Aeroecology focuses on how airborne life interacts with the atmosphere. Until recently, most bird research in the field focused on how weather affects seasonal migration patterns.
Now a study on California condors has revealed fundamental new insights into the lives of these critically endangered birds.
In a giant computer model, researchers divided California and Oregon into 94 million pixels. They then compared GPS locations of condors with data from each pixel on the position of thermals, air deflected upwards by mountains, land cover, terrain roughness and geographic coordinates.
Contrary to conventional wisdom, they found condors mostly go where there are rising air currents. Locations with good thermals are favored in summer, while terrain-related updrafts are important year-round, especially in cooler months when there are no thermals to ride.
Rising air seems more important than food availability. It affects where condors perch, and how high, far and fast they fly. Meaning that condors use only 2 to 5% of the available terrain in winter and 6 to 11% in warmer months.
The study focused on condors in California and Oregon. However, the findings likely apply to birds in Arizona too – and will help focus the location of future conservation efforts.
Condors have wingspans of over 9 feet and weigh up to 25 pounds. That’s part of why the finding makes perfect sense for birds which can go for weeks without feeding, but barely move a few hundred feet without the help of rising columns of air.
This Earth Note was written by Diane Hope and produced by KNAU and the Sustainable Communities Program at Northern Arizona University. I'm Melissa Sevigny.
