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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.
21

Habitat use by the golden-cheeked warbler in Texas

Newnam, John Calvin 15 May 2009 (has links)
Understanding species-habitat relationships is fundamental to the conservation of a species. This is especially important when the species is considered endangered. The Golden-cheeked Warbler is a habitat specialist that breeds only in oak-juniper woodlands (considered a climax forest) of central Texas. The warbler was listed as endangered under the federal Endangered Species Act primarily because of habitat loss and fragmentation. Conservation measures include the preservation of existing habitat and attempts to manage and enhance areas that once supported the warbler to return to the climax oak-juniper woodlands. My objectives were (1) to quantify the vegetation structure and species composition by vegetation volume of occupied warbler habitat across the breeding range in Texas and (2) to quantify the habitat use by the warbler in categories of behavior, substrate, height, and tree species. Instantaneous, focal animal behavioral observations were collected for three breeding seasons at six sites across the range of the warbler. Warbler behavior and microhabitat use were compared to availability of vegetation volume by height class and tree species. I found that Goldencheeked Warbler habitat varied by vegetation volume, canopy height and tree species among all sites. The warbler preferred twigs and foliage and the upper two height classes of the habitat structure for all behaviors. Tree species use did not match availability at any sites. The one consistent species result was the warbler used Ashe juniper significantly less than it occurred at all sites. Other major species were used disproportionately to the species occurrence at each site. Some tree species were used more often than they occur in the habitat while others species were used less than they occur in the habitat. Preferences for height class and tree species use were not significantly influenced by vegetation volume. Some other factor not measured such as prey availability may be the cause. Because warbler habitat characteristics and use vary across the range, any efforts to manipulate vegetation to become habitat must consider regional characteristics of Golden-cheeked warbler habitat.
22

Male parental care and extrapair copulation effort in hooded warblers (Wilsonia citrina)

Pitcher, Trevor Edgar. January 1998 (has links)
Thesis (M. Sc.)--York University, 1998. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 31-40). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL:http://wwwlib.umi.com/cr/yorku/fullcit?pMQ27371.
23

CHANGES IN PATTERNS OF TERRITORY AND HABITAT OVERLAP IN WOOD-WARBLERS OVER EVOLUTIONARY TIME

Conboy, Mark 09 January 2012 (has links)
Patterns of community assembly among organisms are highly influenced by the ecological traits and strategies of the species that make up those communities. The conservation of ancestral traits can be important in determining how closely related species partition space and habitat on a local scale. Shared ecological traits and strategies of closely related species suggest that they should overlap in space and use similar habitats. However, ecological similarity may result in fitness costs when closely related species live together. Previous work on birds suggests that close relatives avoid each other by using different habitats. I used the radiation of Dendroica wood-warblers to test these two alternative hypotheses and determine how closely related species partition space and habitat, and how patterns of spatial overlap and habitat use change over evolutionary timescales. I measured territory and habitat overlap among nine sympatric species of Dendroica, Setophaga and Mniotila to determine how time since common ancestry is related to patterns of spatial overlap and habitat use at the Queen's University Biological Station in eastern Ontario. I predicted that closely related species would separate by habitat and not overlap their territories. However, I found that the two most recently diverged species pairs overlap their territories and habitats significantly more than do pairs of more distantly divergent species. This pattern contrasts with previous studies on wood-warblers and the ecologically similar Phylloscopus leaf-warblers. These results suggest that during allopatric speciation Dendroica species do not differentiate in habitat on a local scale; rather, habitat differentiation occurs after closely related species have returned to sympatry. / Thesis (Master, Biology) -- Queen's University, 2012-01-09 11:32:42.032
24

Predictive modeling techniques with application to the Cerulean warbler (Dendroica cerulea) in the Appalachian Mountains Bird Conservation Region

Shumar, Matthew Buhrl. January 2009 (has links)
Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains x, 98 p. : ill. (some col.), col. maps. Includes abstract. Includes bibliographical references. WVU users: Also available in print for a fee.
25

Habitat use, demography, and population viability of disturbance-dependent shrubland birds in the Missouri Ozarks

Fink, Alix D. Dowling, January 2003 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.
26

Habitat use, demography, and population viability of disturbance-dependent shrubland birds in the Missouri Ozarks /

Fink, Alix D. Dowling, January 2003 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.
27

Relative abundance and habitat selection by Cerulean warblers in southern Indiana

Basile, Cynthia January 2002 (has links)
There is no abstract available for this thesis. / Department of Biology
28

Breeding biology and habitat associations of cerulean warblers in southern Indiana

Register, Sarah M. January 2007 (has links)
The Cerulean Warbler (Dendroica cerulea), a once common summer inhabitant and breeder in southern Indiana, has declined at both local and continental population levels. Effects of specific silvicultural practices on the distribution and abundance of the Cerulean Warbler is unknown. During the summers of 2005 & 2006, Cerulean Warblers were surveyed within the Morgan-Monroe and Yellowwood state forests, as well as the Hoosier National Forest in southern Indiana. Three forest types were surveyed; unharvested reference sites were compared with single tree selection treatments and treatments where a combination of group and single tree selection was used. Mean bird abundance was estimated from bird surveys to determine if a correlation exists between silvicultural regimes and Cerulean Warbler abundance. Cerulean Warblers were located in all treatment types, with no significant differences in abundance between or among treatment types examined. These results suggest that uneven-age management practices, such as single tree and group selection harvesting, provide suitable breeding habitat for Cerulean Warblers.Knowledge of Cerulean Warbler (Dendroica cerulea) male pairing status based on song rates and frequencies, as well as familiarity with non-song vocalizations could be an effective management tool when studying this species. Cerulean Warblers were recorded throughout the breeding season, and 18 song variables were measured and compared between paired and unpaired males using Logistic Regression. Unpaired males had higher song rates and higher minimum frequencies than paired male counterparts. Female and fledgling call notes were also recorded and quantitatively analyzed. These analyses offer further understanding of intraspecific call functions of this species. / Department of Biology
29

Foraging ecology of male Cerulean warblers and other neotropical migrants

George, Gregory A., January 2009 (has links)
Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains ix, 85 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references.
30

Mezidruhová hybridizace u rákosníků rodu Acrocephalus / Interspecific hybridization in Acrocephalus warblers.

Majerová, Veronika January 2012 (has links)
Acrocephalus warblers have gone through the adaptive radiation during last severalmillion years, which gave rise to thirty one species occupying mainly Eurasia,Africa and Australia. The majority of species are morphologically very similar,however, they differ in ecological requirements, migration strategy, and song.Interspecific hybridization seems to be quite common among Acrocephaluswarblers, not only between sister species, but also between more distantly relatedtaxa. The main goal of this study was to determine whether this hybridization leadsto gene flow between species and which factors affect the rate of interspecific geneflow. For this purpose we conducted population-genetic analysis in three Europeanspecies of the Acrocephalus warblers of the subgenus Notiocichla: reed warbler (A.scirpaceus), marsh warbler (A. palustris), and blyth's reed warbler (A. dumetorum).Our results based on the analysis of sequence data from eight nuclear loci indicate,that gene flow between the studied species occurs, but only in one direction. Thegene flow is higher between genetically more related species than betweenecologically more similar species. We also estimated that the reed warbler and themarsh warbler diverged approximately 1,1 million years ago. The blyth's warblerand ancestor of the reed and marsh warbler...

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