Ongoing Research Collaborations
Migratory Connectivity of Louisiana Waterthrush and Worm-eating Warbler
The Ruhl lab is currently part of a research collaboration with ornithologists from University of Tennessee, Tennessee River Gorge Trust, and University of Toledo working to investigate the migration ecology and range-wide migratory connectivity of Louisiana Waterthrush and Worm-eating Warbler. Stay tuned for the exciting results from this project!
Check out the Gallery to view photos from this project!
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Research collaborators:
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University of Tennessee, Knoxville
Dr. David A. Buehler
Elliot Berz (Graduate Student)
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Tennessee River Gorge Trust
Rick Huffines​​
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University of Toledo
Dr. Henry M. Streby
Silas Fischer (Graduate Student)
Gunnar Kramer (Graduate Student)
Annie Crary (Graduate Student)
Range-wide Genetic Variation of Prairie Warblers
The Ruhl lab is also participating in a research collaboration with ornithologists from University of New Hampshire and Antioch University to investigate the population genetics and gene flow of Prairie Warblers across their breeding range in the U.S. Prairie Warblers are somewhat rare in the state of Arkansas, but in certain locations managed for early successional habitat this species can be quite abundant.
Undergraduate Research Projects at HU
Elisa González Dalton Kidder Fallon Hale Mason Adams
Lucy Floyd Amanda McNeill Rebecca Stephens Abby Howell
Non-breeding ecology of North American sparrow species is an important research focus of full annual cycle conservation for these "short-distance" migrants. Thanks to decades of observational studies, we have a pretty solid understanding of diurnal habitat use and foraging preferences for most species, but roosting ecology and habitat selection remains an elusive knowledge gap. During January and February, my students use radiotelemetry methods to determine roosting habitat preferences of overwintering White-throated sparrows at Harding University's Gilliam Biological Research Station, in Arkansas. Results from 2023 field season have been published in the Wilson Journal of Ornithology. Stay tuned for the results from this year's study!
Karena Barlow Hannah Adams Aric McKinney
Optimal foraging theory predicts that organisms should make foraging decisions that maximize net energetic gain. In 2020 and 2021, Karena, Hannah, and Aric used radio frequency identification (RFID) technology to determine whether the foraging preferences of Tufted Titmice (Baeolophus bicolor) matched the predictions of optimal foraging models in situ. We tested two prey items (whole sunflower seeds and sunflower kernels) to assess the predictions of optimal foraging cost-benefit models in an experiment in which the energetic currency of food was kept constant, but handling time differed. Our results from this study were published in 2023!
Fallon Hale and Michaela Hutcheson
You are what you eat! That old adage is actually quite true, and students in the Ruhl lab are currently using stable isotopes to characterize the diet of wintering sparrows at the Gilliam Biological Research Station. There are several species of sparrows that call GBRS home during the winter months, and we are investigating the importance of isotopically distinct diet items for wintering sparrows in the context of anthropogenic food supplementation (e.g., bird feeders). To assess these questions, Harding undergraduate students, Fallon Hale and Michaela Hutcheson, are collecting blood samples from White-throated Sparrows (Zonotrichia albicollis), Song Sparrows (Melospiza melodia), and Dark-eyed Juncos (Junco hyemalis) to assess diet similarities and niche partitioning of sympatric species.
Graduate Research at Purdue University
Ph.D.
I did my Ph.D. research in the Dunning Lab of the Forestry and Natural Resources Department at Purdue University. During the summer (May 31-Aug 15), I mist-netted and banded birds in the clearcuts of the Hardwood Ecosystem Experiment (HEE). The HEE is a 100-year landscape-level study monitoring the social and ecological impacts of forest management within the Morgan-Monroe and Yellowwood State Forests in southern Indiana. My project focused specifically on the association of mature forest birds with early successional habitat during the postfledging period. Neotropical migrants that require large tracts of mature forest for breeding and nesting, such as Worm-eating Warbler, Ovenbird, Wood Thrush, and Scarlet Tanager often move into early successional habitat during the postfledging period (the time between nesting and migration). Although there are several hypotheses to explain this behavior, the driving factors behind species-specific habitat association during this time remain largely unknown. I used a variety of techniques (e.g., constant-effort mist-netting, stable isotope analysis, and radiotelemetry) to address these habitat use questions.
M.S.
I was fortunate enough to complete my Masters research in the Purdue University Forestry and Natural Resources Department in 2014. My research focused on the effects of intensive biomass harvest for bioenergy on eastern red-backed salamanders in Jennings county, Indiana. Plethodontids have been suggested as an ideal bio-indicator species for forest ecosystems. Because they are considered to be a surrogate for forest ecosystem health, I monitored the abundance of Eastern red-backed salamanders in response to a gradient of 0-100% retained coarse woody debris (CWD) following timber and biomass harvesting. I also considered key aspects of salamander health such as standard metabolic rate and body condition. CWD was a significant predictor of salamander abundance. However, I was not able to identify a threshold of resilience for plethodontids based on the gradient of retained CWD. This study emphasizes the need for future wildlife research on biomass harvesting to ensure appropriate implementation of regulations that provide better protection of the integrity and biodiversity in forest ecosystems.
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