Travis Draud

Date Approved


Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department or School


Committee Member

Jamie Cornelius, Ph.D.

Committee Member

Peter Bednekoff Ph.D.

Committee Member

Cara Shillington Ph.D.


Energy is the currency of life, where a surplus allows survival and reproduction and a longstanding debt leads to death, yet monitoring energy expenditures in free-living animals has been relatively limited by available technology. Radio transmitters that have been specially modified to detect heart rate, however, allow for real-time estimation of energy expense in free-living, behaving animals. Red crossbills live at northern latitudes year-round and breed opportunistically throughout much of the year. They therefore offer a unique opportunity to examine the ecophysiology of different life cycle stages under drastically variable seasonal conditions. Here we present heart rate data of free-living, non-breeding and breeding red crossbills in the summer and winter. We discuss these variables in the context of red crossbills’ unique opportunistic and nomadic annual schedules and the highly seasonal conditions of our field site in Grand Teton National Park.