Category Archives: Research News

After 34 years of teaching at George Fox University I have decided to retire. This is something I have been thinking about for some time but last February I made the choice to pull the trigger. Many factors have gone into this decision, and I will not go into all them here, but without a doubt now is the time. I have been blessed in so many ways the past 34 years. Since I first arrived here in 1989 I have had the opportunity to teach and mentor countless students, several of whom made the effort to come to and participate in my retirement celebration. It was humbling to listen to their stories of our encounters some of which stretch clear back to my early years. While I have never had the opportunity to have official graduate students I have had the joy and pleasure of working with 80-90 budding undergraduate scientists in my lab over the years who performed well beyond what anyone expected. Even though I set the bar high without exception my students lept well over it. Over the years I have had the opportunity to mentor a few graduate students at other institutions. Hopefully I was able to play a small part in their development as well.

So what is next? Even though I will no longer be in the classroom the Powers Lab will go on. We might no longer have a physical location but research is burned into my firmware. Science is what I do and will continue to do. Next month I will be off to Montana to continue my collaboration with Bret Tobalske and begin mentorship of a former Powers Lab student Rosalee Elting who has just started a Ph.D. in Bret’s lab. I will be moving to the east coast to be nearer family but will make regular trips back to the university to work with respirometry and stable isotope equipment that will continue to be housed there. So, I am not going away, but rather am just entering a new phase. Cheers!

The lab wrapped up a successful year by heading off to Austin, TX and the SICB meeting to share what we had learned. SICB is the primary meeting we attend each year and serves as a wonderful opportunity for the students to strut their stuff, network, and gain international exposure.

The photo above is a team photo for all of us who attended the meeting. From left to right Kendra Wisenbaker, Emily Blackwell, me, Emma Ortiz, and Whitney Dobbyn. All four students presented posters of portions of their work on hummingbirds from the past year. Emily presented her work linking body surface temperature and metabolic state, Whitney presented her work on the role plumage plays in restricting heat loss during flight, Kendra presented her work on post-flight heat dissipation from the perch in free-living hummingbirds, and Emma presented her work on thermal microclimates of perches selected by hummingbirds post flight. All the students did an amazing job! Normally I give a talk at this meeting but decided to take this year off. It was nice for a change to not have to think about a presentation.

Beyond the great science always presented at SICB there were several other highlights from the meeting including a wonderful symposium on heterothermy put together by Dr. Anusha Shankar and Dr. Ken Welch, catching up with old friends, some fun sightseeing, and the amazing food in Austin!

After completing their work in Arizona “Team Torpor” transitioned to Oregon for a second year of work on Anna’s hummingbird during July. Collaborator Dr. Anusha Shankar, a Rose Postdoctoral Fellow at Cornell, joined us for this final leg of the torpor field work.

In addition to extending the work done in Arizona to the non-migratory Anna’s, Anusha was completing work started last year focused on understanding changes in gene expression associated with the use of torpor. For the entire month Anusha and the rest of the team (Emily, Sophia, Santi, and Shenni) turned my shed into a makeshift torpor lab!

The work involved data collection on birds at night then preparation for molecular and histological work during the day. And, of course, Anusha always must fit time in for evening Salsa dancing! It was a very buy month! Below are some photos for you to enjoy.

The lab has been working with Dr. Alexandra Harlander at the University of Guelph for a few years in an effort to understand how keel bone damage (KBD) might impact energy costs in laying hens. This month was actually my first trip to Guelph to oversee a series of respirometry experiments organized by Jacob Brost, a Masters student in the Harlander lab.

This trip brought back multiple memories from my past. First, navigating Canadian customs with equipment is an adventure. I first learned this back in the days when I was working on garter snakes in Manitoba and had to spend an hour with customs explaining some small equipment items I was bringing home from the field for use in another project. It was no different this time around. I carried my small FoxBox (oxygen/CO2 analyzer) on the plane with me and was shuttled to three different customs officers who continually grilled me thinking I was coming to Canada to illegally work. Eventually I passed muster but it is not a fun experience. My second walk down memory lane was having to wear so much protective clothing when entering the buildings where the birds were housed. Reminded me of my days at UC Davis when everyone thought my hummingbirds were going to give all their turkeys and chickens deadly diseases.

During the week I was at Guelph we put the hens through their paces using mask respirometry to measure the cost of running and jumping, as well as resting metabolism. I will say that Jacob was very organized with all experiments scheduled such that we would easily get things done. This included time for things not to work as planned which was a good thing because we were delayed a day due to my luggage, which contained necessary equipment, was lost by the airline.

In the end we got everything done on time and even had time to celebrate!

After a two-year, pandemic driven hiatus from our work in the Chiricahua Mountains in SE Arizona the lab returned in full force to the Southwestern Research Station this June! This was our largest crew ever with seven students (4 from George Fox University and 3 from my collaborator’s lab at Cornell University) plus me to tackle three projects.

We recently published a paper showing that the hummingbird species we work with in Arizona had the capacity to use a shallow form of torpor in addition to the deep torpor normally associated with hummingbirds. Our evidence for the use of shallow torpor came from continuous infrared thermography at night to track shanges in the surface temperature of the hummingbirds. One concern about this method is that we needed to make the assumption that changes in surface temperature correlated with changes in metabolic state. So, this year “Team Torpor” consisting of Emily, Sophia, Santi, and Shenni constructed a metabolic chamber with a thermal window that would allow us to simultaneously measure metabolic rate and surface temperature to test the validity of our assumption that surface temperature is indeed an index of metabolic state.

Last month we used thermal imaging and thermal PIT tags to track heat transfer from the body core to the exterior of the plumage surface in collared doves. This involved using thermal imaging to track the temperature of the external surface of the bird, a thermal PIT tag glued to the surface of the skin over the flight muscles to measure skin temperature, and a thermal PIT tag inserted into the abdominal cavity to measure core body temperature. We thought we could extend this study to a couple of our Arizona hummingbird species that are a bit larger in size. Whitney took charge of this study and has spent the last couple months designing and building what was needed. The abdominal PIT tag was omitted because of the bird’s small size but they were large enough to glue a PIT tag to the skin. We built a small flight arena that allowed us to collect data both during flight and perching. All this worked extremely well.

From the work we have done the past few years on body temperature managment during flight in hummingbirds it has become apparent that dumping extra heat accumulated during flight after landing on a perch is likely important. Most of what we have learned about this comes from our laboratory work. This year we wanted to take a crack at documenting whether or not free-living hummingbirds are using the sme post flight heat dissipation strategies that we have observed in the laboratory. To do this Kendra and Emma spent many hours documenting where hummingbirds were perching around our feeder patch then took thermal images of these locations to assess the thermal environment and also attempted to place protable thermal cameras at known perching locations to see if they could get thermal images of perching birds post flight. This was certainly in many ways the most challenging of our projects!

Overall our trip to SWRS was very successful! Now it is on to analyzing the mounds of data we collected and eventually writing the papers! Below is a selection of photos from the trip for you to enjoy.