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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Research in motion: patterns of large-scale migration in dragonflies and birds / Patterns of large-scale migration in dragonflies and birds

Matthews, John Holley, 1968- 29 August 2008 (has links)
The work I present here can be broadly described as focusing on the spatial, temporal, and ecological basis to patterns of movement by highly vagile organisms. From this perspective, the differences between chapters are matters of scale: community versus population ecology, and movement by thousands of birds through two localities versus a study of a single invertebrate species crossing North America. Animal movement over large scales has proven difficult to study throughout the history of biology. Proximal challenges have largely reflected practical problems with observing spatial displacement in individual organisms. Population-level evolutionary and ecological analyses -- ultimate explanations for movement -- depend on solutions to those proximal challenges. Here, I have tried to interweave both proximal and ultimate approaches. Large-scale movement also presents challenges from a conservation perspective. The conservation implications of the final chapter are immediately applicable to avian researchers and resource managers. In contrast, understanding why and how Anax junius Drury (Odonata: Aeshnidae) is moving across North America does not have such direct conservation implications. The species is not endangered, nor have threats to its range or behavior been suggested. My interest instead grew from the need for a model system to explore aquatic invertebrate conservation as well as the practical difficulties of studying long-distance migrants of all kinds, invertebrate and vertebrate. These chapters thus form a whole through their focus on determining how and why organisms move over large spatial scales and the connection of that behavior to habitat. Many species move great distances during individual lifetimes. Threats from land-use change, habitat fragmentation, and climate shifts will all have -- are already having -- impacts on many species. We need accurate, inexpensive, and effective tools to be able to count, compare, detect, define, delineate, and explain patterns of movement. I have endeavored to improve a few of these tools and, if possible, provide a few new examples and explanations grounding that movement.
2

Weather and stray migrants - a model and case study

Félin, Béatrice January 1974 (has links)
No description available.
3

The Influence of Energetic Condition on Flight Initiation and Orientation of Migratory Passerines in the Gulf of Maine Region

Covino, Kristen M. January 2008 (has links) (PDF)
No description available.
4

Reproductive insularity in a migratory sparrow: A field study of Lincoln's sparrow populations in Southern California

Greyhaven, Cin 01 January 1991 (has links)
Melospiza lincolnii -- San Bernardino and San Jacinto mountain ranges -- migrational return -- Dispersal - Morphometric analysis.
5

Weather and stray migrants - a model and case study

Félin, Béatrice January 1974 (has links)
No description available.
6

The global ecology of bird migration : patterns and processes

Somveille, Marius January 2015 (has links)
No description available.
7

Migratory behavior of the elf owl (Micrathene whitneyi)

Tellez, Carol Ann Mead, 1940- January 1968 (has links)
No description available.
8

Some aspects of bird migration in northeast England

Evans, P. R. January 1966 (has links)
No description available.
9

The wintering and migration ecology of the whinchat Saxicola rubetra, a declining Palearctic migrant

Blackburn, Emma January 2014 (has links)
For migrant birds, the non-breeding season can greatly influence survival and future reproductive success. Knowledge of annual and overwinter survival, the degree of site fidelity and habitat use in the non-breeding season, migration ecology, routes and stopovers, and whether these differ with age or sex is fundamental to understanding population dynamics, vulnerability to anthropogenic habitat degradation, and consequently for understanding the severe widespread declines of migrant bird species. The degree to which a migrant is a winter specialist or generalist is likely to be central to understanding population dynamics. I studied survival rates and the wintering and migration ecology of a declining Palearctic migrant, the whinchat Saxicola rubetra, wintering in West Africa, to establish how the non-breeding season may influence migrant population dynamics. Whinchats were extremely site faithful to both within and between years, holding distinct winter territories and returning to those territories in subsequent winters, despite the opportunity to relocate. Overwinter survival was very high and annual survival was comparable to or higher than that reported on the breeding grounds. Because our power to detect resident and dispersing birds was high, survival rates likely estimated true survival well. Habitat characteristics varied widely across territories and territories were smaller if more perching shrubs and maize were present. Most individuals showed a tolerance or even preference for human modified habitats. Some individuals may have multiple wintering sites. There was no evidence of dominance-based habitat occupancy or any differences in winter ecology, site fidelity, survival and most aspects of migratory behaviour between age and sex classes. Migratory connectivity occurred only on a large-scale and individual migratory behaviour was also varied. Fundamentally, the results suggest a generalist strategy in the non-breeding season within their wintering habitat of open savannah, most likely as an adaption to stochastic site selection within the wintering range for juveniles undertaking their first migration plus changing and unpredictable conditions both within and between years. Consequently, wintering conditions may not significantly limit whinchat populations and mortality is probably highest during active migration. Notably, non-specialist migrants such as whinchats may have some resilience at the population-level to the increasing anthropogenic habitat modification occurring in Africa, suggesting that conditions during migration and in Europe may be driving declines; yet establishing the currently unknown thresholds of any resilience is likely to be fundamental for the future conservation migrants.
10

Vybrané aspekty podzimního tahu ptáků a netopýrů přes horské sedlo / Selected aspects of autumn migration of birds and bats over a mountain pass

Koukolíková, Anna January 2017 (has links)
Mountain passes situated in mountains of east-western orientation serve as important bird and bat migration corridors. Due to the increased concentration of migranting individuals in both groups, mountain passes can be used to study various aspects of migratory ecology. Within the Czech Republic, the most important site of this type is Červenohorské sedlo in Jeseníky. In this thesis, selected aspects of autumn migration (composition of the migratory population, phenology, factors influencing its intensity) of birds and bats during the autumn season were compared. In addition, data usability was compared for a reliable determination of autumn phenology in selected model bird species based. The comparison was between standardized mist netting in the mountains and set of data obtained from faunistic observations throughout the Czech Republic. Data from mountain mist netting has proven to be a more reliable indicator of the timing of bird migration, mainly because most species fly directly and quickly over the mountains, while in low-level observations there is a risk of mixinglocal and migratory populations. Also the number of observed individuals in some cases reflects the interest in extreme late occurrences in many species, which are generally given more attention and are more frequently recorded...

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