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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.
211

Reproductive Ecology of Greater Sage-Grouse in Strawberry Valley, Utah

Baxter, Jared Jeffrey 01 December 2016 (has links)
Greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) are a species of conservation concern in the rangelands of western North America due to their dramatic decline over the last half century. Effective conservation and management of sensitive species requires an understanding of how species respond to management actions. We examined two aspects of the reproductive phases of sage-grouse: nest predation, and habitat selection by female sage-grouse with chicks. In Chapter 1, we developed resource selection functions to assess the influence of mechanical treatments of mountain big sagebrush (Artemisia tridentata vaseyana) on habitat selection by greater sage-grouse with chicks. Post-treatment sage-grouse showed stronger selection for treatments and treatment edges than did pre-treatment sage-grouse. This altered pattern of selection by sage-grouse with broods suggests mechanical treatments may be a suitable way to increase use of mountain big sagebrush during the brooding period. In Chapter 2, we assessed the effect of habitat edges on nest predation of sage-grouse. The "edge effect" hypothesis states that habitat edges are associated with reduced nest success for birds. We tested the edge effect hypothesis using 155 nest locations from 114 sage-grouse. We derived edge metrics for 11 habitat cover types to determine which variables may have affected nest predation. We found support for the edge effect hypothesis in that nest predation increased with increasing edge density of paved roads. We provide evidence that the edge effect hypothesis may apply to greater sage-grouse and their habitats. Based on our results, we recommend minimizing disturbances that fragment critical nesting habitat of greater sage-grouse.
212

Perceptions of Empty Nest Mothers From Diverse Socioeconomic Backgrounds With Boomerang Kids

Lary, Banning Kent 01 January 2015 (has links)
In the United States, a growing number of young people are failing to launch into self-sufficiency, a characteristic of adulthood recognized by most cultural groups. These "boomerang children" return home and interrupt the life course development of their "empty nest" mothers who must suspend plans for self-development. How mothers from different socioeconomic backgrounds cope with this countertransitional phenomenon while preparing their children for successful relaunch is not well known. Elder's life course paradigm provided the theoretical framework for this phenomenological study. Perceptions were collected from an ethnically diverse group of 23 empty nest mothers with 30 boomerang children and seven boomerang grandchildren from five U.S. states, recruited using criterion-based convenience sample. Data were collected through recorded telephone interviews that were transcribed verbatim, and analyzed using Saldana's codes-categories-emergent themes model. The findings revealed that boomerang children caused emotional and financial distress, a reassessment of parenting skills, and that boomerang grandchildren reinvigorated the mother's prime identity as a caregiver. These findings were consistent regardless of ethnicity or socioeconomic status. This study contributes to the empirical literature by depicting the boomerang phenomenon as a shift in cultural expectations which represents a new phase in the life course development paradigm. Findings from this study can also guide the work of future researchers, assist mental health counselors who deal with these issues, and inform school guidance counselors who design career trajectories for students.
213

Population Dynamics and Movements of Translocated and Resident Greater Sage-Grouse on Anthro Mountain, Utah

Gruber, Natasha W. 01 December 2012 (has links)
Declining populations of greater sage-grouse (Centrocercus urophasianus; hereafter sage-grouse) have increased stakeholder concerns regarding the management and stability of the species range-wide. Numerous conservation strategies have been identified to restoring sage-grouse population declines to include species translocations. Translocations have been used for many different wildlife species to help sustain genetic heterogeneity, reestablish, and augment declining populations. In a recent translocation study, researchers identified the protocols used to successfully translocate sage-grouse to restore declining populations in Strawberry Valley, Utah. This translocation occurred in a high elevation basin buffered by geomorphic barriers. I evaluated these protocols for use in translocating sage-grouse to augment a declining population that inhabited Anthro Mountain in northwest Utah. Anthro Mountain is a high elevation mountain dominated by sagebrush (Artemisia spp.) void of geomorphic barriers. I compared annual production, survival (i.e., vital rates), habitat use, and movements of translocated birds and their progeny to the resident population. Lastly, I described the integration of translocated birds with resident birds and the overall efficacy of the translocation effort. I radio-collared and monitored 60 translocated female sage-grouse from Parker Mountain, Utah over a 2-year period (2009 and 2010) and compared their vital rates to 19 radio-marked resident sage-grouse. Adult survival was similar for resident and translocated birds, but higher for both groups in 2010 than in 2009. However, overall survival of both resident and translocated birds was lower than range-wide survival estimates. Nest success was slightly higher for resident birds than translocated birds but positively correlated to grass height for both groups. Chick survival was also slightly higher for resident birds than for translocated birds, and higher overall in 2010 than in 2009. Chick survival was positively correlated to grass cover for both groups. Translocated birds used similar habitats and exhibited migration behaviors similar to resident birds. From a methodology perspective, the translocations protocols were successful because the translocated birds quickly acclimated to the release area, and their survival and reproductive success were similar to the resident birds. The effect of the translocation on augmenting the local population was inconclusive.
214

Female choice and paternal care in the fifteen-spined stickleback, Spinachia spinachia

Östlund-Nilsson, Sara January 2000 (has links)
<p>In the fifteen-spined stickleback, <i>Spinachia spinachia</i>, males provide females with direct benefits by fanning, cleaning and guarding the offspring. Males announce their parental skills through intense body shakes during courtship. Females preferred to mate with more intensely shaking males. As a result, females got better fathers for their offspring, as such males achieved a higher hatching success. Not only did male behavioural cues attract females, but males also used their nests as extrabodily ornaments. The nest is held together with shiny secretional threads consisting of a glycoprotein. Females chose to spawn in nests with more secretional threads. A likely reason for this is that the threads are metabolically costly for the male to produce and the amount of secretion indicates a male's nutritional status, which is of great importance as parental duties are energetically costly. Moreover, females preferred nests built high up in the vegetation, as such nests were safer from egg predators. Competition with other males for females favoured males building higher nests than did their neighbours, probably because females preferred high nests. Male-male interactions, such as sneaking and egg stealing, caused decreased paternity among males in nature as assessed by a microsatellite analysis. Males adjusted their paternal effort according to their previous investment in the brood, but not according to paternity. Thus, female choice is based on multiple cues and results in better paternal care. Males invest in courtship, male-male competition, nest construction and paternal care, the outcome determining their success in mate attraction.</p>
215

Breeding biology and habitat associations of the Altamira Oriole and Northern Beardless-Tyrannulet in the Lower Rio Grande Valley, Texas

Werner, Scott Michael 15 November 2004 (has links)
I studied the breeding biology and nesting ecology of the Altamira Oriole (Icterus gularis) and Northern Beardless-Tyrannulet (Camptostoma imberbe), two songbirds inhabiting remnant tracts of Tamaulipan brushland of the Lower Rio Grande Valley, Texas during 2002-2003. I found 76 active oriole nests, 7 of which were reused for second broods, for a total of 83 nesting attempts. I estimated that nearly 20% of the oriole breeding population were subadult, or second-year orioles, which is extremely rare for this species. Oriole breeding pairs were found in high densities and may be at their highest level at the study sites since the 1970s. Fifty-nine percent of oriole nests fledged, and 37% failed. Six nests produced Bronzed Cowbird (Molothrus aeneus) fledglings. Vegetation analysis suggests that orioles prefer the tallest trees at the sites in which to place their nests. A greater number of fallen logs near the nest was also a predictor of nest sites, which suggests that orioles prefer scattered woodlands, but also that many of the forests probably continue to shift to a more open, thorn-scrub climax stage. I monitored 28 Northern Beardless-Tyrannulet nests, which were restricted to a smaller number of study tracts than Altamira Orioles. Historical records are lacking for Northern Beardless-Tyrannulets at these sites, but my surveys indicated that there were similar seasonal numbers of tyrannulets at some of the study sites as there were during 1996-1998. Forty-three percent of nests were successful and 57% failed. Higher abundances of epiphytic Spanish moss (Bromeliaceae: Tillandsia usneoides) and ball moss (Bromeliaceae: Tillandsia recurvata) were the most important predictors of nest sites. The continued existence of these two species in South Texas will depend upon the preservation of tall forests, and in the case of the tyrannulet, forests rich in Tillandsia epiphytes.
216

Female choice and paternal care in the fifteen-spined stickleback, Spinachia spinachia

Östlund-Nilsson, Sara January 2000 (has links)
In the fifteen-spined stickleback, Spinachia spinachia, males provide females with direct benefits by fanning, cleaning and guarding the offspring. Males announce their parental skills through intense body shakes during courtship. Females preferred to mate with more intensely shaking males. As a result, females got better fathers for their offspring, as such males achieved a higher hatching success. Not only did male behavioural cues attract females, but males also used their nests as extrabodily ornaments. The nest is held together with shiny secretional threads consisting of a glycoprotein. Females chose to spawn in nests with more secretional threads. A likely reason for this is that the threads are metabolically costly for the male to produce and the amount of secretion indicates a male's nutritional status, which is of great importance as parental duties are energetically costly. Moreover, females preferred nests built high up in the vegetation, as such nests were safer from egg predators. Competition with other males for females favoured males building higher nests than did their neighbours, probably because females preferred high nests. Male-male interactions, such as sneaking and egg stealing, caused decreased paternity among males in nature as assessed by a microsatellite analysis. Males adjusted their paternal effort according to their previous investment in the brood, but not according to paternity. Thus, female choice is based on multiple cues and results in better paternal care. Males invest in courtship, male-male competition, nest construction and paternal care, the outcome determining their success in mate attraction.
217

Parasite-host interactions in an arctic goose colony

Harriman, Vanessa Brooke 02 January 2007
The arctic is currently experiencing some of the greatest rates of warming. Newly emerging diseases in the arctic are of particular interest due to the implications these may have at southern latitudes if temperatures continue to rise around the globe. It is important to document changes in pathogen populations, such as alterations in range, virulence, prevalence, and abundance, and the effect these may have on their host populations. Parasites influence the reproductive success of their hosts in some cases. Studies on impacts of ectoparasites on avian reproductive success have generally been focused on species with altricial young. I studied the abundance of an apparently newly emerging nest-parasite and the effects of this parasite on Rosss (<i>Chen rossii</i>) and lesser snow goose (<i>Chen caerulescens caerulescens</i>) reproductive success in the Karrak Lake goose colony, Nunavut, Canada from 2001 to 2004. <p>The nest parasite, identified as the flea <i>Ceratophyllus vagabundus vagabundus</i>, was associated with goose eggs covered with spots of blood. The proportion of goose egg-shells covered by blood was positively correlated with flea abundance in the nest. This relationship allowed the use egg blood-coverage as an index of flea abundance for remaining analyses. Flea abundance in goose nests was associated with variables associated with the host and the hosts habitat. I used general linear models in conjunction with Akaikes information criterion (AIC) to determine which factors were most important in influencing flea abundance in goose nests. The most parsimonious model to explain the relationship between egg blood coverage and flea abundance in goose nests included goose clutch size, age of nest bowl (new vs. old), history of nesting by geese on a specific plot within the colony, habitat within 0.5m of nest, and year. The best predictor of flea abundance was the age of the nest bowl, with nest bowls re-used by geese containing more fleas than new bowls. This relationship was expected as fleas over-wintered in goose nests at the Karrak Lake colony.<p> Logistic regression and AIC were used to determine whether egg blood-coverage was an important variable influencing nest success. All top five models included blood-coverage. Goose nest success was negatively influenced by fleas in most years. There was a threshold of egg blood-coverage at which nest success was affected, and this threshold varied, with >20% blood indicating a significant decline in nest success in two years, and >5% blood-coverage indicating a decrease in nest success in one year. To my knowledge, this is the first study that has examined the parasites of avian nests in an arctic ecosystem and was also the first to investigate the effect of nest parasites on birds with precocial young. More research is needed to determine what factors limit this flea population and whether fleas may become a regulating factor for geese in the Karrak Lake colony.
218

Nesting Range, Spatial Use, Habitat Selection and Sex Identification of the Greater Raodrunner (Geococcyx californianus)

Montalvo, Andrea 14 March 2013 (has links)
I conducted this study to better understand the greater roadrunner’s (Geococcyx californianus) spatial use, nest site selection, and sexual morphometrics. Data were first collected from a roadrunner population in Fisher County, Texas. I trapped, measured, and removed feathers for sex confirmation through DNA PCR analysis. I then fit the roadrunners with a radio transmitter and released them at the capture site. I captured a total of 10 birds (1 male and 9 females) and triangulated the location of each bird 2-4 times per week from February to August 2011 during the roadrunner nesting season. The data produced a mean minimum convex polygon nesting range of 43.01-ha, a 50% core utilization distributions of 11.88-ha, and an overlap index of 33.05 percent. Habitat selection ratios showed a preference for ridge as well as grassland habitat and avoidance of bare ground and flatland habitats. The location data from west Texas was further analyzed to build a predictive logistic regression model to understand the significant site characteristics in roadrunner land use during the nesting season. It was determined that percent rock (-0.12, P = 0.0001) and percent litter (-0.05, P = 0.0052) were the best predictors in determining actual from random locations. Rock references open area for hunting, transportation as well as ridge habitat. Litter alludes to region below dense stands of shrubs and is used by roadrunners for evasion from threats and as shade for thermoregulation. The measurements from the roadrunners in west Texas as well as museum specimens from across their natural range were combined to develop an easy, inexpensive, and field-relevant sex identification model. The strongest model consisted of bill depth (0.79, P< 0.0001) and bill tip to the back of the head (0.05, P = 0.1573) which were both found to be larger in males. The final portion of this study concerned roadrunner nest site selection. Data were collected in Wilbarger County, Texas from May 2006 to October 2009. A predictive logistic regression model of nesting locations determined that mesquite nesting tree (-0.89, P = 0.0064), oval tree shape (1.58, P = 0.0118), mesquite density (-0.004, P = 0.0080), and topographic edge (1.37, P = 0.0027) were the best predictors in determining actual nest sites from random locations.
219

Parasite-host interactions in an arctic goose colony

Harriman, Vanessa Brooke 02 January 2007 (has links)
The arctic is currently experiencing some of the greatest rates of warming. Newly emerging diseases in the arctic are of particular interest due to the implications these may have at southern latitudes if temperatures continue to rise around the globe. It is important to document changes in pathogen populations, such as alterations in range, virulence, prevalence, and abundance, and the effect these may have on their host populations. Parasites influence the reproductive success of their hosts in some cases. Studies on impacts of ectoparasites on avian reproductive success have generally been focused on species with altricial young. I studied the abundance of an apparently newly emerging nest-parasite and the effects of this parasite on Rosss (<i>Chen rossii</i>) and lesser snow goose (<i>Chen caerulescens caerulescens</i>) reproductive success in the Karrak Lake goose colony, Nunavut, Canada from 2001 to 2004. <p>The nest parasite, identified as the flea <i>Ceratophyllus vagabundus vagabundus</i>, was associated with goose eggs covered with spots of blood. The proportion of goose egg-shells covered by blood was positively correlated with flea abundance in the nest. This relationship allowed the use egg blood-coverage as an index of flea abundance for remaining analyses. Flea abundance in goose nests was associated with variables associated with the host and the hosts habitat. I used general linear models in conjunction with Akaikes information criterion (AIC) to determine which factors were most important in influencing flea abundance in goose nests. The most parsimonious model to explain the relationship between egg blood coverage and flea abundance in goose nests included goose clutch size, age of nest bowl (new vs. old), history of nesting by geese on a specific plot within the colony, habitat within 0.5m of nest, and year. The best predictor of flea abundance was the age of the nest bowl, with nest bowls re-used by geese containing more fleas than new bowls. This relationship was expected as fleas over-wintered in goose nests at the Karrak Lake colony.<p> Logistic regression and AIC were used to determine whether egg blood-coverage was an important variable influencing nest success. All top five models included blood-coverage. Goose nest success was negatively influenced by fleas in most years. There was a threshold of egg blood-coverage at which nest success was affected, and this threshold varied, with >20% blood indicating a significant decline in nest success in two years, and >5% blood-coverage indicating a decrease in nest success in one year. To my knowledge, this is the first study that has examined the parasites of avian nests in an arctic ecosystem and was also the first to investigate the effect of nest parasites on birds with precocial young. More research is needed to determine what factors limit this flea population and whether fleas may become a regulating factor for geese in the Karrak Lake colony.
220

Breeding biology and habitat associations of the Altamira Oriole and Northern Beardless-Tyrannulet in the Lower Rio Grande Valley, Texas

Werner, Scott Michael 15 November 2004 (has links)
I studied the breeding biology and nesting ecology of the Altamira Oriole (Icterus gularis) and Northern Beardless-Tyrannulet (Camptostoma imberbe), two songbirds inhabiting remnant tracts of Tamaulipan brushland of the Lower Rio Grande Valley, Texas during 2002-2003. I found 76 active oriole nests, 7 of which were reused for second broods, for a total of 83 nesting attempts. I estimated that nearly 20% of the oriole breeding population were subadult, or second-year orioles, which is extremely rare for this species. Oriole breeding pairs were found in high densities and may be at their highest level at the study sites since the 1970s. Fifty-nine percent of oriole nests fledged, and 37% failed. Six nests produced Bronzed Cowbird (Molothrus aeneus) fledglings. Vegetation analysis suggests that orioles prefer the tallest trees at the sites in which to place their nests. A greater number of fallen logs near the nest was also a predictor of nest sites, which suggests that orioles prefer scattered woodlands, but also that many of the forests probably continue to shift to a more open, thorn-scrub climax stage. I monitored 28 Northern Beardless-Tyrannulet nests, which were restricted to a smaller number of study tracts than Altamira Orioles. Historical records are lacking for Northern Beardless-Tyrannulets at these sites, but my surveys indicated that there were similar seasonal numbers of tyrannulets at some of the study sites as there were during 1996-1998. Forty-three percent of nests were successful and 57% failed. Higher abundances of epiphytic Spanish moss (Bromeliaceae: Tillandsia usneoides) and ball moss (Bromeliaceae: Tillandsia recurvata) were the most important predictors of nest sites. The continued existence of these two species in South Texas will depend upon the preservation of tall forests, and in the case of the tyrannulet, forests rich in Tillandsia epiphytes.

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