredation. Using GPS radiocollars, scat analysis, snowtracking and wildlife cameras, I found that the Cypress Hills boasts one of the highest densities of cougars ever reported, yet the large cats avoid human-use areas and have not been documented to prey on livestock. Using aerial ungulate survey data, I also show that the increase in cougar abundance is associated with a shift in distribution of nave ungulate prey to areas outside the park. Provided that cougars continue to avoid humans and cattle, this island habitat could prove to be an important stepping stone to further expansion eastward. / Ecology

The purpose of this study was to examine the hunting strategies of birds of prey in a probability learning situation. One great horned owl and one red-tailed hawk served as subjects. Three boxes and associated perches, each representing different potential prey areas, were placed in a room adjacent to the birds' regular housing and served as test apparatus. One box were required to land on a perch in order to gain access to the associated box and to the potential prey. A discrete-trial, self-correction procedure was used. In Experiment I, Box 1 was loaded with a live laboratory mouse on 60% of the trials, Box 2 on 30% of the trials, and Box 3 on the remaining 10%. A response requirement of sitting on the perch 5 seconds was programmed. In experiment II, the probability of reinforcement was reversed for the 10 and 60% boxes and the response requirement was increased from 5 to 20 seconds. Experiment III returned the probability of reinforcement for each box to the values used in Experiment I. In Experiment III the mice were euthanized prior to each trial. The owl matched responses to probability of reinforcement in all three experiments while the hawk matched in Experiment II and showed matching toward two of the three boxes in Experiment III. In Experiment I the hawk had a Box 2 preference. This research extends the generality of the matching concept and suggests that predatory birds do not randomly hunt or hunt in only one location, but rather tend to search according to the probability of reinforcement for that location.

Abstract In this thesis I studied lotic trout predation and its ecological effects, and investigated invertebrate predator-prey interactions under natural and anthropogenically modified flow conditions. Given the growing concern about the reliability of extrapolations from small-scale studies to larger spatio-temporal scales, results of mechanistic small-scale experiments were scaled up by linking them to large-scale field surveys. An intensive survey assessed changes in diel feeding periodicity, prey selection and daily ration of juvenile brown trout (Salmo trutta L.) over the course of the open water period. This survey provides the first field estimates of juvenile brown trout daily rations and indicates crepuscular feeding peaks. Trout selectively preyed on medium- to large-sized prey, shifting towards epibenthic feeding with increasing availability of suitable prey. In a small-scale field experiment, trout displayed clear size-related predation concentrating on invertebrate predators and cased caddisflies, a pattern that scaled up successfully in large-scale surveys. Further, predation effects on large-sized prey were also repeated in a meta-analysis on lotic salmonid predation. While dense blackfly populations in lake-outlet streams are common, mass outbreaks of blackflies in short-term regulated rivers are poorly studied. In our studies the principal invertebrate predator of vernal benthic communities, the caseless caddisfly Rhyacophila, displayed significant preference for blackflies and was almost unable to capture any other prey, thus resulting in passive selection for larval blackflies. Rhyacophila larvae displayed highest capture success in intermediate current velocities, whereas further increases in current velocities decreased capture success. Short-term regulation releases increased both predator and prey drift but, unlike for Rhyacophila, magnitude of drift was unrelated to substrate for blackflies. Indeed, field observations indicated that blackflies rarely face detrimental effects of short-term regulation due to their fast growing rates and early emergence. Moss was the most preferred habitat of Rhyacophila and provided the best buffer against sudden increases in current velocities. These results suggest that several factors maintain spring-time outbreaks of blackfly populations in short-term regulated rivers: exaptation of the dominant blackfly species to prevailing conditions, degradation of the key habitat of the predator, and recurring annual drift losses and diminished capture success of Rhyacophila during short-term regulation releases.

Early in the 20th century wild turkeys (Meleagris gallopavo) in North America were on the brink of extinction. Conservation and reintroduction efforts ensured that this species recovered throughout most of its historic range. Efforts to reintroduce eastern wild turkeys (Meleagris gallopavo sylvestris) to the Pineywoods of east Texas have achieved limited success. Previous research suggested that predation may have confounded this reintroduction. My aim was to quantify the influence of mesopredators on the wild turkey population in the Pineywoods. Raccoons (Procyon lotor), bobcats (Lynx rufus) and coyotes (Canis latrans) occur sympatrically in east Texas and are thought to prey on wild turkeys, their nests and poults. I fitted bobcats, coyotes and raccoons with both GPS and VHF collars and used location data and GIS applications to estimate home ranges, home range overlap and habitat selection for these mesopredators. I used scat analysis to determine diet of mesopredators and to establish whether they preyed on wild turkeys. I used capture mark recapture (CMR) techniques to investigate small mammal population dynamics at annual and seasonal bases. I used spotlight counts and track plates to assess seasonal relative abundance of eastern cottontail rabbits (Sylvilagus floridana). I used artificial nests to identify likely nest predators of wild turkey nests. I found that mesopredators in the Pineywoods had larger home ranges than elsewhere in the Southeast. Bobcat and coyote home ranges varied seasonally, being largest in fall. Raccoon home ranges did not vary seasonally. Bobcats and coyotes shared space more than did raccoons with bobcats or coyotes. There was differential habitat selection between species, but mature pine and young pine were important to the mesopredators and as nesting habitat for eastern wild turkeys. I found no evidence of wild turkey remains in scat samples. White tailed deer (Odocoileus virginianus), lagomorphs and small mammals occurred in the diets of all three mesopredators. Small mammal numbers varied seasonally, declining from spring to summer, in synchrony with mesopredator diet diversification, and wild turkey nesting and brood rearing. Lagomorph abundance did not vary seasonally. Bobcats were predominantly carnivorous while coyotes and raccoons were omnivorous, consuming seasonal fruit and insects. American crows (Corvus brachyrhynchos) and raccoons were the primary artificial nest predators. Crows depredated most artificial nests, except in summer, when raccoons depredated the most nests. I concluded that the impact of mesopredators on wild turkeys was not as severe as suggested by previous research. I suggest a combination of video monitoring live wild turkey nests to identify nest predators, improvement of nesting habitat to reduce mesopredator / wild turkey nest encounters, and a program of conditioned taste aversion to reduce any nest predation by mesopredators and crows.

No description available.

Made available in DSpace on 2017-07-10T18:13:13Z (GMT). No. of bitstreams: 1 Ariane Furtado de Lima.pdf: 1547772 bytes, checksum: 2b187bf1d3cfbc9d8257e7d583283199 (MD5) Previous issue date: 2013-03-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The effects of feeding privation on growth of larvae of jundiá Rhamdia voulezi as well as the feeding preference during larval period were evaluated. For this purpose two experiments were conducted which began soon after complete absorption of the yolk sac, the fourth day after hatching (DAH). The feeding privation experiment was performed in 8 treatments consisting of different diets, including the control treatment (CT) in which there was no food supply. The food was provided for the first time in the 4th, 5th, 6th, 7th, 8th, 9th and 10th DAH corresponding to treatments: T4, T5, T6, T7, T8, T9 and T10, respectively. The food consisted of zooplankton and newly hatched artemia. We performed 3 trials of selectivity to analyze the feeding preference throughout the larval period, comprising different larval stages and classes of standard length. In this, the larvae were fed exclusively on zooplankton collected from fish ponds. The results demonstrated that the larvae fed on the fourth to sixth DAH had a significantly higher growth than those fed later, from the seventh DAH. The point of no return was recorded in the same period in the 7th DAH. With respect to feeding selectivity, there were variations in the patterns of prey selection in different days of life analyzed. Initially on the 5th DAH, preflexion stage, larvae strongly selected rotiferas (unidentified) and cladocerans (Diaphanosoma spinulosum, D. brevireme, Moina sp., M. micrura, M. minuta). In the remaining days of life examined, the cladocerans continued to be strongly selected. However on the 8th DAH, flexion stage, they selected less intensely the copepods Argyrodiaptomus azevedoi and Termocyclops decipiens and more strongly A. furcatus, Notodiaptomus spinuliferus and Metacyclops mendocinus at 10 DAH, postflexion stage. The delay of the first feeding drastically affected the growth of the larvae, and that if feeding is started before the point of no return there are chances of recovery. So, it is important to have suitable availability of food, with a variety of type and size so that they can compensate for the morphological limitations of larvae in the early of their development. Concomitant to its growth, the larvae tend to specialize in certain prey items. The size of prey consumed is related to the size of the larvae and the gape size. Initially larvae have a preference for smaller prey, rotifers and cladocerans, and later when they are more developed prefer to feed on larger prey, the copepods. / Neste estudo foram avaliados os efeitos da privação alimentar sobre o crescimento das larvas de jundiá Rhamdia voulezi bem como a preferência alimentar durante o período larval. Para isto foram realizados dois experimentos que tiveram início logo após a absorção completa do saco vitelínico, que ocorreu no 4o dia após a eclosão (DAE). O primeiro experimento de privação alimentar foi realizado com 8 tratamentos constituídos por diferentes regimes alimentares, incluindo o tratamento controle (TC) no qual não houve fornecimento de alimento. O alimento foi fornecido pela primeira vez no 4o, 5o, 6o, 7o, 8o, 9o e 10o DAE, correspondendo aos tratamentos: T4; T5, T6, T7, T8; T9 e T10, respectivamente. A alimentação consistiu de zooplâncton e artêmia recém-eclodida. Para avaliar a preferência alimentar, foram realizados 3 ensaios de seletividade alimentar ao longo de todo o período larval, compreendendo diferentes estágios de desenvolvimento e classes de comprimento padrão. Neste, as larvas foram alimentadas exclusivamente com zooplâncton coletado de tanques de cultivo. Os resultados demonstraram que as larvas de jundiá que receberam alimento do 4o ao 6o DAE tiveram desenvolvimento significativamente maior que aquelas alimentadas mais tardiamente, a partir do 7o DAE. O ponto de não retorno foi registrado neste mesmo período, no 7o DAE. Com relação à seletividade alimentar, houve variações nos padrões de seleção de presas nos diferentes dias de vida analisados. Inicialmente no 5o DAE, estágio de pré-flexâo, as larvas selecionaram fortemente os rotiferas (não identificados) e os cladoceras (Diaphanosoma spinulosum, D. brevireme, Moina sp., M. micrura, M. minuta). Nos demais dias de vida analisados, os cladoceras continuaram a ser fortemente selecionados. Entretanto no 8o DAE, estágio de flexão, selecionaram menos intensamente os copepodas Argyrodiaptomus azevedoi e Termocyclops decipiens e no 10o DAE, estágio de pós-flexão, consumiram especialmente Argyrodiaptomus furcatus, Notodiaptomus spinuliferus e Metacyclops mendocinus. Conclui-se que o retarde da primeira alimentação afeta drasticamente o crescimento das larvas, e que, se a alimentação for iniciada antes do ponto de não retorno há chances de recuperação e sobrevivência larval. Para isto, é importante que haja disponibilidade adequada de alimento, com variedade de tipo e de tamanho de modo que possam compensar as limitações morfológicas das larvas no início do seu desenvolvimento. Concomitante ao seu crescimento, as larvas tendem a se especializar em determinados itens presa, existindo uma seleção de presas tanto pelo tipo como também pelo tamanho, onde o tamanho da presa consumida está relacionado com o tamanho da larva e o tamanho de sua boca. Inicialmente as larvas de jundiá têm preferência por itens presas menores, os rotíferos e cladoceras, posteriormente, quando estão mais desenvolvidas, preferem alimentar-se de presas maiores, os copepodas.