Gwen C. Bachman
Gwen Bachman
Associate Professor

Ph.D. University of California-Los Angeles, 1992
B.A. University of California-San Diego, 1983
         (Ecology, Evolution & Behavior)
Contact Information
231 Manter Hall


Research Interests

Research in our lab examines various dimensions of animal energetics with an emphasis on the influence of energetics on reproductive trade-offs.  Energy flow through organisms has long been recognized as a central process underlying ecological interactions and evolutionary adaptation.  The rate and amount of net energy acquisition and storage are clearly linked to production, therefore it is reasonable to propose energetic 'costs' and physiological limits as selective forces affecting the expression of reproductive strategies. Currently, my students and I are focusing on questions in the following general areas: stress physiology and endocrinology, eco-immunology, metabolic physiology, microhabitat choice, and reproductive success in birds (sharp-tail grouse and passerines), and reptiles (box turtle).  We are completing a project which examines corticosterone and stress responses in grouse during the lekking period. Ongoing work uses a marked population of ornate box turtle,  Terrapene ornata,  at UNL’s Cedar Point Biological Station. Our interest in the turtles is based on their ability to survive extended periods of low resource availability, and an ability to delay reproduction until conditions improve. Species with these life history characteristics may be particularly challenged by climate change, or, through behavioral or physiological compensation, they may be able to adapt within their lifetime. To better understand the impact of long-term climate change on box turtle populations, we are collecting data to describe relationships between temperature, behavior, physiology, and reproductive output. Key physiological variables that are currently being examined are: metabolic rates associated with resting and activity at different temperatures, body condition,  indicators of stress (testosterone, corticosterone), blood chemistry, and immune function. We are fundamentally field biologists, so the physiology is always framed by behavioral observations and ranging behavior through radio-telemetry. These data together with habitat variables will become part of a model that predicts the impact of warming on energy requirements, survival and reproduction in this species.  

** Graduate student(s) wanted !!  Dr. Gwen Bachman and Dr. Joseph Fontaine are seeking to co-sponsor a PhD student to examine the impact of climate on bobwhite quail populations. This work will also be conducted with Dr. Jeffery Lusk, of  the Nebraska Game and Parks Upland Game Program.  We will be working with birds in the northern part of the species range, thus cold temperature effects are the focus of the study.  The ultimate goal is to inform management practices, but we will be taking the unique approach of examining how climatic constraints are manifested through physiological state, and how this may influence population dynamics. There will be two components to the study. The first is a telemetry field study in which we examine basic habitat needs by following individuals in various study plots maintained by Nebraska Game and Parks. Through this roost sites in different habitat types and under different weather conditions, including winter, will be identified. The second major component of the study will examine the physiology of captives subjected to different temperature regimens. We will be analyzing blood samples for indicators of stress, body condition, and will be measuring metabolic rates.  The diversity of skills and interests will require a special candidate. Ideally, you will have a solid background in biology including physiology, and research experience that includes field work. This is an ideal opportunity for someone interested in exploring an interface between management or conservation, and physiology.   

Candidates can reside either primarily in the School of Natural Resources with Dr. Fontaine (, or in the School of Biological Sciences ( with Dr. Bachman. Please feel free to contact me ( if you have questions. 

Recent Publications

  • Bachman GC. 2000. Changes in leukocyte counts in hibernators from spring through summer. AMERICAN ZOOLOGIST 40 (6): 933-933.
  • Bachman, G., F. Widemo. 1999. Relationships between body composition, body size, and alternative reproductive tactics in a lekking sandpiper, the Ruff (Philomachus pugnax). Functional Ecology: 13:411-416.
  • Bachman, G.C., Chappell, M.A. 1998. Energetic cost of begging in house wrens (Troglodytes aedon). Animal Behaviour 55:1607-1618.
  • Chappell MA, Bachman GC.1998. Exercise capacity of House Wren nestlings: Begging chicks are not working as hard as they can. AUK 115 (4): 863-870.
  • Chappell, M. A., Bachman, G. C. and Hammond, K. A.1997. The heat increment of feeding in house wren chicks: Magnitude, duration, and substitution for thermostatic costs. Journal of Comparative Physiology B 167: 313-318.
  • Bachman, G.C. and S.L. Vehrencamp. 1995. "Ecological Energetics of Terrestrial Vertebrates" , p. 549-565 in "Encyclopedia of Environmental Biology", Academic Press.
  • Bachman, G.C. 1994. Food restriction effects on the body composition of free-living ground squirrels. Physiological Zoology 67:756-770.
  • Bachman, G.C. 1993. The effect of body condition on the trade-off between vigilance and foraging in Belding's ground squirrels. Animal Behaviour 46:233-244.