Powers Lab Studies Keel Bone Damage in Laying Hens

The Powers Lab began work on a study of keel bone damage in laying hens in collaboration with a research group headed by Dr. Alexandra Harlander at Guelph University. The research group will also involve long time collaborator Bret Tobalske at the University of Montana. The core goal of the project will be to understand what aspects of communal housing lead to injury and mortality rates higher than for caged hens. Of specific interest will be damage to the keel bone, especially fractures, that are known to be quite painful. Susceptibility to skeletal injury is like a consequence of selection for high egg project. The increasing demand for cage-free eggs by consumers has heightened the need to understand the best ways to provide enriched environments for hens that minimize risk of injury.

The Powers Lab will oversee experiments designed to assess the energetic cost of keel bone injury to the hens. This will include measurement of both resting and active metabolic rates, including metabolic rate during short-term flights. We will also measure daily energy expenditure using doubly labeled water. Our work on the project officially started on December 11 when Don traveled to the University of Montana to train Dr. Neila Ben Sassi, a postdoc on the project, and graduate student Renee Garant on open-flow respirometry and blood sample collection for doubly labeled water. While in Montana we used rock pigeons for the training sessions since Bret had already trained them to wear the respirometry mask needed for some measurements.

From left to right Neila, Don, Bret, and Renee!! The whole gang in the Flight Lab!
Rock pigeon wearing a respiratory mask for demonstration of using open-flow respirometry to measure the metabolic cost of short flights.

Once things get into full swing Don and possible one of the undergraduate researchers will likely make a trip to Guelph mid-summer to help with the work.








Powers Lab Travels to SICB

This week the Powers Lab travel to Austin, TX for the Society for Integrative and Comparative Biology (SICB) meeting. Undergraduate researches Elliot Shannon and Nathaniel Shiiki presented posters on the work they did in Arizona this past Summer, while lab PI Don Powers gave a talk on his most recent work on heat dissipation during hovering in calliope hummingbirds done in collaboration with Dr. Bret Tobalske’s lab at the University of Montana. Once again both Elliot and Nathaniel did amazing jobs with their presentations receiving praise from many who attended their poster sessions.

Elliot ready to present his poster at SICB!
Nathaniel ready to present his poster at SICB!
Don giving his talk at SICB!

This year’s SICB meeting was particular rewarding as we got to spend time with former undergraduate researchers in the Powers Lab Sean Powers (yes, Don’s F1) and Keely Corder. Sean is currently a Ph.D. student at Virginia Commonwealth University in Richmond, VA and Keely is a Ph.D. student at the University of Montana.

Sean Powers presenting his research on gypsy moths at SICB!

It was also great to reconnect with many friends and colleagues from across the world. It was good to spend time Dave Swanson (University of South Dakota, and GFU alumnus), Todd McWhorter (University of Adelaide), Anusha Shankar (University of Alaska), Hugh Ellis (University of San Diego), Ken Welch (University of Toronto), Blair Wolf (University of New Mexico), Bob Mason (Oregon State University), Chris Clark (University of California, Berkeley), Kimberly Sheldon (University of Tennessee), and many others. It was also fun to meet and chat with several graduate students who expressed interest in the work we do in the Powers Lab. All in all the meeting was a very productive time both professionally and personally.

Sean Powers presenting at SICB

Powers Lab crew at SICB

Opening plenary session at SICB

Nathaniel prenting to Dr. Jon Harrison from Arizona State University

Dr. Sheila Patek, Duke University, giving the plenary at SICB

Elliot working his poster at SICB

Don wrapping up his talk at SICB

Undergraduate Researchers Present at the 2019 Murdock College Science Research Conference

This month all three of the undergraduate researchers in the Powers lab presented data at the Murdock College Science Research Conference in Vancouver, WA. This is a meeting that is focused on undergraduates, and the sole goal is to promote serious science research at small institutions like George Fox University. Further, the students receive input and encouragement from faculty who teach at institutions throughout the Northwest. I think that the MJ Murdock Charitable Trust, and program direction Dr. Moses Lee, do an amazing job with this conference.

Nathaniel Shiiki and Elliot Shannon presented the results of the work they did in Arizona this past summer. Presenting at the Murdock Conference is a great tuneup for the Society for Integrative and Comparative Biology meeting that wee will attend in a couple months.

Elliot Shannon presenting his poster at the Murdock conference!
Nathaniel Shiiki presenting his poster at the Murdock conference.

Also presenting was Tiffany Regier who presented data I collected in collaboration with Dr. Bret Tobalske and his Ph.D. student Tony Lapsansky last May. This was a great opportunity for Tiffany to gain presentation experience as she gears up to write her own research proposal in the Spring.

Tiffany Regier presenting her poster at the Murdock conference.

Powers Lab group photo!

George Fox University crew at the Murdock Conference banquet.

Nathaniel Shiiki presenting his poster.

Elliot Shannon presenting his poster.

Tiffany Regier presenting her poster.

Show Moves to the Chiricahuas!

Lab fieldwork has shifted from the Flight Lab at the University of Montana to the Chiricahua Mountains, a “sky island” in southeastern Arizona. Here we will work at the Southwestern Research Station (SWRS), where the Lab has conducted hummingbird research for 35 years.

Southwestern Research Station

Our focus this year will be on how hummingbirds might use behavioral thermoregulation as a means of dissipating body heat accumulated during hovering bouts when environmental temperatures are warm. Motivation for this work came when our measurements of passive and evaporative heat dissipation during hovering appeared insufficient to deal with the extra heat projection that occurs due to the mechanical inefficiency of hummingbird flight muscles.

During this trip we will conduct two studies, one in the laboratory and one in the field. In the laboratory undergraduate researcher Elliot Shannon will offer hummingbirds a choice between a perch at ambient temperature and one that is artificially cooled to several degrees below ambient temperature. The experiment will be run across a range of environmental temperatures. The initial hypothesis is that when temperatures are warm (mid to upper 30’s °C) that the hummingbirds will choose the cooled perch to dissipate heat following hovering bouts. Normally ambient temperatures during the day are sufficiently warm that we can use naturally occurring temperatures cycles for such experiments. However, this year temperatures were unusually mild so we ended up using heat lamps to increase ambient temperature (yes, everyone laughed at us). Experimental trials were using the three common hummingbird species at SWRS: blue-throated mountain-gem (AOS just changed the common name from blue-throated hummingbird), Rivoli’s hummingbird, and black-chinned hummingbird.

Flight arena used in perch-choice experiments. Actually experimental trial involving a male blue-throated mountain-gem.

The field experiment, conducted by undergraduate researcher Nathaniel Shiiki, tracked hummingbird use of perching locations around the station’s feeder patch throughout the day. Included in the protocol was placement of iButtons at typical hummingbird perches to measure perch-microclimate temperature cycles as well as trail cameras on feeders to monitor feeding frequency and duration across a range of daytime temperatures. The primary purpose of this work was to see if hummingbird perch selection throughout the day was consistent with the intentional selection of cool microclimates to dissipate heat accumulated during hovering bouts.

PlotWatcher 6 trail camera and iButton (inside the cup) setup on one of the feeders.

2019 Field Season Begins in Montana!

As usual the lab’s field season starts with a trip the Flight Lab at the University of Montana to work with long time collaborator Dr. Bret Tobalske. The main goal of this trip was to continue our work on heat dissipation during hovering in calliope hummingbirds (Selasphorus calliope), and to begin looking to extend our work on heat dissipation during flight to other bird species.

University of Montana Flight Lab

We began our work by measuring total evaporative water loss during hovering in calliopes. We actually started this work two years ago, but needed to increase our sample size. There is no simple way to make this measurement beyond getting birds to hover continuously in a metabolism chamber.

Metabolism chamber used in our study.

Once the bird is hovering evaporative water loss is measured using open-flow respirometry. As you might imagine this also requires a high flow rate. In our case 8 L/min!

The Sable Systems Field Metabolic System used in this study and our trusty iMac Pro running Warthog Software.

Once these measurements were made we switched gears and began experiments designed to help us understand how hummingbirds might behaviorally thermoregulate to dissipate heat accumulated during hovering at high temperature. We were in luck because we were able to get some time in a temperature controlled room for a few days to do our work (thank you Dr. Zac Cheviron). Bret’s graduate student Tony Lapsansky collaborated with us on this project. Our experiment involved a large acrylic flight chamber, and we used two FLIR Infrared video cameras to track perching and hovering surface temperatures over a range of environmental temperatures. We also recorded each trial using GoPro Hero 6 cameras that will be used to assess kinematic changes in hovering flight that might occur across temperatures.

Short video of one of our temperature trials.

Overall the trip was quite productive and we were really pleased with the quality of our data. Next, in about a week, we will be off to Chiricahua Mountains in southeastern Arizona and the Southwestern Research Station!