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Murdock Collaborative Research Conference!!

Today and tomorrow Audrey Smith and I will be attending the Murdock Collaborative Research Conference. This conference is specifically for undergraduate researchers at small liberal arts universities and is sponsored by the Murdock Charitable Trust. This is a pretty amazing meeting that gives undergraduates doing research the chance to shine. Pre-Covid there would be more than 500 attendees from 36 institutions in the the northwest. Attendance was intentionally reduced this year because of Covid (it was totally virtual last year), but the fact that it is live and in person this year is a win.

Audrey Smith kicked off the program this year with her talk on “Use of the Bill as a Heat Radiator by Anna’s Hummingbird, Calypte Anna.” She did an amazing job making all of us in the lab proud! Sadly Audrey was the only student from the Powers Lab to get to attend the meeting as they limited us to 10 attendees thanks to Covid. It would have been great to have Tiffany, Whitney, and Emily here as well. Regardless, all the George Fox students who did make it to the meeting did extremely well which is a testament to the quality of our program and the scholars that mentor our undergraduates in research.

Audrey Smith starting her talk at the Murdock Collaborative Science Research meeting.
Audrey’s title slide for her presentation.

Research during Covid- The Anna’s Hummingbird Project

Well, this past summer did not go as planned. While we did have a couple projects planned for the George Fox University campus much of what we intended to do would be in the Chiricahua Mts in SE Arizona. You know what they say about the best laid plans. When the American Museum of Natural History decided to close the Southwestern Research Station for the year it sent labs across the country scrambling….including ours. Now, our field season had to shift focus to our small population of Anna’s hummingbirds on the GFU campus and my backyard.

What was intended to be two projects on the GFU campus turned in to five. Our biggest challenge was figuring out how to share a limited number of birds, and to pivot a bit on a couple of the projects so everyone could get their work done. Dr. Anusha Shankar, a Rose Postdoctoral Fellow in the Laboratory of Ornithology at Cornell spent the entire summer with us shifting her torpor genomics project to Anna’s. She and Emily Blackwell teamed for the summer building a lab for nighttime torpor work in the shed outside the Powers home. This allowed all the equipment to be under a roof while the bird was outside subject to natural light and temperature. Emily had to change her protocol substantially in order to share birds with Anusha, but when all was said and done both got great results. One highlight of Anusha and Emily’s work was our first use of thermal windows built in to a metabolism chamber that allowed concurrent measurement of surface temperature and metabolic rate. Data from the work will allow us to show that hummingbird surface temperature during the night is a reliable indicator of metabolic state.

Tiffany Regier and Whitney Dobbyn spent the summer tracking thermoregulatory strategies in free-living Anna’s hummingbirds both on the GFU campus and at the Powers home. Tiffany was originally going to do her work in Arizona, but for the second straight year got bit by Covid restrictions and had to settle for work at home. One nice thing about doing the work at GFU is that we had some remarkably hot days allowing us to see if what we were seeing in the laboratory applied to free living birds as well. On key thing that came out of Tiffany and Whitney’s work was how complex and difficult it is to measure radiative heat gains and losses in birds. This is particularly true for flying birds where radiative heat simply does not appear to move quickly across the plumage. We have designed experiments for next summer that will hopefully help us to get a handle these measurements.

Last but not least Audrey Smith was also bitten by Covid restrictions for the second straight year. For the past two years she had intended to repeat studies we have done on cool-climate calliope hummingbird on warm-climate species in Arizona. However, like the rest of us she had to pivot to working with Anna’s hummingbirds. The silver lining to this shift in focus is the Anna’s is a non-migratory species that must tolerate a wide range of climatic conditions being around for both cold winters and warm summers (particularly this summer). In addition, Anna’s is also a winter breeder making them a somewhat unique species that likely have a number of thermoregulatory tools in the box.

The first thing Audrey needed to do was build a flight chamber that would fit inside our Percival environmental chamber. This gave us a chance to learn to use the laser cutters over in our Maker Hub to precisely cut the pieces which we glued together. Because we needed to image the birds with our IR camera we could not close the Percival door so instead sealed if off with plastic to allow for temperature regulation. Our initial plans were to complete trials at 5, 20, and 35 °C. However, the refrigeration unit went out so we could only do 20 and 35 °C.

Two things that had to happen prior to collecting data on a bird was that they had to be trained to 1) feed from the respiratory mask and 2) use the provided perch so that we could get post-flight perching data. Audrey discovered quickly that each bird had their own personality. Some took to the mask and perch easily and others not so much. Eventually Audrey developed some training strategies that worked for most birds. In the end Audrey got some really interesting results that now has us thinking that heat dissipation post-flight from the perch is a critical part of the body-temperature management for flight at warm temperatures. In the video below note how the bird not only heats its bill and feet, but also the leading edge of its shoulder!

While we were disappointed to not be able to travel this summer there were some really good things that came out of Project Anna’s Hummingbird. The teamwork and relationships that were established in many ways was far superior to any previous year. The entire lab functioned as a big family which was truly fun. Things appear as if they will be sort of back to normal this coming year, but even so this past summer was fun. Go Team Project Anna’s Hummingbird!!

Latest Publications from the Powers Lab!!

Studies of zebra finch reproductive energetics in collaboration with Dr. Tony Williams lab at Simon Fraser University. Lead author on both studies was Tony’s form student Dr. Jeff Yap who is currently a postdoc at Auburn University.

https://journals.biologists.com/jeb/article-abstract/224/8/jeb235846/258583/Sex-specific-energy-management-strategies-in?redirectedFrom=fulltext

https://journals.biologists.com/jeb/article-abstract/224/8/jeb235820/237803/Physiological-adjustments-to-high-foraging-effort?redirectedFrom=fulltext

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!