We have been studying the population of Eastern Kingbirds breeding in riparian habitats in Malheur National Wildlife Refuge (eastern Oregon) since 2002. These efforts have created an ideal research environment wherein most adults in the population have been color banded and DNA sampled and, as part of other research projects, nearly all broods since 2003 have been paternity tested. I decided to use behavioral video recordings of parental nest behavior undertaken between 2003 and 2010 for two unrelated projects. First, I tested the effectiveness of video sampling nesting behavior (see below and chapter 2). Second, I tested whether male kingbirds were able to affect their level of paternal investment in accordance with their level or realized paternity (see below and chapter 3). Chapter 2 was split into three distinct questions: 1) are parental nesting behaviors repeatable, 2) is a one hour sample sufficient to capture variability in these behaviors, and 3) is the first hour of recording sufficient to capture variability in these behaviors. I found overwhelming evidence that the behaviors I measured were repeatable. This is truly important, for if repeatability was disproven, it would call into question the use of sampling throughout the field of animal behavior. I similarly found strong evidence that a one hour sample was sufficient to capture variability in parental behaviors. From this I was able to suggest that further sampling effort would be better spent increasing sample size rather than observation length. Testing whether the first hour of recording was sufficient to capture variability in parental behavior found more muddled results. While there generally was correlation between behavioral values in the first hour and those over a longer observation period, most behaviors were found to have significantly lower values in the first hour. I tested whether this was the result of a lingering observer effect or a natural effect of time of day and concluded that an observer effect was the more likely explanation. In chapter 3, I ran one of the more in depth and complicated tests for a relationship between paternal investment and realized paternity that I was able to find in the literature. I used the standard male feeding rate as a measure of male investment as well as a far more nuanced measure derived from the first Eigenvector of an analysis of six different paternal behaviors. These were both tested using Akaike's Information Criterion against a number of variables likely to affect parental behavior, including realized paternity. Ultimately, I found no evidence that kingbirds were able to affect paternal investment in response to lost paternity, and conclude that they likely had no means to assess realized paternity within the nest of their social mate. However, from the other parameters tested I was able to find that males increased their investment as brood size increased and as the female spent more time attending, but not feeding, the nestlings. Also, male investment decreased as territory density increased and flight feather length increased. Theory surrounding the variability of extrapair paternity in birds can be used to account for these results. In a denser population males are predicted to reduce paternal effort for one of two reasons: increased likelihood of paternity loss in his own nest and an increased investment in pursuing extrapair copulations of his own. Longer flight feathers are a sign of age and quality in kingbirds, so males with this trait are expected to spend more time pursuing extrapair copulations as they are more likely to be successful in this endeavor.

A substantial portion of the remaining coastal pine savanna in the southeastern U.S. is burned periodically to maintain habitat for the endangered Mississippi Sandhill Crane (Grus canadensis pulla). However, the effects of this burning on other species of birds are unknown. Therefore, a one-summer study was conducted to determine the short-term response of non-target bird species to changes in vegetation structure due to winter prescribed burning of coastal pine savanna. Eight 25-ha study plots were censused using the spot-mapping technique from May - July 1995 at the Mississippi Sandhill Crane National Wildlife Refuge. More species were observed on old burn sites (burned 1.5 - 3.5 yr prior to the study) than new burn sites (burned the previous winter). Gross vegetation features did not differ between treatments. A total of 17 breeding species were recorded during the study. Although there were no significant differences within individual species' densities, seven species were observed only on old burn sites. Winter prescribed burning affected the presence of only shrub-characteristic species. / Department of Biology

I studied selenium contamination at Cibola National Wildlife Refuge (Cibola NWR) in the lower Colorado River Valley, California and Arizona. My objectives were to: (1) determine whether local irrigation practices resulted in exposure of fish to toxic levels of selenium; (2) assess the risks to humans of consuming fish from Cibola NWR; (3) assess whether diversity and abundance of fish were related to selenium concentrations or other water quality variables. Water, sediment, fish, crayfish, and aquatic plants were collected from sites which received irrigation return flows and sites which did not. Selenium was below toxic levels at sites receiving irrigation return flows. Selenium was at the toxicity threshhold for fish at two sites receiving water directly from the Colorado River. Concentrations of selenium in fillets of largemouth bass (Micropterus salmoides) from one lake exceeded levels that elicit consumption advisories in California. Most people would be unlikely to consume toxic amounts of fish, but an advisory should be posted to inform people about potential risks. Gill nets were used to determine species diversity and abundance. There were no strong correlations between selenium levels and indices of species richness and equitability. There was a consistent inverse relationship between selenium levels and catch-per-unit-effort for all species combined. This inverse relationship suggested that selenium may be one of a suite of factors limiting abundance of fish. Correlations between indices of species diversity and abundance and values of water quality variables generally were not significant. Temperature and salinity may have limited abundance of some species seasonally. Increases in selenium levels at sites that are already at the toxicity threshhold could impair reproduction of sensitive species. Population declines and concern about edibility of fish could impair the recreational fishery. Therefore, site-specific ways to reduce selenium accumulation should be studied and implemented. Site-specific limnological conditions may play a role in accumulation of selenium to toxic levels, but major sources of selenium appear to be upstream in the Colorado River basin rather than local agricultural practices. Therefore, selenium input to the Colorado River from sources throughout the basin should be monitored and reduced where possible.

Shallow water availability coupled with anthropogenic degradation of seagrass beds limits wading bird food resources in dynamic coastal ecosystems. Identifying prey species critical to wading bird reproductive success and the environmental drivers of key prey species abundance is important for understanding how environmental stressors influence prey and change the quality of foraging patches. Little Blue Herons (Egretta caerulea) are reportedly generalists eating insects, crustaceans, and fish; however, the proportions of prey items in the diet may shift spatially and temporally from freshwater to marine systems during breeding and non-breeding periods. I investigated prey selection by Little Blue Herons in Florida at the Great White Heron National Wildlife Refuge and the western Florida Bay, during 2016 and 2017 breeding seasons by investigating prey availability at low-tide locations along mudflats compared to stomach regurgitate samples collected from Little Blue Heron chicks 1 to 4 weeks old. Little Blue Herons selected Gulf toadfish (Opsanus beta) and prawns (Farfantepenaeus spp.) from the estuarine environment, but also consumed terrestrial prey (e.g. tree crabs) suggesting Little Blue Heron foraging habitat is not restricted to tidal flats. Additionally, these results support the characterization of Little Blue Herons as a generalist. After identifying important prey species, I modeled the associations of selected prey species with submerged aquatic vegetation density and abiotic variables to better understand habitat preferences and important habitat characteristics that drive prey density. Models support total seagrass density and algal density as having the greatest effect on prey selected by Little Blue Herons. Prawn density has a strong positive association with seagrass density. Gulf toadfish (Opsanus beta) and prawns (Farfantepenaeus spp.) had strong positive association with algae while pipefish (Syngnathidae) had a strong negative association with algae suggesting algae density in seagrass meadows should be considered when assessing the quality of seagrass meadows for Little Blue Heron prey and habitat suitability. My results varied from previous studies where prawns and gulf toadfish were associated with specific seagrass species. Therefore, some Little Blue Heron prey species in south Florida may not be affected by changes in submerged aquatic vegetation community composition if submerged aquatic vegetation densities remain constant. Studies are needed that clarify the complex interactions between prey and specific habitat metrics to validate the strength of landscape scale drivers of wading bird prey densities in dynamic coastal ecosystems and to determine how these communities will respond to anthropogenic environmental change. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

A declining population of ring-necked pheasants (Phasianus colchicus) was studied at Tule Lake National Wildlife Refuge (TLNWR) from the summer of 1990 through the spring of 1993. Pheasant densities/50 ha at TLNWR in 1989, 1991, and 1992 were considerably lower (16.86, 8.49, and 6.81) than the >62 density seen in the mid-1950s. Mean body weight of hen pheasants at TLNWR was significantly lower than hens at nearby Lower Klamath National Wildlife Refuge (LKNWR) which was not intensively farmed. Mean tarsal lengths of hens at TLNWR were also significantly shorter than hens at LKNWR, suggesting reduced skeletal growth and potential nutritional problems. The lack of adequate cover was responsible for poor early nest success at TLNWR. Later in the season, spring planted crops provided adequate cover to conceal nesting hens; however, only 0.21 young in 1991 and 0.02 young in 1992 were produced per radio-equipped hen. These rates are extremely low compared to rates required to maintain a stable population. Most adult mortality occurred during the spring and early summer months at TLNWR before crops provided adequate cover, and long before pesticide applications. The main predator of the pheasants was the golden eagle (Aquila chrvsaetos). Of special concern at TLNWR was pheasant and other wildlife exposure to anticholinesterase (antiChE) insecticides used on agricultural croplands at the refuge. Direct toxicity of antiChE compounds (in this case methamidophos) killed 2 young pheasants, but no adult radio-equipped hens died as a direct result of insecticide intoxication. This finding was of particular interest because 15% of the adult pheasants collected in and around potato fields had 55% brain ChE inhibition. The extent of the effects of insecticide exposure on the survivorship of pheasant young was uncertain as they were not radio-equipped. The overriding factor impacting the pheasant population at TLNWR and to a lesser extent LKNWR was poor habitat, especially in the spring when most mortality occurred. The poor habitat also resulted in extremely low recruitment (up to 1 September). Nearly all adult mortality and most of the low recruitment occurred before the insecticide spray season. The population was nearly extirpated during the severe winter of 1992-93. / Graduation date: 1995

The Lower Rio Grande Valley (LRGV) of Texas is an ecologically diverse region in the United States and marks the northernmost extension for many tropical species of plants and animals. Since the early 1900s, 95% of the native Tamaulipan brushlands have been cleared due to agricultural practices and urban development. The plain chachalaca (Ortalis vetula) is a medium sized bird endemic to the native brushlands of the LRGV. In 2003, I trapped and radio-tagged 29 birds (16 males, 13 females) to evaluate the effects of fragmentation on the population dynamics (i.e., survival, mortality, and movements) of this brushland species. My study objectives were to estimate (1) seasonal survival of chachalacas by sex, and (2) ranges, core areas, and movements using radio telemetry. Mammalian predation (43%, n = 6) and unknown (43%, n = 6) deaths accounted for the majority of mortality observed. I found no difference (P > 0.05) in estimated 8-month survival (December 2003-July 2004) between males (S = 0.364, SE = 0.132) and females (S = 0.405, SE = 0.153). In comparing seasonal survival for all birds (males and females combined), I observed a difference (P < 0.05) in survival between the nesting (S = 0.414, SE = 0.103) and breeding seasons (S = 0.917, SE = 0.079). Female ranges (x‾ = 117 ha, range = 42–177 ha) and core areas (x‾ = 23 ha, range = 5–46 ha) during the nesting season were larger than male ranges (x‾ = 41 ha, range = 31–46 ha) and core areas (x‾ =10 ha, range = 7–14 ha) during the same period. During the breeding season, female ranges (x‾ = 59 ha, range = 10–188 ha) and core areas (x‾ = 9 ha, range = 2–33 ha) were similar to male ranges (x‾ = 48 ha, range = 4–130 ha) and core areas (x‾ = 9 ha, range = 1–23 ha). Mean distances between seasons were similar for both sexes (females, nesting, x‾ = 486, breeding, x‾ = 345; males, nesting, x‾ = 184, breeding, x‾ = 292), though females distances generally were greater. Dispersal defined as movement off the Santa Ana National Wildlife Refuge was observed for 3 birds. In 2 cases, a radio-tagged female and male were observed crossing the Rio Grande River (approximately 100-m wide) to habitat in Mexico. Study results suggested mammalian predation may limit the growth of chachalaca populations. Though land use changes such as agricultural uses may not directly limit chachalaca populations in providing cover and food, concentration of populations in remnant native brushlands may serve as ecological “sinks” to the species. Greater range and movement data observed in my study may be attributed to suboptimal habitat (i.e., increased fragmentation) for plain chachalacas.

Understanding the salt marsh ecosystem in the Guadalupe Estuary is needed because wetlands in this system support the endangered whooping crane (Grus americana). The marsh plant research and monitoring described herein were based in the salt marshes at Aransas National Wildlife Refuge (ANWR), which are utilized by the cranes each winter. Past research indicates that the Carolina wolfberry (Lycium carolinianum) contributes 21-52% of crane energy intake early in the wintering period (Chavez 1996). Beginning in Fall 2003, vegetation transects were sampled along an estuarine gradient at ANWR. Species diversity and composition was similar at the three sites, with all sites containing the same 6-7 common species. While Spartina alterniflora is only a minor part of this vegetation community, it dominates the few low inter-tidal, fringe areas present. Species composition exhibited little variability from Year 1 to Year 2 of the study. Densities and biomass of L. carolinianum were not significantly different between sites or years. L. carolinianum, while important to salt marsh ecology, accounts for only a small portion of the overall productivity. Based on correlation coefficients, L. carolinianum was found in association with some of the common species in the vegetation community, indicating that its growth and survival requirements are typical to the salt marshes at ANWR. Also beginning in Fall 2003, I repeatedly sampled L. carolinianum in permanent plots along the estuarine gradient. L. carolinianum exhibits strong temporal patterns. Leaf production peaked in early spring and again just prior to peak berry abundance. Flowering of L. carolinianum occurred in October and November. Peak berry abundance coincided with the cranes’ arrival in late October and early November. Berry production occurred in October, November, and December; berries were virtually non-existent in the marshes for the remainder of the year. Stepwise regression showed stem diameter alone was a good estimator of aboveground biomass of this species in ANWR marshes, accounting for 94% of the variability (p<0.001). Changes in aboveground biomass followed no distinct patterns in the year of monitoring, perhaps due to the woody stem of the plant. Spatial patterns in L. carolinianum were not explained by water quality parameters alone; it is suggested that soil properties may help to account for the spatial variability.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 221-235). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 221-235). Also available on the Internet.

Thesis (Ph. D.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains vii, 125 p. : ill., map. Includes abstract. Includes bibliographical references (p. 90-96).