Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 65-71). Also available via the Internet.

Understanding regulation of wild animal populations is important in ecological investigations and applied wildlife management. Progress in understanding regulatory processes has been hindered by a long-running debate over the role of density-dependent and density-independent variables in population regulation. Population regulation of exploited species is of particular interest because harvest theory is predicated on assumptions of density-dependent feedback. However, for many exploited species, the functional relationships and mechanisms of population regulation via density dependence are not quantified (e.g., Northern bobwhite (Colinus virginianus). Compounding this task is the lack of a mechanistic understanding of the influence of density-independent factors in population regulation. The overall goal of this dissertation is to investigate the roles of density-dependent and density-independent processes in bobwhite populations. Bobwhites are an excellent species to investigate the role and influence of density-dependent and density-independent factors due to their unique life history, wherein they can exhibit density dependence in survival, reproduction, or both. I provide support for the concomitant influence of density-dependent and density-independent processes operating to regulate bobwhite populations. My results support the importance of food and cover and the additive influence of density-dependent and density-independent factors on bobwhite annual survival. I also report evidence for the differential effects of covariates on survival phases. My results represent the first evidence of support for the Tub and Tap hypotheses on bobwhite survival. I also quantify a density-dependent effect on bobwhite recruitment. Collectively, these results provide new evidence for understanding the role of internal and external factors in bobwhite populations.

no abstract provided by author / Master of Science

M.S.

M.S.

Home range, habitat use, and movements of reintroduced masked bobwhite (Colinus virginianus ridgewayi) were studied during 1986-88 on the Buenos Aires National Wildlife Refuge in southern Arizona. Home ranges averaged 10.9 ha (5.2-14.6 ha), and core areas averaged 1.1 ha (0.2-2.7 ha). Core areas had significantly higher visual obstruction by vegetation from 0-1 dm, aerial and basal grass cover, and significantly lower bare ground, litter, half-shrub cover, half shrub density, and visual obstruction by vegetation from 5-20 dm than non-core areas. The majority of the masked bobwhite moved less than 1 km between their release location and the site of first trapping. However, some long distance movements occurred. Once home ranges were established, masked bobwhite seldom left the boundaries. Key habitat components are identified for masked bobwhite on the Buenos Aires National Wildlife Refuge.

BACKGROUND: A systems toxicology investigation comparing and integrating transcriptomic and proteomic results was conducted to develop holistic effects characterizations for the wildlife bird model, Northern bobwhite (Colinus virginianus) dosed with the explosives degradation product 2-amino-4,6-dinitrotoluene (2A-DNT). A subchronic 60d toxicology bioassay was leveraged where both sexes were dosed via daily gavage with 0, 3, 14, or 30 mg/kg-d 2A-DNT. Effects on global transcript expression were investigated in liver and kidney tissue using custom microarrays for C. virginianus in both sexes at all doses, while effects on proteome expression were investigated in liver for both sexes and kidney in males, at 30 mg/kg-d. RESULTS: As expected, transcript expression was not directly indicative of protein expression in response to 2A-DNT. However, a high degree of correspondence was observed among gene and protein expression when investigating higher-order functional responses including statistically enriched gene networks and canonical pathways, especially when connected to toxicological outcomes of 2A-DNT exposure. Analysis of networks statistically enriched for both transcripts and proteins demonstrated common responses including inhibition of programmed cell death and arrest of cell cycle in liver tissues at 2A-DNT doses that caused liver necrosis and death in females. Additionally, both transcript and protein expression in liver tissue was indicative of induced phase I and II xenobiotic metabolism potentially as a mechanism to detoxify and excrete 2A-DNT. Nuclear signaling assays, transcript expression and protein expression each implicated peroxisome proliferator-activated receptor (PPAR) nuclear signaling as a primary molecular target in the 2A-DNT exposure with significant downstream enrichment of PPAR-regulated pathways including lipid metabolic pathways and gluconeogenesis suggesting impaired bioenergetic potential. CONCLUSION: Although the differential expression of transcripts and proteins was largely unique, the consensus of functional pathways and gene networks enriched among transcriptomic and proteomic datasets provided the identification of many critical metabolic functions underlying 2A-DNT toxicity as well as impaired PPAR signaling, a key molecular initiating event known to be affected in di- and trinitrotoluene exposures.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Basic knowledge of the ecology of bobwhite quail, colinus virginianus (L.), on the Salamonie Reservoir Area, Huntington and Wabash Counties, Indiana, was gathered during 1970-1975. The bobwhite is a major gamebird species on the Salamonie Reservoir Area even though the resident populations of this non-migratory bird tend to remain relatively low. Bobwhites have been extensively studied in other parts of their range but little has been done in this marginal habitat region of northeastern Indiana. A basic knowledge of bobwhite ecology in this region is necessary in order to formulate management plans calculated to increase the population level.The whistling cock count technique was used to determine a call index from the average mean calls per stop. This technique correlated significantly with hunter success (P<0.05) but call indices from the highest count day, during the six-year period, correlated most significantly (P<0.001) with hunter success.An average of 50.2 percent cocks to 49.8 percent hens was found during the six-year study in 404 hunter-killed bobwhites and 36 bobwhites collected by me. Bobwhite weights averaged 179 g during the November months, 197 g during the December months, 205 g during the January months, and 185 g during the months of February and March. The mean average weight for the six-year study was 185 g. Age ratio, during the study months, was 3.66 young bobwhites to one adult. Age ratios were stable each November through March but they fluctuated annually during the six-year period with no consistant trend. Four major food items comprised 77.5 percent of volumetric contents found in bobwhite crops: corn, soybeans, wheat, and black locust seeds.Bobwhite population levels fluctuated during the six-year study. The population level appeared to have an inverse relationship with the number of small game hunting efforts on the Salamonie Reservoir Area when the small game hunting efforts numbered above 3,000.Bobwhites fed on black locust seeds during periods of snow cover. The availability of black locust seeds during winter months made this food source an important item for the survival of bobwhites on the Salamonie Reservoir Area.

Northern bobwhite (Colinus virginianus) populations have continually declined across much of their native range due to changes in land use and habitat. This notable decline causes concern for the future of this important game bird species and highlights the need for research on how habitat influences bobwhite vital rates. My research, conducted during 2018-2020 at Burning Star State Fish and Wildlife Area, addressed the following two objectives to provide information on how landcover characteristics influence bobwhite populations: (1) investigate how landcover characteristics influence annual bobwhite home range size, and (2) investigate how landcover characteristics influence bobwhite breeding season survival. For Objective 1, I radio-marked 113 individuals of which 50 bobwhites (31 males and 19 females) had ≥25 independent tracking locations and were used in my analyses. I modeled landcover types related to bobwhite habitat selection, habitat avoidance, foraging habitat, and protective cover to annual bobwhite home range size. Landcover types related to foraging habitat formed the most parsimonious model, with the proportion of grassland having the greatest negative influence on bobwhite home range size. As expected, landcover types that are thought to be beneficial to bobwhite fitness were negatively related to bobwhite home range size, suggesting those landcover types provide necessary resources for bobwhites throughout their full annual cycle. For Objective 2, I radio-marked 113 individuals of which 50 bobwhites (31 males and 19 females) had ≥25 independent tracking locations and were used in my analyses. I used a known fate model of the influence of landcover types, in a stepwise fashion, on bobwhite breeding season survival at two scales, home range and landscape. At the home range scale, the univariate model including early successional forest was the most parsimonious model, wherein the proportion of early successional forest negatively influenced bobwhite breeding season survival. Other competitive models included agriculture and early successional forest + scrub shrub where agriculture positively influenced breeding season survival while early successional forest and scrub shrub negatively influenced breeding season survival. The negative influence of landcover types thought to provide necessary protective cover for bobwhites on breeding season survival is inconsistent with the current paradigm that woody cover is an important habitat component that provides protective and escape cover, thermoregulatory functions, and midday loafing sites for bobwhites. Early successional forest provides visually appealing woody protective cover but appears to expose bobwhites to a higher predation risk because trees provide perch habitat for avian predators. Agriculture positively influenced breeding season survival because during the breeding season, agriculture provides overhead cover and bare ground that provides protective cover, foraging opportunities, and enables ease of movement. At the landscape scale, the null model was the most parsimonious model, but there was weak evidence that the proportion of grassland positively influenced breeding season survival. My study demonstrates how landcover composition influences annual home range size and breeding season survival at different scales.