Thesis (M. Sc.)--Memorial University of Newfoundland, 1997. / Bibliography: leaves 44-51.

Abstract Relationships between predators and prey may affect population dynamics of both parties. Predators may also serve as a link between populations of different prey, e.g., small game and small mammals. I used available data on the diet and reproduction of birds of prey (mainly common buzzards Buteo buteo and goshawks Accipiter gentilis) and video surveillance of their nests, as well as multiannual data on numbers of grouse and small mammals for studying food habits and population dynamics of raptors and their links with population fluctuations of voles and grouse (capercaillie Tetrao urogallus, black grouse Tetrao tetrix and hazel grouse Bonasa bonasia) in western Finland during 1980–1990s when grouse and vole numbers fluctuated in regular cycles. Microtus voles were the main prey of the buzzards which partly switched their diet to small game (juvenile grouse and hares) in years when vole numbers declined. The nesting rate of buzzards also correlated with vole abundance, but the productivity rate and brood size tended to lag behind the vole cycle. This mismatch between the buzzards' functional and numerical responses resulted in a fairly small impact of buzzards on juvenile grouse, which did not correlate with vole density. The productivity of goshawks followed the fluctuations of grouse density closely whereas the occupancy rate of goshawk territories did so with a two-year lag. The annual numerical ratio of goshawk to grouse was inversely related to grouse density, suggesting that this predator may be a destabilising factor for grouse population dynamics. However, the goshawks' kill rate of grouse showed no clear relations to grouse density. In June–July, these birds of prey (including hen harriers Circus cyaneus) usually killed a relatively small number of grouse chicks. Losses to raptors constituted up to one quarter of grouse juvenile mortality during the two months. We did not find a strong effect of avian predators on grouse juvenile mortality. In boreal forests, predators and other factors of grouse mortality do not operate as one, and there is probably no single factor responsible for the reproductive success of grouse.

This study is an analysis of the various factors affecting the population of raptorial birds on Sauvie Island, Oregon. A census of diurnal and nocturnal raptors was carried out along with an analysis of food habits. Once the major prey species were determined they were censused, and the effects of the land management practices on their numbers was investigated. In addition, 100 randomly selected nest boxes were sampled so as to determine the extent to which raptors were making use of them. Red-tailed hawk and Great Horned Owl nests were located It was found that four diurnal raptors and three nocturnal raptors were present in sizeable numbers on Sauvie during the winter and spring of 1972. In addition here were less common sightings of four diurnal and one nocturnal raptor. The most common food item of raptors in general was the vole, Microtus townsendi, which was later found to be present in extremely high numbers. The common practice of planting fields of grains and the intentional flooding of them (for waterfowl use) was found to be a major factor in the numbers and vulnerability of Microtus townsendi. Ducks were a common food item for all raptorial species during and immediately after duck hunting season, but not at any other time of year which seemed to indicate that the raptors were feeding on carrion or wounded ducks. It was found that Barn Owls (Tyto alba), Screech Owls (Otis asio) and Kestrel (Falco sparvarius) made use of the nest boxes on Sauvie Island. The overlapping of food habits of Sauvie Island raptors was discussed and an attempt was made to reconcile the apparent contradiction to Gause’s Rule.

No description available.

Plastic pollution is unavoidable in the natural environment. Consequences of plastic ingestion include exposure to environmental pollutants and toxin accumulation, causing endocrine disruption, inflammatory and physiological stress in organisms. Microplastics have been shown to transfer across food webs, however, limited studies have examined microplastic accumulation across terrestrial food webs. Furthermore, few studies have examined plastic pollution in apex predatory animals. A study was conducted to quantify the abundance of plastic pollution in the gastrointestinal tract in birds of prey. Two species were investigated, one which forages in terrestrial habitats and one which forages in aquatic environments including Buteo lineatus (red-shouldered hawk) and Pandion haliaetus (osprey), respectively. The gastrointestinal tract was necropsied, chemically digested, and examined for microplastic prevalence. Overall, microplastics are significantly more abundant per gram of gastrointestinal (GI) tract tissue in species that forage on small rodents and terrestrial reptiles (B. lineatus) as compared to species that forage on fish and aquatic invertebrates (P. haliaetus). Buteo lineatus averaged 0.81 (±0.15) fibers and 0.14 (±0.04) fragments per gram of GI tract tissue while P. halieatus averaged 0.31 (±0.09) fibers and 0.04 (±0.02) fragments per gram of GI tract tissue. There was a significant interaction between type and color in both B. lineatus and P. haliaetus GI tract tissues. Micro-Fourier-transform infrared spectroscopy (μ-FTIR) was run on haphazardly selected samples and found that rayon was the most common polymer identified in both species. The significant difference found between species could be indicative that terrestrial raptors may experience greater bioaccumulation than aquatic species foraging at comparable trophic levels. However, the significant interaction between type and color in both species indicates a potential common source of pollution that affects both environments. Further investigation on the source of polymers is necessary in order to develop conservation and management strategies aimed at decreasing the output of synthetic fibers into the environment. Due to the abundance of polymers found in these species, understanding the potential biological and physiological effects of plastics is essential to informing superior management strategies that can better protect and preserve wildlife from increasing anthropogenic pressures.

Wildlife trade is a significant factor affecting situation of some species in the wild. Especially its illegal part, which is also very profitable similarly as arms trade and drugs trade, may be fatal for some species. Today, birds of prey are one of the most often traded groups of birds in the world and falconry is the main driving force of this trade. Although development of methods of captive breeding of birds of prey was an important turning point for their protection, it was not able to fully suppress taking them from the wild. Until recently, the European market was a large consumer of imported birds but European Union policy makes imports, especially for wild birds, more and more difficult. Thus it supports another aspect which is historically rooted in this area, namely breeding. A keeping and captive breeding of birds of prey is increasing in Europe and it takes part in global market. The goal of this thesis was to analyse content and volume of the trade with live specimens of birds of prey within EU for period 2000-2017. In addition to the EU as a whole, data for the Czech Republic were also processed. The EU has proven to be an important exporter with an upward trend, whereas imports have been restricted, especially since 2006, and still decrease. In general, the most traded birds are hybrid falcons and also a Gyrfalcon which is determined by Middle East demand. Although there are almost only captive birds in European export, there still are wild birds in some imports, especially vultures from Guinea. The Czech Republic copies European trends more or less. It seems that there is more birds of Accipitriformes order in the intra-European trade than in the trade with third countries. It emerged that European legislations can have a significant impact on the trade, even in global terms. An unpleasant finding was that used sources (especially the CITES database) have to be taken with discretion because they contain many mistakes and inconsistencies which may dramatically affect the results.

Rodent densities were estimated in the major vegetation types of the Snake River Birds of Prey Natural Area in 1975 and 1976 by a combination of live-trapping and kill-trapping. Only deer mice (Peromyscus maniculatus) were numerous enough to permit reliable density estimates. Relative densities of other rodent species were indicated by kill-trap capture rates. Densities of deer mice correlated well (r = 0.99) with kill-trap capture rates. The use of kill -trapping in place of live-trapping in 1976 permitted extensive sampling throughout the 1930 km2 study area. Differences were found among the major vegetation and land-use types in their ability to support the rodent species representing potential prey for feeding raptors.

This dissertation describes the development of a new sustained release formulation of nifedipine. The new formulation was developed by coating commercially available immediate release soft elastic gelatin capsules using a spray coating technique with two different polymeric combinations. Dissolution studies were conducted and showed that controlled release of nifedipine was obtained by increasing the ratio of the water insoluble polymer in the coat and increasing the percent weight gain of the coating. Simulated plasma concentration versus time profiles after administration of 30 mg dose of selected formulations showed a prolonged nifedipine release with concentrations above the minimum effective concentration for up to 12 hours. Bioavailability and bioequivalence of tableted test formulation of verapamil HCL was determined in 8 volunteers and compared to Covera HS® under fed and fasting conditions. The 90% confidence intervals for individual percent ratios of the Cmax, AUC₀₋₅₈ and AUC₀ were not within the range of 80 - 125% in both fed fasted states, suggesting that these formulations are not bioequivalent. the bioavailability of verapamil from the new formulation was higher state but this effect was not statistically significant. Pharmacokinetics of terbinafine administered orally at single doses of 15, 30, 60 and 120 mg were determined in raptors to recommend an appropriate dosing scheduled for terbinafine in the treatment of Aspergillosis. Calculation of steady state trough terbinafine plasma concentration after administration of daily doses of 15 or 30 mg/day showed that 30 mg daily dose of terbinafine administered orally in raptors produces a steady state trough terbinafine plasma concentration above the minimum inhibitory concentration (MIC) of(0.8 1.6) µg/ml against aspregillus fumigatus. From the data, 30 mg per day oral dose of terbinafine should be the recommended dose for treatment of aspergillosis in raptors. Approximate pharmacokinetic linearity of terbinafine was demonstrated for AUC[subscript 0-t] in the dose range of 15 120 mg while non-linearity for Cmax in the same dose range was demonstrated using the power model. / Graduation date: 2005

Thesis (M.S.)--University of Montana, 2004. / Includes bibliographical references (leaves 85-88). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M.S.)--University of Montana, 2004. / Includes bibliographical references (leaves 85-88).