Here I examine five non-migratory sympatric bat species that are similar in their morphology and general ecology: Eptesicus fuscus, three myotid bats, Myotis leibii, M. lucifugus, Myotis septentrionalis, and Pipistrellus (= Perimyotis) subflavus. By examining echolocation call structure, wing and jaw morphology and diet, I defined finer niche differences between species. M. lucifugus and M. septentrionalis differ in the relative abundance of moths in their diet. My results on skull morphology suggest M. lucifugus consumes harder insects than M. septentrionalis. Conversely, my data suggests M. leibii is not as efficient within a cluttered habitat but is capable of foraging in edge habitats. Eptesicus fuscus is capable of efficiently consuming larger insects whereas P. subflavus has echolocation and jaw characteristics that indicate specialization in smaller insects. Significant differences amongst these 5 species are evident based on my data of overall morphology and diet.

Here I examine five non-migratory sympatric bat species that are similar in their morphology and general ecology: Eptesicus fuscus, three myotid bats, Myotis leibii, M. lucifugus, Myotis septentrionalis, and Pipistrellus (= Perimyotis) subflavus. By examining echolocation call structure, wing and jaw morphology and diet, I defined finer niche differences between species. M. lucifugus and M. septentrionalis differ in the relative abundance of moths in their diet. My results on skull morphology suggest M. lucifugus consumes harder insects than M. septentrionalis. Conversely, my data suggests M. leibii is not as efficient within a cluttered habitat but is capable of foraging in edge habitats. Eptesicus fuscus is capable of efficiently consuming larger insects whereas P. subflavus has echolocation and jaw characteristics that indicate specialization in smaller insects. Significant differences amongst these 5 species are evident based on my data of overall morphology and diet.

I studied the social organization and foraging ecology of eastern coyotes (<i>Canis latrans</i>) in Nova Scotia, from 1992 to 1997. Breeding pairs formed the nucleus of coyote social groups and generally traveled with 1-3 other coyotes during winter. Mean winter traveling group size was similar for packs utilizing white-tailed deer (<i>Odocoileus virginianus</i>) or snowshoe hare (<i>Lepus americanus</i>) as a primary food item. Thus, increased use of large prey was insufficient to explain group formation and cohesion of coyotes. Home-range sizes decreased significantly with deer and hare densities. Coyotes used the same territories during winter and summer, and from year to year. During winter, coyotes used, and killed deer, in areas of low deer density proportionately more than expected, likely owing to the increased vulnerability of deer in these areas. Territoriality prevented coyotes from concentrating in deer wintering areas. Based on the analysis of 2,443 scats, deer and hare were the dominant food items. During winter, coyotes killed 76-86% of the deer they consumed. Most deer killed by coyotes were not malnourished. Deer killing rates were negatively correlated with hare density. Mean urinary urea nitrogen: creatinine ratios were correlated positively with hare density. Overall, high use of deer appeared to have been associated with increased vulnerability due to winter severity or, in the case of young fawns, inability to escape. During mild winters, coyotes are forced to focus their hunting efforts on prey other than deer, regardless of density, due to low vulnerability of deer. When severe winter conditions occur, coyotes switch to feeding mainly on deer. Coyotes exhibited a Type I numerical response to the total biomass of deer and hares. Survival of fawns during summer was positively correlated with hare density. However, the total response of coyotes to changes in deer and hare density indicated that the presence of hare increased predation on deer by supporting higher coyote densities. A model based on the total response of coyotes to changes in deer and hare abundance predicted that food competition rather than predation probably regulated deer populations. Extirpation due to intense predation was a possible outcome for deer at densities <0.6 deer/km2.

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<p>Increased pressure has been placed on researchers to focus on processes at an ecosystem level. However, ecological processes operate at multiple scales from an individual predator up to ocean basin migrations, and research across these scales is extremely difficult. More accurate and detailed understanding of prey distributions relative to physical and biological features can greatly aid in understanding top predator distributions and ultimately ecosystem functioning. High resolution acoustic data is a critical tool that can be used to investigate food web linkages at many spatial scales. At a broad scale, migratory top predators are often modeled relative to oceanographic structure as a proxy for the distribution of their prey. At a fine scale, combining novel technologies including fisheries acoustics, real time oceanographic sensors, and digital tags allows examination of decisions made by an individual foraging whale. In the Gulf of Mexico, fish distributions at fine scales (both horizontal and vertical) were examined relative to hypoxic bottom waters to understand potential ecosystem effects. Forage fish distribution (sand lance, Ammodytes spp.) were measured relative to physical features and oceanographic processes up to the decision making of a top predator, the humpback whale (Megaptera novaeangliae). The effect of geostrophic currents and environmental regimes on the deep scattering layers of the central tropical pacific were examined relative to sightings of marine mammals in the area. Analyses across trophic levels and at multiple scales is an important step towards understanding community ecology and ecosystem processes in pelagic systems.</p> / Dissertation

The green turtle, Chelonia mydas, is a circumglobal species that exhibits several important developmental or ontogenetic shifts throughout its life history. The first major shift occurs when juvenile turtles migrate from pelagic habitat, where they forage as omnivores, to coastal neritic habitat, where they become primarily herbivores, foraging on algae and seagrass. Anecdotal evidence and gut-content analyses suggest that juvenile green turtles in south Texas bays, such as the lower Laguna Madre and Aransas Bay, undergo an additional ontogenetic shift during this important life history stage. Evidence from stable isotope analysis (SIA) of scute tissues of green turtles from Texas' lower Laguna Madre and Aransas Bay supports an intermediate stage between this species' shift from pelagic waters to seagrass beds in neritic waters; this additional shift comprises an initial recruitment of post-pelagic juveniles to jetty habitat located on the channel passes Gulf-ward of adjacent bays before subsequently recruiting to seagrass beds in these bays. Examination of stable carbon ([delta]¹³C) and nitrogen ([delta]¹⁵N) isotopes in microlayers of scute tissue from several size classes of green turtles from the lower Laguna Madre and Aransas Bay was used to confirm the occurrence of two ontogenetic shifts. Smaller green turtles (< 35 cm SCL) exhibited more depleted [delta]¹³C signatures and more enriched [delta]¹⁵N signatures, consistent with jetty habitat, compared to those of larger counterparts (> 45 cm SCL) that displayed enriched [delta]¹³C signatures and depleted ¹⁵N signatures, consistent with seagrass habitat. Changes in the isotopic composition between these size classes indicate distinct shifts in diet. Post-pelagic juveniles first recruit to jetty habitat and forage primarily on algae, before subsequently shifting to seagrass beds and foraging primarily on seagrass. These findings indicate the use of a characteristic sequence of distinct habitats by multiple life history stages of green turtles in Texas bays, a conclusion with broad management implications for this endangered species.

AN ABSTRACT OF THE THESIS OF Benjamin S. Lewis Jr., for the Master of Science degree in ZOOLOGY, presented on December, 2, 2015 at Southern Illinois University Carbondale. TITLE: DETERMINING FOOD RESOURCES FOR AMERICAN BLACK DUCKS WINTERING AND SPRING STAGING ON THE EASTERN SHORE OF VIRGINIA MAJOR PROFESSOR: Dr. Michael W. Eichholz I evaluated food availability and food preference for American black ducks (Anas rubripes) wintering and spring staging on the Eastern Shore of Virginia during 2006–2007 and 2007–2008. I estimated food availability by taking core and sweep net sample at 78 sites selected by a stratified random sample throughout our study area, representing 4 dominant wetland habitat types. Seed and invertebrate biomass found in each of these samples were converted to measurements of kilograms per hectare. I found that salt marsh and mudflat habitats contained the highest amount of invertebrate biomass, while freshwater habitats contained the highest amount of seed biomass. I estimated food preference by collecting crop samples from 76 foraging black ducks. Animal matter made up 73% of the aggregate percent biomass of all foods eaten by black ducks. Foods found in black duck crops were compared to their availability in the environment and classified as either selected for, avoided or consumed relative to their availability. Although they were not found to be the most abundant foods, amphipods (Gammarus spp), salt marsh snails (Melampus bidentatus) and ribbed mussels (Geukensia demissa) were foods selected for in black duck wintering habitats. These food items are found most predominantly in salt marsh and mudflat habitats. As may be expected these areas are identified as the most important habitats for black ducks wintering on the Eastern Shore of Virginia. Results from this study provide energetic supply data for bioenergetically based habitat conservation for black ducks in Virginia and in the Atlantic Flyway. I found that the density of food items available for wintering black ducks were lower than densities found in in the more northern wintering range of the black duck and considerably lower than estimates from the wintering regions of other species of dabbling ducks. By concurrently measuring food selection and availability I was also able to reliably determine food preference. Removing avoided food items from food availability estimates provides more accurate estimates of preferred food biomass and it is important for bioenergetically based habitat models to use estimates of preferred food biomass in determining habitat objectives. I found that when avoided food items are removed, estimates of available food biomass decrease substantially, (up to 97%) further emphasizing discrepancies in estimates of food availability between coastal black duck wintering areas and estimates from the wintering regions of other species of dabbling ducks.

La vision est certainement le sens le plus développé chez les rapaces, souvent cités comme les vertébrés possédant la plus grande acuité visuelle. Pourtant, les rapaces figurent parmi les victimes les plus fréquentes des collisions avec des éoliennes et autres dispositifs anthropiques. Etant donné les enjeux de conservation et le coût des opérations de conservation, il est indispensable de mieux comprendre comment les capacités sensorielles des rapaces affectent leur technique de recherche alimentaire et les interactions avec les dispositifs anthropiques (par exemple jusqu’à quelle altitude/distance les vautours peuvent-ils être détecter les charniers et les obstacles potentiels et comment optimiser les mesures de gestion des habitats ?). En ce qui concerne l'olfaction, le postulat ancien que les oiseaux en général ont une olfaction quasi nulle est réfuté grâce à la publication récente d’expériences qui montrent le contraire chez plusieurs espèces d’oiseaux, des passereaux aux oiseaux marins. L’olfaction est-elle vraiment un sens « manquant » chez les rapaces? Pourquoi seuls les vautours américains auraient-ils développé un sens aigu de l’olfaction ? Notre projet d’étude de l’écologie sensorielle des rapaces repose principalement sur de test de conditionnement avec renforcement, conduits sur des oiseaux issus de plusieurs parcs zoologiques de France. L’originalité de notre projet serait de combiner des expériences de vision et d’olfaction, sur une grande diversité d’espèces (Vautours, Buses, Milans), d’origine phylogénétique, de régimes alimentaires et de technique de recherche alimentaire différents, à la fois au sol et en vol. La première étape aura lieu en conditions contrôlées en volières, avec des expériences de conditionnement opérant après dressage : réponses des oiseaux à différents stimuli visuels et odeur. Dans un deuxième temps des expériences en vol pourront être menées, sur des oiseaux dressés à effectuer des vols libres, dont les mouvements précis peuvent être suivis en 3 dimensions par des balises GPS couplées à des accéléromètres et des caméras vidéos. Il serait alors possible de connaître précisément les capacités sensorielles utilisées pour la recherche alimentaires de chaque espèce et d’analyser les comportements de vol en lien avec l'aérologie. / The vision is certainly the most developed sense in raptors, and these birds are cosidered as the vertebrates with the greatest visual acuity. However, raptors are among the most frequent victims of collisions with wind turbines and other human features. Given the conservation issues and the cost of conservation operations , it is essential to understand how sensory abilities of raptor affect their foraging ecology and interactions with human features (eg at which altitude / distance vultures can detected graves and potential obstacles and how optimize the measure of habitats management). But vision is not the only sense that raptor may have. Olfaction in birds was historically neglected, but recent evidence suggests that many bird species, from passerines to seabirds, use olfaction. Consequently, it make sense that olfaction may lead some behaviours in raptor too. To date however olfaction has been searched and shown only in the American vultures. Our project aims to study the sensory ecology of raptors based primarily on captive animals and condition protocols. The originality of our project is to combine the experience of vision and olfaction, on a wide variety of raptor species present in French zoos, with different phylogenetic origin, diets, and different foraging ecologies. The first step will takes place under controlled aviaries conditions, with operant conditioning experiments: responses of birds to different visual and odor stimuli. In a second phase, flight experiments will be conducted on birds trained to perform free flights, whose precise movements can be tracked in three dimensions by GPS tags coupled with accelerometers and cameras videos. It would then be possible to determine precisely the sensory capabilities used for food research for each species, and analyze the flight behaviour with respect to aerology

Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol) / It is widely reported that snakes can be major predators of avian nests, but the use of a single avian prey type by competing species has rarely been examined. This study aimed to investigate predation of a single food resource by the sympatric snakes Naja nivea and Dispholidus typus. Specifically, I aimed to 1) identify factors influencing snake presence in sociable weaver colonies and 2) quantify snake predation and potential differences in the consumption of prey by the two competing snakes. I used repeated visual surveys of sociable weavers to obtain presence-absence data of cape cobra and boomslang in sociable weaver colonies over an entire breeding season. I related the presence-absence data of the two snake species to spatially- and temporally-variable factors using principal component analyses (PCA) and multiple logistic regression analyses. The presence of snakes in sociable weaver colonies is primarily influenced by temporal factors, but spatial factors also play a role.

Moist-soil wetlands that are seasonally flooded provide important habitats for waterfowl in the Mississippi Alluvial Valley (MAV). These wetlands often contain tall and dense vegetation that may constrain waterfowl use before natural openings form. During winters 2006–2009, I estimated abundances of waterbirds, seeds and tubers, and invertebrates in response to autumn, prelooding treatments of light disking, mowing, and no manipulation (control) of vegetation in 26 moist-soil wetlands in the MAV. Seeds and tubers were most abundant in control and mowed plots in late autumn. Decomposition was least and invertebrate abundance was greatest in control plots during winter. Dabbling ducks were most abundant in mowed and disked plots during winter. Lightly disked plots contained ~30% fewer seeds and tubers than mowed and control plots. In late winter, ~260 kg[dry]/ha of seeds and tubers remained among mowed, disked, and control plots. Therefore, autumn mowing of robust moist-soil vegetation can be used to create an interspersion of emergent vegetation and open water attractive to waterfowl and conserve waterfowl foods. Additionally, I identified 6 seed taxa that may not be used for food by dabbling ducks (i.e., Amaranthus spp., Cyperus odoratus, Eleocharis spp., Ipomoea spp., Jacquemontia tamnifolia, Sesbania herbacea) and estimated that removing these and other taxa not reported in diet literature in the MAV resulted in a ~31% reduction in estimated moist-soil food availability for ducks. In other experiments, I estimated that waterfowl reduced experimentally placed Japanese millet (Echinochloa frumentacea) to ~10 kg/ha and other natural seeds and tubers to ~170 kg/ha in experimental plots in mid-winter. However, waterfowl did not abandon wetlands or stop foraging when seed reduction ceased, suggesting residual abundances of seeds and tubers represented a food availability threshold (FAT). Using the median FAT value of 220 kg/ha from both experiments and removing 31% of seed mass that may not be consumed by dabbling ducks, results in a ~70% decrease in moist-soil seed availability in the MAV. Conservation planners should consider reducing the current estimates of seed and tuber availability and recommend increasing active management or implementation of additional managed, moist-soil wetlands in the MAV.