Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
Browse
8 results
Search Results
Item Description and ontogenetic assessment of a new Jehol microraptorine(Montana State University - Bozeman, College of Letters & Science, 2014) Poust, Ashley William; Chairperson, Graduate Committee: David VarricchioFossils from the Jehol Group (Early Cretaceous, Liaoning Province, China) have greatly contributed to our understanding of the morphology and diversity of Paraves, the group of dinosaurs including sickle-clawed dromaeosaurs, large-brained troodontids, and avialians, the ancestors of modern birds. However, many taxa are represented by only a few specimens of unclear ontogenetic age. Without a thorough understanding of ontogeny, the evolutionary relationships and significance of character states may be obscured within paravian dinosaurs. A complete specimen of a new taxon of microraptorine dromaeosaur, Wulong bohaiensis gen. et sp. nov., from the Jiufotang Formation (upper Jehol Group) exhibits clearly juvenile morphology. The dinosaur is small and preserved in articulation on a single slab. It has microraptorine features such as a subarctometatarsalian foot, a short first manual digit, and a prominent tubercle on the pubis. Phylogenetic analysis substantiates this assignment. It also possesses more than 29 tail vertebrae, inclined pneumatic foramina on its dorsal vertebrae, and an unusually large coracoid fenestra, which with other features argue that it is a new taxon. This individual shows many osteological markers of immaturity identified in other archosaurs. Skull elements, all visible neurocentral sutures, pubes, and proximal tarsals remain unfused. Grainy surface texture of the cortical bone and poor ossification of long bone articular surfaces further supports an immature status. Histologic samples of the tibia, fibula, and humerus of this individual (the first microraptorine theropod to be sampled) confirm that it was around a single year in age and still growing at death, but that the growth had slowed. This slow down in growth is interesting in light of the presence of pennaceous feathers extending from the fore- and hind-limbs and, notably, two long plumes extending more than 12 cm from the tip of the caudal series. This indicates that presence of a variety of feather types, including filamentous feathers, pennaceous primaries, and long rectrices, likely used for ornamentation, preceded skeletal maturity and full adult size.Item History, nesting biology, and predation ecology of raptors in the Missouri Coteau of northwestern North Dakota(Montana State University - Bozeman, College of Letters & Science, 1993) Murphy, Robert KevinItem Ecology of the bald eagle and osprey in Yellowstone National Park,(Montana State University - Bozeman, College of Letters & Science, 1975) Swenson, Jon E.Item Bald eagles of the San Luis Valley, Colorado : their winter ecology and spring migration(Montana State University - Bozeman, College of Letters & Science, 1984) Harmata, Alan R.Item Investigation of bird induced outages on Montana Power Company's 500 kV transmission lines(Montana State University - Bozeman, College of Engineering, 1996) Maehl, David RobertItem Pellet and scat analysis as indicators of past and present habitats(Montana State University - Bozeman, College of Letters & Science, 2000) Craighead, April Charmaine H.Item Predation on meadow voles : predator response to vole abundance and vole response to predator exclusion in Red Rock Lakes National Wildlife Refuge, Montana(Montana State University - Bozeman, Graduate School, 2011) Burgener, Joel Ryan; Chairperson, Graduate Committee: Peggy Taylor.Small mammals such as meadow voles exhibit complex and puzzling multi-annual population cycles. Predators can have an effect on these cycles though the precise relationship is not completely understood. I undertook this study to 1) quantify the response of predators to small mammal abundance and 2) determine the relative roles of mammalian meso-predators and raptors on abundance and survivorship of small mammals in wet meadow habitat at Red Rock Lakes National Wildlife Refuge, southwest Montana. as well as the response by predators to different levels of small mammal abundance. Two randomly placed trapping grids were placed inside three adjacent grazing units. Two additional treatment trapping grids were placed inside one of the grazing units with an electrified polywire fence to exclude mesopredators. The trapping occurred in July and August of 2010 on the Refuge. The trapping occurred in three primary sessions with four individual trapping days (secondary sessions) per primary session in each grazing unit. Predators were monitored by conducting visual raptor surveys and camera trapping. My results indicated that partial predator exclusion did not improve vole survivorship in fact some raptors used the fence posts as supplemental perches, as some bore signs of use. My results also did not support the hypothesis that raptor abundance tracked vole abundance. However, vole abundance was significantly higher during 2010 than in previous years. The increase in vole abundance resulted in other factors driving habitat selection by raptors. The camera traps did not provide any information about the use of the wet meadow by mammalian predators, however other signs of mammalian predators were observed in the trapping area during the study. Further study may shed more light on the use of supplemental perches by raptors and how mammalian predators are using the wet meadow habitat on the Refuge.Item Rough-legged hawk winter ecology in Southeastern Idaho(Montana State University - Bozeman, College of Letters & Science, 1984) Watson, James Ward; Chairperson, Graduate Committee: Robert L. EngEcology of the American rough-legged hawk (Buteo lagopus) was investigated during winters 1981-82 and 1982-83. Research was conducted in sagebrush-dominated habitat on the Idaho National Engineering Laboratory Site in southeastern Idaho. Spatial distribution of the hawk population was influenced by vegetation canopy, which reduced foraging efficiencies of monitored hawks. Temporal distribution was influenced by rabbit carrion availability and snow cover over 10 em, which accounted for 65% of the variability in hawk numbers. Hawks consumed carrion and voles in different proportions on sagebrush habitat and adjacent farmland. Radio-tagged hawks exhibited two patterns of range use. Three hawks maintained a pattern of drift between small, non-overlapping ranges. Four hawks occupied well-defined ranges between 70.2 and 541.2 km ² which encompassed smaller, overlapping weekly ranges. Weekly ranges were characterized by size reduction in mid-winter due to increased perching activities which conserved energy. Monitored hawks also shifted to grass-dominated areas or highways in the period of severe weather. Transmission lines were important components of ranges. Utility poles influenced range shape and size and were used extensively as hunting and roosting. substrates. Hawks exhibited little range defense but defended perches and prey near activity centers. Other aspects of social behavior, hunting success, roosting behavior and food habits were reported. Premigratory movements up to 120 km from ranges were exhibited by three hawks. Movements of two hawks averaged 120 km per day for two days of migration. Winter range fidelity was displayed by at least one individual. The presence of marked hawks resighted in states surrounding Idaho reflected the opportunistic nature of this species. Theoretical considerations suggested this population originates in western Canada.