Hummingbird Response to Climate Change in Southeastern Arizona: Field Season 2013!

IMG_2459When school was over last spring the lab hardly had time to breath before we packed up and headed off to southeastern Arizona to start our first full season of data collection associated with the NASA project.  Actually, I (Don) was the first to leave since I am too old to power through a drive from the north to the south end of the country in less than three days.  Katie, Becca, and Joey on the other hand pretty much made it to Arizona at the same time I did but in one less day.  We landed in Patagonia, AZ which would be our base of operations for the summer.  This location is not only central to the landscapes we would work on this year but also near where friend and project collaborator Dr. Susan Wethington (Hummingbird Monitoring Network) lives.

IMG_2520The first week of of the field season was intense training to get everyone up to speed on applying what we had learned in the lab to an actual field setting.  After that the next couple weeks were split between kicking off our work and supporting a collaborative project with Dr. Bret Tobalske (University of Montana).  The collaborative work was an extension of heat-balance work on calliope hummingbirds that we have been doing at Bret’s lab in Montana.  Here in Arizona we added larger size hummingbirds to the mix in the hope of looking at how size might influence various aspects of hovering.

IMG_2952For the balance of the summer our team focused on four key experiments designed to assess the physiological response of hummingbirds to temperature in the field: 1) Thermal profiling of two distinct landscapes, 2) measurement of daily energy expenditure using a modified version of the doubly-labeled water (DLW) technique, 3) assessment of a hummingbird’s thermal load across a broad temperature range using infrared thermography, and 4) assessment of differences in torpor use by hummingbirds that live in different temperature regimes.  We spent a total of 2.5 months in Arizona completing these experiments returning to Newberg on July 18.  The students did a marvelous job.  They worked hard and never complained about the sometimes long days.  Over the next several weeks we will be frantically crunching numbers in preparation for submitting abstracts for the January SICB meeting in Austin, TX.  The deadline is August 26 (YIKES!).

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2013 Field Season Kicks Off With SE Arizona Workshop!

Research planning session at El Coronado.

Research planning session at El Coronado.

This year’s field season officially got underway with a week long workshop in southeastern Arizona. The purpose of the workshop was for the PIs of the hummingbird climate change project to select specific Arizona landscapes to be studied and to agree on questions to be addressed this coming summer. Additionally several interns from various parts of South America who will be working on the project this summer attended the workshop and were introduced to a variety of protocols for assessing nectar resources and measuring hummingbird energetics.

Weighing a hummingbird on our new Sartorius balance!

Weighing a hummingbird on our new Sartorius balance!

The Powers lab used this time to try out a revision of the non-invasive hummingbird doubly labeled water (DLW) protocol. The specific revision involves changing how we measure the initial dose size of isotopic water. To make this method totally non-invasive hummingbirds are dosed by feeding them nectar made with isotopically enriched water. Last summer dose size was calculated by weighing a syringe feeder before and after feeding the hummingbirds. This proved to be problematic as the syringe would occasionally drip creating large errors in our measured dose size. This year we have switched to measuring the bird before and after feeding. Additionally, we have purchased a more precise scale which should also improve the accuracy of our measurements.

The DLW sessions done during the workshop were highly successful! Between the two sessions (El Coronado Ranch and the Santa Rita Experimental Range) we labeled a total of 78 hummingbirds and recaptured 29. Our 37% recapture rate would be the envy of most doing DLW studies!

SICB Meeting 2013!

The lab packed up some of our results from this past year’s research and headed off to the SICB meeting in San Francisco to share them with national and international colleagues from across the globe.  Our work attracted a great deal of attention this year and the students did a wonderful job of exciting our colleagues about what we have been doing.

Nagy

The first full day of the meeting was action packed!  The morning started with a special symposium in honor of the lifetime work of Ken Nagy (pictured), who in the 1970’s developed protocols for using the doubly-labeled water (DLW) technique to measure energy expenditure by animals in the field.  This method revolutionized our understanding of how animals cope with their environments in a variety of circumstances.  When Don Powers was a Master’s student at San Diego State in the early 1980’s he had the pleasure of doing a short project with Ken using DLW to measure daily energy costs in Anna’s hummingbirds (Calypte anna).  This project resulted in Don’s second publication.

DPIV-ImageNext up Don Powers gave a talk entitled “Metabolic Power, Mechanical Efficiency, and Heat Production during Hovering and Forward Flight in Calliope Hummingbirds (Selasphorus calliope).” In his talk Don summarized the results of the work he and Bret Tobalske (University of Montana), along with several current and former research students, have been doing the past several years on maintenance of heat balance in hummingbirds during hovering and forward flight.  The picture on the left is an example of a Digital Particle Image Velocimetry (DPIV) image taken of one of our hummingbirds in flight.  DPIV was the method we used to calculate the amount of metabolic power that was used to run the hummingbird’s flight muscles.

IMG_0838That evening research student Luke Andrew presented his poster entitled “Use of Torpor by a High- and Mid-Elevation Hummingbird Species in Southeastern Arizona.”  The poster summarized data collected this past summer in collaboration with Dr. Susan Wethington of the Hummingbird Monitoring Network on patterns of torpor (nighttime hypothermia) use in broad-tailed (Selasphorus platycerus) and broad-billed (Cynanthus latirostris) hummingbirds.  Even though they put Luke back in a dark corner of the exhibit hall he had good traffic including some well known physiologists.

IMG_1258The lab’s final two poster presentations occurred on Sunday.  Research student Katie Langland presented her study entitled “Use of Infrared Thermography to Measure Body-Surface Heat Dissipation in Free-Living Hummingbirds.”  In this study, also done in collaboration with Dr. Susan Wethington, Katie explored the relationship between environmental temperature and surface heat loss in hummingbirds.  Katie had a busy night as there steady stream of attendees interested in what she had to say.

IMG_1256Finally, former research student and current adjunct instructor in the Biology Department Sean Powers agreed to help the lab out by analyzing some infrared thermography data and presented a poster entitled “The Importance of Female Temperature in the Attraction of Courting Males in Red-Sided Garter Snakes (Thamnophis sirtalis parietalis).”  Sean’s data cast doubt on a long-standing hypothesis that males are more attracted to cold females.  The basis of this hypothesis is that when females emerge from the den they are cold and likely to be unmated.

New Research Students Joining the Lab this Spring!

The Powers lab would like to welcome two new research students, Becca Schroeder and Joey Canepa, starting this Spring.

Becca 3Becca Schroeder is a sophomore biology major with a passion for work in the field.  She will be supported by the lab’s NASA grant and participate broadly in the lab’s work on the physiological response to climate change.  Becca has also received funding from the university’s Richter Scholar program to support a study on how frequently hummingbirds in different habitats use torpor.  After graduation Becca plans to pursue graduate studies in biology.

IMG_0813Joey Canepa is a sophomore biology major who truly enjoys studying animals.  His research will focus on understanding the relationship between daily energy expenditure and environmental temperature in hummingbirds found in different habitats.  Joey’s work will be supported by a George Fox University Richter Scholar Grant.  After graduation Joey plans to earn an advanced degree in biology.

IMG_0324Returning to the lab for another year will be veteran research student Katie Langland.  This past year Katie worked both on red-sided garter snakes in Manitoba, Canada and hummingbirds in southeastern Arizona.  This year Katie will be focusing on thermal loads and surface heat dissipation in hummingbirds using infrared thermography.  Katie’s work is supported by a Richter Scholar Grant.  After graduation Katie hopes to pursue a graduate degree and study some aspect of shark biology.

 

NASA-Grant Research Begins in Arizona!

Katie (far left), Mexican interns, and Dr. Susan Wethington working the banding table and DLW experiment.

Don Powers along with research students Katie Langland and Luke Andrew traveled to various areas in southeastern Arizona to begin data collection on the lab’s NASA-funded project exploring how climate change might impact hummingbird populations and their distribution.  The primary goals for this summer’s work were to 1) complete some basic metabolic measurements for an upcoming paper on how broad-tailed hummingbirds (Selasphorus platycercus) were impacted by two extreme cold events over the past several years, 2) begin collection of infrared thermography data and make metabolic measurements that will help the lab understand how hummingbirds respond to changes in their thermal environment, and 3) develop protocols for measuring daily energy expenditure over a variety of thermal conditions using the doubly-labeled water technique.  During our time in Arizona we had the opportunity to work with four student interns from Mexico who are contributing to other aspects of the NASA project led by lab collaborator Dr. Susan Wethington.  These interns were bright, talented, and a joy to work with.  I am considering supporting a Mexican intern next summer that will focus on your physiological studies and work closely with the labs research students.

Katie collecting thermal imaging data.

Overall the field season was success.  Now the hard work of analysis begins.  Katie returns to Oregon today (July 8) and the entire lab will meet tomorrow to set analysis goals for the rest of the summer.  Needless to say we will all be very busy!  While the lab gets a respite from field work Don Powers will make multiple short trips back to Arizona in late August and September for more DLW work as there are a few more wrinkles that need to be ironed out before next year’s longer field season (April-September).  Let the fun begin!

The slide show below shows a few pictures from our time in Arizona.  Click here to see the complete photo album of our Arizona adventure.

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