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Palaeo-ornithology has been dominated by taxonomy. To try and redress the balance and help palaeoecologists interpret fossil birds in a biological and ecological perspective, the taphonomy of birds needs to be fully understood. The taphonomy of birds is concerned with all processes from death to the collection of the fossil bird. Between these two points (the transfer of the organism from the biosphere to the lithosphere) a variety of forces and processes affect the bird/fossil. By means of experiments in the natural environment and in controlled conditions in the laboratory, and subsequent comparisons of the results with case studies of fossil assemblages, the processes leading to preservation can be deduced and the former living community restored on the basis of the fossil evidence. The research involved two main approaches: 1. experimental taphonomy / observational taphonomy; and 2. case histories of fossil communities and their interpretation. Experimental work was carried out in the natural environment. Two field sites were chosen in southern Florida, a freshwater environment and a marine environment. The monitoring and controlling of these experiments required knowledge and techniques in zoology, botany, ecology, sedimentology, limnology, marine biology, microbiology, pathology and forensic science. Results obtained included the effects of scavenging, anoxia, transport, rate of burial, and temperature on rates of decay, the causes of bird mortality, the processes resulting in disarticulation, and the effects of decay upon feathers. Once the experimentaVobservational data had been collected they allowed a series of taphonomic thresholds (a decay sequence) to be defined. These data were then applied to case studies of fossil bird assemblages from different sedimentological environments. The following LagersHitten were investigated: Messel (Eocene, Germany) = restricted lacustrine; Green River (Eocene, USA) = lacustrine; Solnhofen Lithographic Limestone (Jurassic, Germany) = restricted marine; La Meseta Formation (Eocene, Antarctica) = marine; Rancho La Brea (Pleistocene, USA) = terrestrial "trap". The biases in each environment were assessed (e.g. birds in an aquatic ten-estrial environment had a higher preservation potential than birds from a tenestrial environment). The fossil record of birds is not as depauperate as previously thought but is heavily biased, depending on the proximity of the bird's habitat to that of the preserving sedimentary environment. Marine and littoral birds are poorly represented even though they inhabit sedimentary environments with a high preservation potential. This reflects low densities of birds per unit area. Aquatic birds (and terrestrial birds that inhabit the ecotone surrounding freshwater together with some larger fOlIDS from further away) are much better represented. This is because they inhabit the only terrestrial environments with a high preservation potential, coupled with the high densities of individuals per unit area. The bias towards large terrestrial birds is due to their large bones being more resistant to transport induced damage. These results have implications for the understanding of the evolution of birds. Patterns of evolution in birds can not be fully resolved on fossil evidence alone; biases in the taphonomy of birds only permit a small proportion of species from certain environments to be preserved. The taphonomy of feathers was investigated and it was discovered that the "organic trace" that commonly represents the outline of the feather trace is the diagenetically altered glycocalyx of the bacteria that were degrading the feather. In several localities these feather-degrading bactelia are preserved in authigenic minerals. The taphonomy of bats and pterosaurs was also investigated. The similarity of anatomical structures of birds, bats and pterosaurs results in similar taphonomic pathways.

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The large use of perfluorinated compounds (PFCs) to produce fluoropolymers in consumer and industrial applications, including insecticides, plastics, non-stick surfaces and fire fighting foams has led to a well known widespread occurrence and high concentrations are found in wild life including avian species. For instance, concentrations of perfluorooctane sulfonate (PFOS) in eggs from the common guillemot in the Baltic Sea are among the highest in the Nordic environment. In our laboratory studies, PFOS has caused early mortality in chicken at doses close to concentrations found in eggs of the Baltic guillemot. The mechanisms behind the avian toxicity are unclear but many studies suggest mechanisms including lipid homeostasis. We have designed a method in which hepatic embryonic tissue from chicken (Gallus domesticus) is used to investigate the effects of PFCs on the β-oxidation of fatty acids.  The purpose of this project was to assess the effects of PFOS, perfluorooctanoic acid (PFOA) or perfluorobutane sulfonate (PFBS) on the hepatic fatty acid oxidation using an egg injection technique followed by the use of a tritium release assay with palmitate (16:0) as substrate. The embryos were exposed in ovo and on day 10 of incubation embryo livers are incubated in vitro with tritiated fatty acids. The β-oxidation was significantly induced after exposed to 1 mg/kg PFOS (p = 0.003) and 10 mg/kg PFOS (p = 0.04), and difference in oxidation values was 39% and 34% respectively compared to control. The oxidation effect was not significant (p > 0.05) in samples exposed to PFOA (4 mg/kg) or PFBS (20 mg/kg), however noted, the difference in oxidation values was 18% and 30.5% respectively, compared to control calculated on current average. The results show that in ovo exposure in combination with an in vitro method, using a tritium release assay to detect effects on the β-oxidation of fatty acids in avian embryo hepatic tissue could be a useful method to elucidate possible mechanisms behind avian developmental toxicity.

Master of Science / Department of Horticulture, Forestry, and Recreation Resources / David A. Haukos / There is a wide variety of diseases that affect wild migratory birds. Occurrence, causes, and impacts of disease outbreaks in wild bird populations are rarely studied beyond documentation of large epizootic events. The relationships between the wildlife-livestock-human interface is rapidly blurring together. Global interests in avian diseases increased around 1990 as a result of the prevalence of zoonosis and potential threat to domestic livestock. A central disease reporting protocol does not exist in many states, which has led to a lack of available historical knowledge of disease occurrence that could be used to predict and manage future outbreaks. Due to changes of abundance and distribution of the migrant populations of Ross’s goose (Chen rossii) and Snow goose (C. caerulescens), geese are increasing their stopover duration in Kansas potentially increasing risk of disease outbreaks. We compiled historic records of wild waterfowl disease events in Kansas from 1967-2014 and related the frequency of events with indices of light geese abundance from 1970-2014. We found 32 reports spanning 16 counties consisting of the diseases avian cholera, avian botulism, aspergillosis, renal coccidiosis, west Nile, aflatoxicosis, and mycotoxicosis. Using a retrospective survey, we found there was a significant relationship between population densities of light geese in Kansas during the Mid-Winter Waterfowl Inventory and occurrence of avian cholera. Efforts to increase the understanding of relationships between disease outbreaks and host species will improve management of future disease outbreaks. Understanding factors known to facilitate wild waterfowl disease events (e.g., environmental, species, and individual), may assist in disease identification and determine a disease management course of action. This course of action is predetermined in a disease management plan. Disease management plans should be developed at the state and station level; incorporating planning, response, disease control, and surveillance and monitoring schemes to build upon the centralized disease database and to promote future disease understanding.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20047号 / 理博第4232号 / 新制||理||1608(附属図書館) / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)准教授 生方 貴男, 教授 酒井 治孝, 教授 平島 崇男 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

published_or_final_version / Pathology / Master / Master of Medical Sciences

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