Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xii, 73 p. : ill. (some col.), map (some col.). Vita. Includes abstract. Includes bibliographical references.

No description available.

No description available.

Considering the high reproductive investment of the social male and the cost to the female of losing this benefit by soliciting copulations outside the social pair bond, it is expected that most raptor populations would exhibit low to no occurrence of extra-pair paternity (EPP). This holds true for the majority of raptor species studied to date with only one exception of an urban Cooper's hawk (Accipiter cooperii) study which reported an unexpectedly high extra-pair young frequency of 19.29%. In our study we examined the frequency of EPP within a red-shouldered hawk (Buteo lineatus) population residing in the suburban/urban matrix of southwest Ohio. During the breeding seasons of 2018 and 2019, 181 breeding age and nestling individuals were color-banded and sampled for genetic analysis using nine microsatellite loci. After genotyping a total of 40 broods (with at least two nestlings per brood) and both presumptive parents of each brood, no clear evidence of EPP was detected. However, at one nest site, the entire brood of four chicks was not sired by the adult male observed during the courtship period, nor another adult male observed tending the chicks later in the season. We suspect that this particular nest represented two instances of rapid mate replacement rather than extra-pair fertilization by a third unsampled male, because none of the chicks were sired by either of the two adult males observed at the nest. We also reviewed potential factors contributing to our finding of overall genetic monogamy in our study population in comparison to other raptor taxa EPP studies. Our results suggested that factors other than habitat composition alone play an important role in determining the type of breeding strategy exhibited by different raptor populations.

Plastic pollution is unavoidable in the natural environment. Consequences of plastic ingestion include exposure to environmental pollutants and toxin accumulation, causing endocrine disruption, inflammatory and physiological stress in organisms. Microplastics have been shown to transfer across food webs, however, limited studies have examined microplastic accumulation across terrestrial food webs. Furthermore, few studies have examined plastic pollution in apex predatory animals. A study was conducted to quantify the abundance of plastic pollution in the gastrointestinal tract in birds of prey. Two species were investigated, one which forages in terrestrial habitats and one which forages in aquatic environments including Buteo lineatus (red-shouldered hawk) and Pandion haliaetus (osprey), respectively. The gastrointestinal tract was necropsied, chemically digested, and examined for microplastic prevalence. Overall, microplastics are significantly more abundant per gram of gastrointestinal (GI) tract tissue in species that forage on small rodents and terrestrial reptiles (B. lineatus) as compared to species that forage on fish and aquatic invertebrates (P. haliaetus). Buteo lineatus averaged 0.81 (±0.15) fibers and 0.14 (±0.04) fragments per gram of GI tract tissue while P. halieatus averaged 0.31 (±0.09) fibers and 0.04 (±0.02) fragments per gram of GI tract tissue. There was a significant interaction between type and color in both B. lineatus and P. haliaetus GI tract tissues. Micro-Fourier-transform infrared spectroscopy (μ-FTIR) was run on haphazardly selected samples and found that rayon was the most common polymer identified in both species. The significant difference found between species could be indicative that terrestrial raptors may experience greater bioaccumulation than aquatic species foraging at comparable trophic levels. However, the significant interaction between type and color in both species indicates a potential common source of pollution that affects both environments. Further investigation on the source of polymers is necessary in order to develop conservation and management strategies aimed at decreasing the output of synthetic fibers into the environment. Due to the abundance of polymers found in these species, understanding the potential biological and physiological effects of plastics is essential to informing superior management strategies that can better protect and preserve wildlife from increasing anthropogenic pressures.

Telemetry triangulation provides an estimate of a radio-tagged animal’s location that is influenced by various time and site-specific factors that can cause errors. If these errors are not considered when using location data, the conclusions drawn about animal behavior such as habitat use might be misleading. I determined home range and habitat use and selection characteristics of red-shouldered hawks (Buteo lineatus) in central Maryland. The effects of telemetry triangulation errors on these characteristics were examined. Red-shouldered hawk location estimates were obtained by triangulation to radio-tagged birds. Point estimates were determined by using ≥3 azimuths. A confidence ellipse was calculated around each point estimate which represented the error area associated with that point estimate. From the distribution of possible points within the error area of each point estimate, sampled points (simulated points) were generated for use in additional analyses to assess telemetry error. Home range sizes, based on point estimates and simulated point estimates were delineated using the convex polygon and harmonic mean models. Habitat occurrence was described from a digitized cover type map. Average home range sizes based on point estimates and simulated point estimates for 3 male hawks were larger than average home range areas for 2 female hawks. There were differences detected between pooled point estimate home range sizes and the pooled simulated point estimate home range sizes. There were fewer differences in home range sizes based on the harmonic mean model than the convex polygon. No significant seasonal differences were found for point estimate or simulated point estimate home range Sizes. Seasonal habitat use did not vary based on pooled data from all hawks on PWRC. Bottomland forest was the most frequently used habitat type; however, water habitats (ponds and river) were the most frequently selected. Bottomland forests, river swamps, terrace/bluff forests, residential/structural areas, seepage swamps, pine forests, and pine/oak forests were selected occasionally by most hawks. The two most infrequently selected habitats were powerlines and upland oak forests. / Master of Science

abstract: Once considered an abundant species in the eastern United States, local populations of red-shouldered hawks, Buteo lineatus, have declined due to habitat destruction. This destruction has created suitable habitat for red-tailed hawks, Buteo jamaicensis, and therefore increased competition between these two raptor species. Since suitable habitat is the main limiting factor for raptors, a computer model was created to simulate the effect of habitat loss in central Maryland and the impact of increased competition between the more aggressive red-tailed hawk. These simulations showed urban growth contributed to over a 30% increase in red-tailed hawk habitat as red-shouldered hawk habitat decreased 62.5-70.1% without competition and 71.8-76.3% with competition. However there was no significant difference seen between the rate of available habitat decline for current and predicted development growth. / Dissertation/Thesis / M.S. Applied Biological Sciences 2011