About This Project
Will hummingbirds tolerate high temperatures due to climate change? Many studies look at heat tolerance during rest, but we study heat tolerance during hovering. Hummingbirds produce extra heat while hovering that must be dissipated to prevent overheating. Our previous work shows that in warm temperatures hovering hummingbirds cannot cool themselves. In this study we explore whether or not hummingbirds select perches in cool places between hovering bouts to facilitate heat loss.
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What is the context of this research?
Hovering is critical to a hummingbird's ability to fulfill their ecological role as pollinators. However, hummingbird hovering could become limited by climate change. Low mechanical efficiency of flight muscles results in extra heat production which cannot be dissipated at warm temperatures due to loss of a thermal gradient. Further, heat dissipation while hovering in warm temperatures does not appear to promote increased evaporative heat dissipation. Many animals compensate for the inability to physiologically dissipate heat with behavioral thermoregulation. We will test if hummingbirds behaviorally thermoregulate by using perches in microclimates that promote heat loss between hovering bouts.
What is the significance of this project?
Everyone enjoys watching hummingbirds, but increases in both mean and extreme temperatures predicted for our changing climate could make it difficult for them to exist in current habitats. For reasons mentioned above in project context warm temperatures could prevent hummingbirds from flying/hovering for extended periods which would not only hinder their ability to provide important pollination services, but restrict their ability to engage in important activities like courtship behavior which is critical to reproduction. Understanding the extent to which warming temperatures could alter hummingbird behavior will not only help us to anticipate potential community and ecosystem impact, but also inform management strategies that could minimize climate effects.
What are the goals of the project?
Because hummingbirds do not appear able to physiologically dissipate the all extra heat produced while hovering in warm temperatures we propose to test whether or not they use a type of behavioral thermoregulation between hovering bouts to rid themselves of heat accumulated during hovering bouts.
We plan to conduct a laboratory study using an artificially cooled perch to see if hummingbirds select a cool microclimate to dissipate heat following hovering at warm temperatures.
We also plan to conduct a field study to characterize microclimates of perches used by hummingbirds after hovering bouts throughout the day and over a range of temperatures.
We predict that hummingbirds will intentionally perch in cool microclimates following hovering to facilitate heat loss.
We will rent a full-size pickup (e.g. Ford F150) to transport our equipment and supplies from Oregon to Arizona. In the long run we have found that transporting our equipment and supplies in this manner is safer and frankly cheaper than shipping due to the sensitivity of our electronics, and size, shape, and weight of all that we need to do the work. We also need a rugged vehicle for travel in the Chiricahua Mts between study locations so we kill two birds with one stone.
This project involving two talented undergraduate researchers began this Spring with design of the protocol and review of the key literature supporting the project. Data collection and most analysis will occur between May-August 2019, and wrap up with project presentations at two meetings in Fall/Winter. Specific project milestones are listed below.
May 08, 2019
May 17, 2019
Complete construction and testing of all equipment used in the project.
Jun 05, 2019
Travel to the Southwestern Research Station in SE Arizona to collect data.
Jun 24, 2019
Return to George Fox University to begin data analysis.
Nov 08, 2019
Present project data at the Murdock Charitable Trust Collaborative Undergraduate Research Meeting (Vancouver, WA).
Meet the Team
Donald R Powers
I am a Professor of Biology at George Fox University, and have studied various aspects of hummingbird physiology/ecology/biomechanics for nearly 40 years. My work on the energetics and biomechanics of hummingbird hovering, published in Nature in 2005, revealed important insights into the mechanics and evolution of this key hummingbird adaptation. In addition I have published numerous works that have added to our understanding of hummingbird energy management, flight metabolism, water regulation, evaporative water loss, and torpor. I am currently wrapping up a NASA-funded study of hummingbirds in both Arizona and Ecuador in which I explored how they will physiologically respond to increases in global temperature resulting from climate change. I received my B.S. degree in biology from Biola University, an M.S. in ecology from San Diego State University (advisor: Dr. George Cox), and a Ph.D. in physiological ecology from the University of California, Davis (Advisor: Dr. Wesley Weathers).
I am an undergraduate student at George Fox University pursuing a BS degree in Biology with a minor in Mathematics. My previous research experience includes work in the Piovia-Scott lab at WSUV studying amphibian disease ecology in northern California. Currently, I am interested in behavioral adaptations of hummingbirds in response to increased environmental temperatures in the Powers Research Lab. The opportunity to conduct research in the Powers Research Lab is incredibly important for my development as a scientist, and I am excited for the hard work and rewarding experiences that are to come. In graduate school, I plan to pursue a PhD in a field such as computational biology or systems biology, which will apply my skills in mathematics to solve biological problems.
I am a Junior Biology major at George Fox University. This will be my first experience working full-time in research and I am excited for the opportunity. I will be studying the use of perching microclimates by hummingbirds in warm ambient temperatures at the Southwestern Research Station in the Chiricahua Mountains of southeastern Arizona. I am excited to be part of the Powers Lab because it will be a critical part of my preparation for graduate school. Once finished with my BS degree I plan to pursue a Ph.D. in ecology or related field, and oversee my own research program.
Mission of the Powers Lab
Since George Fox University has no graduate program in biology undergraduate students play a key role in lab productivity. Peer-reviewed publications resulting from work done by research teams in the lab often include undergraduate coauthors who make important contributions to both data collection and analysis. The mission in involving undergraduates in the lab research program is to provide a quality experience that prepares them to be competitive for and successful in top-level graduate or professional programs once they finish their degree. Students who take positions in the lab must take ownership for their entire projects rather than specific experiments assuring that they will gain valuable experience in all facets of basic research. This includes presentation of their work at the Society for Integrative and Comparative Biology (SICB) national meeting each January. Elliot and Nathaniel, the lead investigators on this proposed project, will gain invaluable experience in preparation for their post-graduate pursuits should this proposal for a portion of the required funding be successful. Below are some SICB presentations made by students funded via this platform the past two years.
Our Study Site
Most of our data will be collected at the Southwestern Research Station (SWRS) which is located on the east slope of the Chiricahua Mountains in the far southeastern corner of Arizona. SWRS is an ideal place for our work because it supports healthy populations of three hummingbird species (see below) that exhibit three distinct foraging strategies potentially offering potential variation in how body temperature is managed during hovering. Also, the environment around SWRS is thermally complex making it ideal for studies of microhabitat selection. Because SWRS has good laboratory facilities all our planned experiments can be supported.
Our Study Species
Are three study species will be the blue-throated hummingbird (Lampornis clemenciae, ~8.3 g), the Rivoli’s hummingbird (Eugenes fulgens,~7.5 g), and the black-chinned hummingbird (Archilochus alexandri, ~3.6 g). The blue-throated hummingbird is a territorial species and is the most dominant hummingbird at SWRS.
Rivoli's hummingbird is a trap-liner species that forages over a large area around the SWRS site.
The black-chinned hummingbirds is the smallest of our study species and is subordinate to the blue-throated hummingbird. To forage the black-chinned hummingbird must intrude on flowers and feeders defended by blue-throated hummingbirds.
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