Browsing by Subject "Birds"
Now showing 1 - 10 of 10
Results Per Page
Sort Options
Item Avian-locust interactions in eastern Australia and the exposure of birds to locust control pesticides(Texas Tech University, 2005-12) Szabo, Judit K.; Astheimer, Lee; Hooper, Michael J.; Buttemer, William A.; McMurry, Scott T.There is growing worldwide pressure to develop new and effective chemicals against agricultural pests. Unfortunately, many pesticides have unanticipated and undesired effects on the environment. In eastern Australia, the Australian Plague Locust Commission (APLC) has responsibility for locust control, currently using three pesticides (fenitrothion, fipronil and the fungal agent, Metarhizium) to limit locust populations during outbreaks. In an effort to evaluate the potential impact of these practices on Australian native fauna, this dissertation aims to assess the probability of pesticide exposure in 285 avian species, due primarily to their co-occurrence with locusts in areas where pesticide treatments are most likely to occur. Due to the unpredictable nature of rainfall, locust outbreaks and control events, I have taken a landscape approach to this question, with the area of interest coincident with the area of responsibility of the APLC. Rainfall, vegetation and soil characteristics strongly influence locust and avian distributions. I have examined spatial and temporal patterns in these factors, as well as the relationships between them with a final aim of evaluating their impact on the spatio-temporal distribution of three locust species, locust control events and avian distributions. Avian species distributions were obtained by applying generalized linear models to presence/absence data for the areas of interest for the years 1998–2002. Probabilities of a bird species present at times and locations of locust control applications were calculated. Field observations of avian species’ occurrence and behavior during locust outbreaks were used to evaluate the model. In the last step, the risk of exposure to fipronil was evaluated considering fipronil levels in three avian food items, seed, vegetation and locust samples. Small granivorous birds consuming high amounts of food daily relative to their body weight are predicted to be at greatest risk from exposure.Item Avian-locust interactions in eastern Australia and the exposure of birds to locust control pesticides(2005-12) Szabo, Judit K.; Astheimer, Lee; Hooper, Michael J.; Buttemer, William A.; McMurry, Scott T.There is growing worldwide pressure to develop new and effective chemicals against agricultural pests. Unfortunately, many pesticides have unanticipated and undesired effects on the environment. In eastern Australia, the Australian Plague Locust Commission (APLC) has responsibility for locust control, currently using three pesticides (fenitrothion, fipronil and the fungal agent, Metarhizium) to limit locust populations during outbreaks. In an effort to evaluate the potential impact of these practices on Australian native fauna, this dissertation aims to assess the probability of pesticide exposure in 285 avian species, due primarily to their co-occurrence with locusts in areas where pesticide treatments are most likely to occur. Due to the unpredictable nature of rainfall, locust outbreaks and control events, I have taken a landscape approach to this question, with the area of interest coincident with the area of responsibility of the APLC. Rainfall, vegetation and soil characteristics strongly influence locust and avian distributions. I have examined spatial and temporal patterns in these factors, as well as the relationships between them with a final aim of evaluating their impact on the spatio-temporal distribution of three locust species, locust control events and avian distributions. Avian species distributions were obtained by applying generalized linear models to presence/absence data for the areas of interest for the years 1998–2002. Probabilities of a bird species present at times and locations of locust control applications were calculated. Field observations of avian species’ occurrence and behavior during locust outbreaks were used to evaluate the model. In the last step, the risk of exposure to fipronil was evaluated considering fipronil levels in three avian food items, seed, vegetation and locust samples. Small granivorous birds consuming high amounts of food daily relative to their body weight are predicted to be at greatest risk from exposure.Item Dynamical models of cranial kinesis(Texas Tech University, 2002-05) Miller, Stephanie S.This work is concerned with the modeling of the movement of the upper or lower jaw of a bird with respect to the brain case. This functional property is known as cranial kinesis. The skeletal elements of the jaw are modeled as a system of articulating rigid links and elastic structures. The Euler-Lagrange equations of motion for the joint angles are derived while accounting for external inputs that correspond to applied torques at selected nodes. Computer algebra manipuations are utilized to derive the state equations, and numerical solutions are computer. Simulations are carried out in order to illiustrate the effects of various system parameters that correspond to variations in anatomical structure.Item Guild-specific responses of birds to habitat fragmentation : evaluating the effects of different coffee production systems in Colombia(2011-12) LaRota-Aguilera, Maria Jose; Young, Kenneth R.; Miller, JenniferHabitat loss and fragmentation are the main drivers of biodiversity loss, especially in the tropics, where the transformation of forested areas into agriculture is predicted to increase dramatically in the next five decades. Although several studies have elucidated the negative impacts of agriculture on biodiversity, recent work suggests that some agro-ecosystems, such as coffee plantations, are potential key environments for maintaining biodiversity and ecosystem services. This study evaluated the role of different coffee production types (sun-exposed, semi-shade and shade in polycultures or monocultures) on the bird communities associated with these agro-ecosystems in the tropical Andes of Colombia. It used a guild-specific approach and nonparametric statistical methods to identify the influence of particular environmental, ecological and landscape variables on the bird community assemblage and to assess potential changes in the species composition among management type. The potential responses of avifauna to fragmentation were studied from three different perspectives: i) from a patch-level point of view, evaluating the effect of local habitat factors (e.g. canopy cover, type of crop and crop management type); ii) from a species point of view, evaluating the role of species ecological traits (e.g. feeding habitat); and iii) from a landscape point of view, evaluating the effect of landscape configuration variables (e.g. patch area and perimeter length). The results indicated that polyculture and shade coffee crops host the most diverse avian communities and that guild representativeness varied among different coffee crop types. The type of coffee production type and the habitat characteristics associated with them seemed to have the greatest influences on families such as flycatchers, hummingbirds and wrens. Finally, coffee plantations can potentially contribute to the maintenance of bird diversity in anthropogenic landscapes; however these benefits are strongly influenced by the type of crop management. The maintenance of traditional coffee production (shade polyculture coffee) is recommended, and should be economically and socially encouraged.Item The iconography of Moche winged figures(2010-08) Earle, Wendy Rose; Bourget, Steve, 1956-; Guernsey, JuliaThe Moche fineline painting corpus contains hundreds of representations of winged figures, but these have never been analyzed as a group. This thesis is an investigation of these winged figures, focusing on iconographic methodology. I have identified and categorized representations of birds (ducks, the Falconidae family, owls,hummingbirds, vultures and condors, etc.), mammals (bats) and insects (dragonflies) in the fineline paintings. Special attention has been paid to genus and family, including the attributes and behaviors of these animals. This has yielded several important observations about how the Moche represented and linked winged figures. In the second part of this thesis I use semiotic analysis to consider winged figures as symbols rather than naturalistic representations. I also examine anthropomorphic winged figures, and analyze the interpretive possibilities and the implications of these interpretations.Item Impacts of prescribed burning on migratory and breeding birds on a costal barrier island(Texas Tech University, 1995-05) Van't Hul, Jerrad T.Prescribed burning has been used to modify and diversify habitat in both grassland and forest ecosystems. However, use of prescribed burning as a tool en coastal barrier islands characterized by a Spartina/Paspalum grassland has received httle attention. Coastal barrier islands along the Gulf of Mexico provide important step-ever habitat for many migratory bkd species. The alteration or disturbance of this habitat may aflfect how these species meet the cost of migration. I assessed the inq)act of prescribed binning en the local abundance and breeding habitat of resident and migratory bkd species at Matagorda Island National Wildlife Refiige and State Natural Area, Texas, 1993 and 1994. I located 12, 122 ha plots en the mid-island portion of Matagorda Island in the barrier flats and estabUshed 12-16 fixed-radius point count stations on each plot. Two plots were bumed in late August 1992 and 1993 (summer bums), two in early January 1993 and 1994 (winter bmns), and four plots served as controls. I used point count stations to measure vegetation variables and to conduct bkd surveys. I located and monitored nests to evaluate nest success en control and treatment areas. I also examined micrehabitat selection of breeding bkds at nest sites.Item Neotropical migrant and Chinuahuan desert bird community use of arroyo-riparian habitat and adjacent upland(Texas Tech University, 1995-05) Kozma, Jeffrey M.The Fort Bliss Military Reservation wishes to open the McGregor Missile Firing Range in south-central New Mexico to tracked vehicle maneuvers. The McGregor Range is comprised primarily of Chihuahuan Desert habitat. Arroyos punctuate the Range and provide important riparian stop-over and nesting habitat for migratory and resident birds. In this study, I determine the use of arroyo-riparian and surrounding upland habitat by both Neotropical migrants and resident breeding species, on the McGregor Missile Firing Range, Fort Bliss, Texas, in 1993 and 1994. I sampled migrating birds using mist-nets during March and April, and surveyed breeding birds using variable circular plot point counts during May and June, 1993 and 1994. I conducted nest searches during May and June, and sampled vegetation at bird survey points, nest sites and non-use nest sites. I evaluated the relationship between bird species diversity, species richness, and bird density with structural diversity of the vegetation as well as individual shrub species. I also compared vegetation between use and non-use nest sites to determine differences among macrohabitats.Item Rising selenium levels at Truscott Brine Lake, Truscott, Texas: hazardous or harmless to the avian community?(Texas Tech University, 1999-08) Wrinkle, Lisa G.Selenium (Se) occurs naturally as a trace element in most soils and rock and is an essential micronutrient that is important in several biological processes. However, excess amounts of selenium can be toxic, especially to wildlife. Selenium toxicity in animals results from drinking water or consuming plants or animals in places where contaminated water has entered the food chain. Biomagnification of selenium in the aquatic food chain can dramatically increase the dietary concentrations of the element available to fish and birds that consume aquatic organisms. Consequently, a small increase in waterbome selenium will yield a disproportionately large increase in selenium levels offish and wildlife. Concentrations of selenium in water may not be toxic, but biomagnification may cause toxicity in higher trophic levels.Item The Paleoclamatic Implications of the Avian and Mammalian Faunas of Lower Sloth Cave, Guadalupe Mountains, Texas(Texas Tech University, 1977-12) Logan, Lloyd EugeneNot Available.Item Urban bird conservation(2008-12) Fergus, Robby Scott; Doughty, Robin W.Birds have co-inhabited American cities since the colonial era, and as people have noticed and appreciated them, they have taken steps to make cities even more hospitable for them. This dissertation documents the history of birds in cities and efforts to create more bird-friendly urban areas. The examination starts with the commercial core of modern cities, moving outwards through the residential and industrial zones, taking note of parks and other urban oases as well as the transportation and communications networks that help shape and define American cities. Bird conservation activities in scattered cities across the country make each of these urban zones better for birds. The future of birds in American cities depends on how these zones are managed, and the ability of local governments, nonprofits, corporations, and bird enthusiasts working together to protect birds from hazards and provide additional habitat opportunities within the city.