Presentation Type
Presentation
Faculty Mentor’s Full Name
Lisa Eby
Faculty Mentor’s Department
Ecosystem and Conservation Sciences
Abstract / Artist's Statement
Birds respond to variable environmental conditions by modulating aspects of their movement. Soaring birds use updrafts associated with surface terrain (i.e., orographic updrafts) and differential heating of the surface (thermal updrafts) to subsidize their flight, and they respond to other meteorological factors such as wind speed and air pressure. I evaluated how environmental factors influence one aspect of flight performance, flight speed, of a large obligate-soaring species, the California Condor (Gymnogyps californianus). Based on previous research, I expected that condors would fly faster in conditions conducive to formation of updrafts. I calculated flight speeds using GPS data collected during January through December of 2019 from 10 condors fitted with telemetry devices in southern California. I linked these location data to eight meteorological variables: downward shortwave radiation flux (DSR), turbulent kinetic energy (TKE), pressure, temperature, precipitation, thermal updraft, orographic updraft, and wind speed. DSR, temperature, and thermal updraft variables were all highly correlated, so I retained only the DSR variable in subsequent analyses. To test for relationships between flight speed and these meteorological variables, I used linear mixed effects models in R. DSR, wind speed, and orographic updraft had significant positive effects (p < 0.001) on flight speed; DSR, which is conducive to thermal updraft formation, had the largest effect size. Precipitation had the only negative effect (p < 0.001) on flight speed. This study presents evidence for previously untested relationships between flight speed of condors and meteorological conditions, which can be used as a model for other obligate soaring species. Our findings provide insight on the environmental parameters that influence condor and other soaring bird flight, which is important in the context of changing weather and climatic conditions.
Category
Life Sciences
Video Presentation
Effect of weather on flight speed of California Condors
Birds respond to variable environmental conditions by modulating aspects of their movement. Soaring birds use updrafts associated with surface terrain (i.e., orographic updrafts) and differential heating of the surface (thermal updrafts) to subsidize their flight, and they respond to other meteorological factors such as wind speed and air pressure. I evaluated how environmental factors influence one aspect of flight performance, flight speed, of a large obligate-soaring species, the California Condor (Gymnogyps californianus). Based on previous research, I expected that condors would fly faster in conditions conducive to formation of updrafts. I calculated flight speeds using GPS data collected during January through December of 2019 from 10 condors fitted with telemetry devices in southern California. I linked these location data to eight meteorological variables: downward shortwave radiation flux (DSR), turbulent kinetic energy (TKE), pressure, temperature, precipitation, thermal updraft, orographic updraft, and wind speed. DSR, temperature, and thermal updraft variables were all highly correlated, so I retained only the DSR variable in subsequent analyses. To test for relationships between flight speed and these meteorological variables, I used linear mixed effects models in R. DSR, wind speed, and orographic updraft had significant positive effects (p < 0.001) on flight speed; DSR, which is conducive to thermal updraft formation, had the largest effect size. Precipitation had the only negative effect (p < 0.001) on flight speed. This study presents evidence for previously untested relationships between flight speed of condors and meteorological conditions, which can be used as a model for other obligate soaring species. Our findings provide insight on the environmental parameters that influence condor and other soaring bird flight, which is important in the context of changing weather and climatic conditions.