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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.
381

Habitat suitability of the yellow rail in south-central Manitoba

Martin, Kristen 21 September 2012 (has links)
Little is known about the distribution and habitat suitability of yellow rails (Coturnicops noveboracensis) throughout their breeding range. Yellow rail and vegetation surveys were conducted at 80 wetlands in south-central Manitoba in 2010-2011 to evaluate the effectiveness of repeat-visit, call-broadcast night surveys for detecting this species and habitat associations of this species at the 3-km landscape, patch, and plot scales. Yellow rails were detected at 44% of the study wetlands. Yellow rail detection was imperfect (0.63 in each year), but call-broadcast increased the number of yellow rails detected. Future yellow rail survey efforts should employ call-broadcast and at least three surveys per survey point. Yellow rail presence was positively influenced by the amount of marsh/fen in the landscape and the proportion of rushes at the study wetlands. These characteristics should be considered when identifying potential yellow rail habitat in south-central Manitoba.
382

Trimatė tekstilinė kompozicija „PAUKŠČIU PAKILSIU“ / Three-dimensional textile composition“I'LL FLUSH LIKE A BIRD”

Myniotė, Gita 02 July 2012 (has links)
Bakalauro darbe analizuojami paukščio įvaizdžio raiškos ypatumai senojoje ir šiuolaikinėje lietuvių tekstilėje, siekiant sukurti trimatę tekstilės kompoziciją PAUKŠČIU PAKILSIU. Pasirinkta kurti trimatė kompozicija, manau, labai tinkama gvildenti ir interpretuoti ugdymo procese, kadangi suteikia papildomų galimybių per etninės kultūros aspektus, viena vertus, geriau pažinti šiuolaikinį meną, o kita vertus prisidėti prie ekologinio mokinių ugdymo. / The Bachelor's paper analyses the peculiarities of a bird's image expression in antique and modern Lithuanian textile with a view to create a three-dimensional textile composition I'LL FLUSH LIKE A BIRD. The chosen three-dimensional composition, in our opinion, is very suitable for ventilation and interpretation in the educational process, whereas, through the aspects of ethnic culture, it provides additional possibilities, on the one part, to understand better the contemporary art and, on the other part, to contribute to the environmentally friendly education of pupils.
383

EVALUATING A NOVEL ENDOPHYTIC GRASS FOR ITS POTENTIAL TO REDUCE INVERTEBRATE POPULATIONS AND ASSOCIATED BIRD STRIKE RISK AT AIRPORTS

Miller, Diana M 01 January 2015 (has links)
Aircraft strikes are a significant safety hazard on airports worldwide. Wildlife management at airfields is the most effective tactic to reduce airstrike risk – to modify the habitat to be undesirable to animals. Tall fescue grasses containing a fungal symbiont may serve that purpose. They produce alkaloids that convey resistance to some grass-feeding invertebrates, which might in turn reduce incidence of insectivorous birds. A commercial endophytic grass (Avanex™) consisting of ‘Jackal’ tall fescue infected with a unique endophyte (AR 601) is purported to contain especially high levels of alkaloids and to reduce bird populations if planted at airports. I evaluated it against the common KY31 tall fescue with its wild-type endophyte for invertebrate and vertebrate deterrence. Invertebrate abundance, survival, growth, and development were generally similar on Jackal E+ or KY31 E+. Spanish goats and wild birds showed no avoidance of Jackal E+, nor did Jackal E+ contain significantly higher levels of alkaloids than did KY31 E+. The Avanex™ tall fescue was not any better than KY31 in deterring herbivores but the concept is sound. However, better understanding of the relationship between grass, endophyte, alkaloid, and herbivore is needed to inform how such grasses might be used to reduce bird strike hazard.
384

Life-history traits and potential causes of clutch-size decline in the introduced song thrush (Turdus philomelos) in New Zealand

Congdon, Nicola Maree January 2010 (has links)
The song thrush (Turdus philomelos) was introduced to New Zealand from Britain during the mid 19th century and has become one of the most common terrestrial bird species in New Zealand. In this study, I surveyed a range of life-history traits in New Zealand song thrushes for comparison with traits of British thrushes. Clutch size, egg size and nest size have decreased, while the nestling period is shorter and the incubation period longer. This combination of changes suggests birds are investing less energy into each reproductive bout. Birds also appear unable to raise large broods, as nestling starvation is common in New Zealand, which suggests that food is limiting. I experimentally tested the ability of song thrushes to incubate enlarged clutches and broods, but productivity was not higher for enlarged broods and natural 3- and 4-egg clutches produced similar numbers of fledglings. Thus reduced clutch size may be an adaptation to the local environment. Differences in female incubation behaviour, with 3- and 4-egg clutches receiving higher levels of incubation and more visits per hour than 5-egg clutches, also suggest New Zealand thrushes have difficulty coping with clutches as large as those in Britain. The decrease in clutch size between New Zealand and Britain is in the direction and magnitude expected based on the change in latitude, which supports the hypothesis that factors affecting foraging time and food availability, such as daylength, temperature and rainfall, may be selecting for smaller clutches. Egg size was also found to have decreased in New Zealand, though this may be the result of smaller adult size. Hatchling mass was related to egg volume, but I found no effect of egg volume or clutch size on hatching success. However, nests containing more pointed eggs (i.e., abnormally-shaped eggs), had lower survival and hatching/fledgling success. Data from the national nest record database and my study both suggest that differences in song thrush productivity are the result of differential survival of nestlings. Nestling mortality due to starvation was common at Kowhai Bush, but rare in Britain, so either adult condition or food availability may be lowering reproductive success in New Zealand. High rates of nest failure (>65%) could also affect clutch size, but the strong directional selection imposed by food limitation during the nestling period suggests that increases in food supply would result in increased reproductive success even with the same levels of nest failure. When comparing clutch size throughout New Zealand, I found a significant, positive relationship with rainfall, which further suggests that food limitation may be the main factor driving changes in life-history traits of song thrushes in New Zealand.
385

The effects of prescribed surface fire on ground- and shrub-nesting nearctic migrants at Fork Ridge, Hoosier National Forest, 1996 and 1997

Aquilani, Steven M. January 1998 (has links)
During autumn 1993, the U. S. Forest Service began implementing a program of prescribed surface fire in the Fork Ridge region of Hoosier National Forest. To determine the effects of the prescribed surface fire on ground- and shrub-nesting nearctic migrants, I conducted vegetation structure sampling, bird abundance surveys, and nest searches during the 1996 and 1997 breeding seasons. The prescribed surface fire drastically reduced understory vegetative cover from 0.0 to 2.5 m above ground and the density of live stems < 5.0 cm dbh. Herbaceous cover < 0.5 m tall in the burned site returned to levels similar to the unburned site within 2 years of the burn.Prescribed burning had little effect on overall avian species diversity, but altered the community composition. In 1996, there were 12 species present in the unburned site which were absent in the burned site and 9 species present in the burned site which were absent in the unburned site. In 1997, there were 9 species present in the unburned site which were absent in the burned site and 7 species present in the burned site which were absent in the unburned site. As a guild, ground- and shrub-nesting nearctic migrants and residents were less abundant in the burned site compared to the unburned site. Conversely, species such as Indigo Buntings (Passerina cyanea) and White-breasted Nuthatches (Sitter carolinensis) were more abundant in the burned site.Nests in the burned site had a 25% success rate, whereas nests in the unburned site had a 44% success rate. Nest parasitism did not differ between the burned site (1.2 cowbird eggs/nest) and unburned site (0.9 cowbird eggs/nest). Worm-eating Warblers (Helmitheros vermivorus) were the only ground- and shrunb-nesting nearctic migrant found in the burned site. Worm-eating Warbler nests in the burned site were characterized as having greater understory cover than surrounding burned areas. My results suggest that prescribed surface fires in Fork Ridge may be negatively impacting some ground- and shrub-nesting migrants by altering nesting habitat. / Department of Biology
386

Population response of a declining songbird to silviculture : how cerulean warbler (Setophaga cerulea) territory size and settlement patterns fare in the face of forest disturbance

Dibala, Ryan H. 22 May 2012 (has links)
Over the past five decades, populations of the Cerulean Warbler (Setophaga cerulea) have declined precipitously and the response of populations to silviculture has been identified as a high-priority research need. This species was studied in nine forest management units in Southern Indiana following a harvest that took place in 2008. Males were detected, territories were demarcated, and male age-class was determined to identify settlement patterns. Vegetation was measured in all territories and associated random non-use sites. Data analyzed in ArcMap (ArcGIS 10) show that Cerulean Warbler territory size was smallest and density was highest in even-aged units. Territories contained a greater number of small woody species than non-use sites but no vegetative differences existed between male age-classes. Instead, males appeared to select areas by relying on social cues from experienced neighbors. It is possible that “social attraction” management techniques could influence male Cerulean Warbler settlement patterns, providing a valuable tool for the conservation of this species. / Forest management effects on cerulean warbler territory size in southern Indiana -- Conspecific social cues strongly influence cerulean warbler male settlement patterns in a managed forest. / Department of Biology
387

Assessment of organic pollutants in selected wild and domesticated bird eggs from Gauteng, South Africa / Laura Penelope Quinn

Quinn, Laura Penelope January 2010 (has links)
Polybrominated flame retardants (BFRs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were analysed in eggs of various wild bird species from industrialised areas in South Africa. Eggs were collected during the 2008 – 2009 breeding season, homogenised and sent to the Norwegian School of Veterinary Science (NVH) for gas chromatography-mass spectrometry (GC-MS) analysis. The concentration, contamination profile, and risk assessment were conducted for each pollutant class, while effects of species-specific variation, feeding guild, and feeding habitat were investigated. Levels of BFRs ranged between 2.6 – 44 ng g-1 wet mass (wm). The predominant congeners were BDE-153, -154, - 183 and -47. Results indicated species, in close contact to humans, had higher levels of BFRs, even at lower trophic levels. Therefore, diet was not the primary route of exposure. High concentrations and the occurrence of nona-PBDE congeners and HBCD indicated exposure to current use BFRs. There were measurable levels of OCPs and PCBs in all eggs analysed. Median OCP concentration ranged from 4.2 – 623 ng g-1 wm. DDE was the predominant compound in all species with the exception of the Crowned Lapwing (Vanellus coronatus) where chlordanes were predominant. This may indicate a species-specific attribute in the metabolic efficiency or diet of the genus, since these findings have been reported elsewhere in literature. Congener profiles indicated historic sources of lindane and DDT, while low levels of p,p’-DDT in al species indicate long-range or atmospheric transport. Even though levels of p,p’-DDE were approaching toxicological thresholds, no eggshell thinning was evident. Concentrations of OCPs and PCBs showed an increase with increasing tophic level. PCB concentrations ranged between 0.9 – 296.4 ng g-1 wm. When studying the metabolic potential of PCBs, metabolic groups showed good agreement with the biodegradability of the individual congeners. Phenobarbital-type (PB-type) inducer PCBs were prevalent, indicating the predominance of less toxic PCB congeners. However, non-ortho PCBs were not analysed. These congeners aslo could impact on the toxic potential of PCBs in wild bird eggs. Principle component analysis (PCA) indicated that variances within datasets could be attributed to congener profiles within species as they were affected by exposure, diet, position in the food web, and association with human activities. Although the individual groups of organohalogens were below no observed effect levels (NOELs), negative effects could occur through interactions of various compounds with each other, as well as the unique exposure profiles of South African bird populations. To assess the dietary exposure of low-income human populations living close to large industries, the occurrence of organohalogens was investigated in backyard chicken eggs. Levels of dioxins in these eggs were above the European Union (EU) recommended limits, whereas BFRs and OCPs levels were below levels of concern. Nevertheless, areas where DDT is actively applied to dwellings for malaria control should be urgently investigated. The presence of measureable levels of all the compounds considered, indicate an environment seriously impacted by anthropogenic activity that in the long term could negatively affect both the environment and human health, if it has not already done so. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2011.
388

Effects of Habitat Change on Bird Species Richness in Ontario, Canada

De Camargo, Rafael Xavier 24 October 2013 (has links)
It is generally assumed that when natural habitat is converted to human-dominated cover such area is “lost” to its native species. Extinctions will ensue. The literature generally assumes that species are extirpated as natural area is reduced, following the well-known species-area relationship (SAR). However, SARs have consistently over-estimated species losses resulting from conversion of natural habitat to human-dominated land covers. We hypothesize that the overestimation occurs because these area-based models assume that converted habitat is “lost”, eliminating all species. However, in the real world, conversion of natural land cover to human-dominated cover frequently produces new land covers, different from the original habitat, but not necessarily completely inhospitable to biodiversity. We evaluated the responses of total avian richness, forest bird richness and open habitat bird richness to remaining natural area within 991 quadrats, each 100 km2, across southern Ontario. Total bird species richness does not follow SAR predictions; rather, the number of bird species peaks at roughly 50% natural land cover. The richness of forest birds does follow the usual SAR power-law as a function of forested area. In contrast, richness of birds that prefer open-habitat does not increase monotonically with either natural- or human-dominated land cover. However, we can partition human-dominated land cover into an “available human-dominated” component and “lost” habitat. Richness of open-habitat species relates to the amount of available human-dominated cover. Distinguishing three habitat types (natural, available human-dominated, and lost) permits accurate predictions of species losses in response to natural habitat conversion.
389

Habitat suitability of the yellow rail in south-central Manitoba

Martin, Kristen 21 September 2012 (has links)
Little is known about the distribution and habitat suitability of yellow rails (Coturnicops noveboracensis) throughout their breeding range. Yellow rail and vegetation surveys were conducted at 80 wetlands in south-central Manitoba in 2010-2011 to evaluate the effectiveness of repeat-visit, call-broadcast night surveys for detecting this species and habitat associations of this species at the 3-km landscape, patch, and plot scales. Yellow rails were detected at 44% of the study wetlands. Yellow rail detection was imperfect (0.63 in each year), but call-broadcast increased the number of yellow rails detected. Future yellow rail survey efforts should employ call-broadcast and at least three surveys per survey point. Yellow rail presence was positively influenced by the amount of marsh/fen in the landscape and the proportion of rushes at the study wetlands. These characteristics should be considered when identifying potential yellow rail habitat in south-central Manitoba.
390

Assessment of organic pollutants in selected wild and domesticated bird eggs from Gauteng, South Africa / Laura Penelope Quinn

Quinn, Laura Penelope January 2010 (has links)
Polybrominated flame retardants (BFRs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were analysed in eggs of various wild bird species from industrialised areas in South Africa. Eggs were collected during the 2008 – 2009 breeding season, homogenised and sent to the Norwegian School of Veterinary Science (NVH) for gas chromatography-mass spectrometry (GC-MS) analysis. The concentration, contamination profile, and risk assessment were conducted for each pollutant class, while effects of species-specific variation, feeding guild, and feeding habitat were investigated. Levels of BFRs ranged between 2.6 – 44 ng g-1 wet mass (wm). The predominant congeners were BDE-153, -154, - 183 and -47. Results indicated species, in close contact to humans, had higher levels of BFRs, even at lower trophic levels. Therefore, diet was not the primary route of exposure. High concentrations and the occurrence of nona-PBDE congeners and HBCD indicated exposure to current use BFRs. There were measurable levels of OCPs and PCBs in all eggs analysed. Median OCP concentration ranged from 4.2 – 623 ng g-1 wm. DDE was the predominant compound in all species with the exception of the Crowned Lapwing (Vanellus coronatus) where chlordanes were predominant. This may indicate a species-specific attribute in the metabolic efficiency or diet of the genus, since these findings have been reported elsewhere in literature. Congener profiles indicated historic sources of lindane and DDT, while low levels of p,p’-DDT in al species indicate long-range or atmospheric transport. Even though levels of p,p’-DDE were approaching toxicological thresholds, no eggshell thinning was evident. Concentrations of OCPs and PCBs showed an increase with increasing tophic level. PCB concentrations ranged between 0.9 – 296.4 ng g-1 wm. When studying the metabolic potential of PCBs, metabolic groups showed good agreement with the biodegradability of the individual congeners. Phenobarbital-type (PB-type) inducer PCBs were prevalent, indicating the predominance of less toxic PCB congeners. However, non-ortho PCBs were not analysed. These congeners aslo could impact on the toxic potential of PCBs in wild bird eggs. Principle component analysis (PCA) indicated that variances within datasets could be attributed to congener profiles within species as they were affected by exposure, diet, position in the food web, and association with human activities. Although the individual groups of organohalogens were below no observed effect levels (NOELs), negative effects could occur through interactions of various compounds with each other, as well as the unique exposure profiles of South African bird populations. To assess the dietary exposure of low-income human populations living close to large industries, the occurrence of organohalogens was investigated in backyard chicken eggs. Levels of dioxins in these eggs were above the European Union (EU) recommended limits, whereas BFRs and OCPs levels were below levels of concern. Nevertheless, areas where DDT is actively applied to dwellings for malaria control should be urgently investigated. The presence of measureable levels of all the compounds considered, indicate an environment seriously impacted by anthropogenic activity that in the long term could negatively affect both the environment and human health, if it has not already done so. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2011.

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