Ornithology Commons^™

Swainson's Thrushes Do Not Show Strong Wing Selectivity Prior To Crossing The Gulf Of Mexico, Rachel T. Bolus, Robert H. Diehl, Frank R. Moore, Jill L. Deppe, Michael P. Ward, Jaclyn Smolinsky, Theodore J. Zenzal Jr.

Faculty Publications

During long-distance fall migrations, nocturnally migrating Swainson’s Thrushes often stop on the northern Gulf of Mexico coast before flying across the Gulf. To minimize energetic costs, trans-Gulf migrants should stop over when they encounter crosswinds or headwinds, and depart with supportive tailwinds. However, time constrained migrants should be less selective, balancing costs of headwinds with benefits of continuing their migrations. To test the hypotheses that birds select supportive winds and that selectivity is mediated by seasonal time constraints, we examined whether local winds affected Swainson’s Thrushes’ arrival and departure at Ft. Morgan, Alabama, USA at annual, seasonal, and nightly time …

Effects Of Human Disturbance On Physiology, Behavior, And Ornamentation In The Eastern Bluebird, Lauren Marjorie Gillespie

Dissertations

Overall, few studies have focused on anthropogenic disturbance on wildlife physiology. Research has typically focused on how environmentally contaminated areas or anthropogenic disturbance (e.g. noise, human activity) influences biodiversity, community structure and behavior of individual animals. However, understanding how disturbance influences some aspects of physiology can require sacrifice of the animal, prohibiting ecologically relevant measures of behavior and reproductive success. This research strives to examine covariation between testosterone (T) and corticosterone (CORT), plumage ornamentation, and behavior in two populations of eastern bluebirds (Sialia sialis) that differ in degree to which their habitat is modified by human activity.

In …

Stopover Ecology Of Ruby-Throated Hummingbirds (Archilochus Colubris) During Autumn Migration, Theodore Joseph Zenzal Jr

Dissertations

The Ruby-throated Hummingbird (Archilochus colubris) is one of the smallest Nearctic-Neotropical migrants and the only species of hummingbird that breeds in Eastern North America, yet few studies have investigated the biology of Ruby-throated Hummingbirds when they stopover during migration. Given their small size, high metabolism, aggression, and specialized diet, hummingbirds may represent a migrant that operates on the physiological edge. Therefore it is important to understand the factors that influence their stopover as well as the decision to resume migration. Towards this end, Ruby-throated Hummingbirds were captured during autumn migration along the northern coast of the Gulf of Mexico to …

Territorial Defense Strategies In The Northern Cardinal (Cardinalis Cardinalis): Who Is The Bigger Threat?, Kaylee M. Gentry

Master's Theses

This thesis examines the use of defensive strategies in relation to territories year round in the northern cardinal (Cardinalis cardinalis). Responses to recorded neighbor song and stranger song playback from the middle of a focal male’s territory were measured. This allowed for an estimation of aggression in both the winter and spring seasons. Each focal male was subjected to both treatments (stranger song and neighbor song). Males were more responsive over-all to neighbor song playback, however in the winter months, persistence of response to neighbor song playback increased. It was also shown that southeastern United States cardinals show …

Gut Microbiota Of Migratory Passerines At Stopover, William Bagley Lewis

Master's Theses

Although the gut microbiota provides many beneficial functions to animal hosts, relatively little is known about the gut microbiota of passerines. It is likely that gut microbes are especially important during the migratory phase; however gut atrophy experienced during prolonged migratory flight may cause disruptions of the stable microbiota. Fecal samples were collected from several species of passerine after crossing the Gulf of Mexico during spring migration and before crossing during fall, and microbiota communities were analyzed using next-generation sequencing. Despite showing large inter-individual variation, a core microbiota composed largely of Firmicutes and Proteobacteria was identified in all birds. Microbiota …

Competition And Habitat Quality Influence Age And Sex Distribution In Wintering Rusty Blackbirds, Claudia Mettke-Hofmann, Paul B. Hamel, Gerhard Hoffman, Theodore J. Zenzal Jr., Anne Pellegrini, Jennifer Malpass, Megan Garfinkel, Nathan Schiff, Russell Greenberg

Faculty Publications

Bird habitat quality is often inferred from species abundance measures during the breeding and non-breeding season and used for conservation management decisions. However, during the non-breeding season age and sex classes often occupy different habitats which suggest a need for more habitat-specific data. Rusty Blackbird (Euphagus carolinus) is a forested wetland specialist wintering in bottomland hardwood forests in the south-eastern U. S. and belongs to the most steeply declining songbirds in the U.S. Little information is available to support priority birds such as the Rusty Blackbird wintering in this threatened habitat. We assessed age and sex distribution and …

Seasonal Variation In Corticosterone, Stress Responses, And Physiology In The Northern Cardinal Cardinalis Cardinalis, Benjamin Matthew Duckworth

Master's Theses

Seasonal regulation of the adrenocortical response (e.g., ‘stress response’) appears to be ubiquitous in mid- to high-latitude vertebrates. Northern Cardinals (Cardinalis cardinalis) are a Temperate dwelling passerine of Tropical-descent with a wide species range (tropics to Northern Temperate zones). This species encounters a wide variety of environmental conditions and strong seasonality, however corticosterone (CORT, the main adrenal stress hormone) has not been studied with regards to changes in seasonal levels. I initially analyzed samples from cardinals collected between 2007-2011 from the Lake Thoreau Environmental Research and Educational Center (Hattiesburg, Mississippi, USA). The data suggested seasonal differences of CORT, with higher …

Investigating The Function Of The Mold Specific Gene M46, In The Pathogenic Dimorphic Fungus Histoplasma Capsulatum, Davida Lashaundra Crossley

Dissertations

Histoplasma capsulatum (Hc) is a dimorphic fungus that is the etiologic agent for the respiratory infection histoplasmosis. The fungus is found in the environment in contaminated soils of birds and bat excreta as a multi-cellular saprophytic mold. Once the soil is disturbed, spores are released and are inhaled into the lungs. In the lungs, the fungus converts to uni-cellular parasitic yeast (Maresca & Kobayashi, 1989). The conversion from mold to yeast is a requirement for pathogenesis. Previously, several mold specific genes have been isolated by our laboratory from a subtracted cDNA library. One such gene, is M46. M46 is a …

Interrelationships Between Testosterone, Aggression, And Parental Care Of A Temperate-Zone, Resident Songbird, The Northern Cardinal (Cardinalis Cardinalis), Margaret Susan Devries

Dissertations

Interrelationships among testosterone (T), aggression, and parental care have received much investigative attention. Within birds, many studies have focused on examining such relationships using species characterized by relatively brief periods of territoriality and breeding. Few have investigated links between circulating T and reproductive behavior in birds that are year-round territorial residents and have lengthy breeding seasons, such as the Northern Cardinal (Cardinalis cardinalis). The following six chapters report and discuss findings from this dissertation’s examination of aspects of T production and potential interconnections with circulating T, aggression, and parental care in male and female cardinals. This work suggests …

A Bird In The Binoculars: Understanding Birdwatchers' Potential To Contribute To Sustainable Development And Biological Conservation, Sheri Lynn Glowinski

Dissertations

The three studies comprising this research drew from local economic development and environmental sociology to understand aspects of human dynamics that influence the conservation of birds. Using survey data collected from birdwatchers visiting coastal Alabama, the first study examined the local economic impact of birdwatching tourism and the factors that participants deemed important with respect to their recreation. Birdwatchers spent $103,305 during the four month study period. The total annual economic impact of this recreation on the area was estimated at $937,470, producing a multiplier of 1.48 and the equivalent of 20.3 full time jobs. Infrastructural variables (parking, bathrooms, site …

Experimental Evidence For The Interplay Of Exogenous And Endogenous Factors On The Movement Ecology Of A Migrating Songbird, Emily B. Cohen, Frank R. Moore, Richard A. Fischer

Faculty Publications

Movement patterns during songbird migration remain poorly understood despite their expected fitness consequences in terms of survival, energetic condition and timing of migration that will carry over to subsequent phases of the annual cycle. We took an experimental approach to test hypotheses regarding the influence of habitat, energetic condition, time of season and sex on the hour-by-hour, local movement decisions of a songbird during spring stopover. To simulate arrival of nocturnal migrants at unfamiliar stopover sites, we translocated and continuously tracked migratory red-eyed vireos (Vireo olivaceus) throughout spring stopover with and without energetic reserves that were released in two replicates …

Tick Infestations And Their Consequences For Migratory Songbirds During Spring Stopover, Johnny Michael Sellers Jr.

Master's Theses

Migratory birds face a number of challenges during their seasonal movement from tropical/sub-tropical Central and South America to more temperate North America. Maintaining health during migration is of particular concern. This study seeks to understand how haematophageous ectoparasites, such as ticks (Ixodida), impact host body condition as they feed on passerines during migration. We hypothesized that foraging location would impact tick acquisition by migrants and that tick burdens during migration would negatively impact body condition. We surveyed 2,064 birds during spring 2009 and 2010 and found that 2.4% of the surveyed birds were infested with one or more …

Ornamentation, Behavior, And Maternal Effects In The Female Northern Cardinal, Caitlin Winters

Master's Theses

This study seeks to understand the relationship between ornamentation, maternal effects, and behavior in the female Northern Cardinal (Cardinalis cardinalis). Female birds possess ornaments that indicate a number of important known aspects of quality and are usually costly to maintain. However, the extent to which female specific traits, such as maternal effects, are indicated is less clear. It is predicted by the Good Parent Hypothesis that this information should be displayed through intraspecific signal communication. Specifically, androgens and carotenoids are of interest in this study because both are linked to ornamentation, and are also important egg components that …

Integrating Concepts And Technologies To Advance The Study Of Bird Migration, W. Douglas Robinson, Melissa Bowlin, Isabelle Bisson, Judy Shamoun-Barnes, Kasper Thorup, Robert H. Diehl, Thomas H. Kunz, Sarah Mabey, David W. Winkler

Faculty Publications

Recent technological innovation has opened new avenues in migration research - for instance, by allowing individual migratory animals to be followed over great distances and long periods of time, as well as by recording physiological information. Here, we focus on how technology - specifically applied to bird migration - has advanced our knowledge of migratory connectivity, and the behavior, demography, ecology, and physiology of migrants. Anticipating the invention of new and smaller tracking devices, in addition to the ways that technologies may be combined to measure and record the behavior of migratory animals, we also summarize major conceptual questions that …

Information Acquisition And Sociality Among Migratory Birds, Zoltán Németh

Dissertations

Information use is a key feature of adaptive behavior: the better informed an individual, the better it is able to adjust its behavior to meet the demands of a variable world. Therefore, most animals attempt to reduce environmental uncertainty by gathering information when it is available. However, tracking unpredictable ecological factors may carry costs as individuals invest valuable time and energy in the process of information acquisition. Social learning (i.e., use of social information inadvertently produced by other individuals) enables the individual to gain rapid and more complete assessment of its novel environment. This process may be particularly important for …

Natural Selection On Testosterone Production In A Wild Songbird Population, Joel W. Mcglothlin, Danielle J. Whittaker, Sara E. Schrock, Nicole M. Gerlach, Jodie M. Jawor, Eric A. Snajdr, Ellen D. Ketterson

Faculty Publications

Because of their role in mediating life-history trade-offs, hormones are expected to be strongly associated with components of fitness; however, few studies have examined how natural selection acts on hormonal variation in the wild. In a songbird, the dark-eyed junco (Junco hyemalis), field experiments have shown that exogenous testosterone alters individuals' resolution of the survival-reproduction trade-off, enhancing reproduction at the expense of survival. Here we used standardized injections of gonadotropin-releasing hormone (GnRH) to assay variation in the testosterone production of males. Using measurements of annual survival and reproduction, we found evidence of strong natural selection acting on GnRH-induced …