I captured some birds riding thermals along the Sierra Vista Open Preserves overlooking San Jose Valley. I live for moments like these!
“Thermals are updrafts of warm air that rise from the ground into the sky. By flying a spiraling circular path within these columns of rising air, birds are able to “ride” the air currents and climb to higher altitudes while expending very little energy in the process.
Solitary birds like eagles and hawks often take advantage of thermals to extend their flight time as they search for food.
Social birds that fly in large flocks also use thermals to gain altitude and extend their range during migration.
The sight of dozens or hundreds of birds riding a thermal has been said to resemble the water boiling in a kettle, so the terms kettle or boil are sometimes used as a nickname for a flock of birds circling in a thermal updraft.
Thermals are widely used by birds and humans alike because they make it possible to reach much higher altitudes than could be reached otherwise.
One of the best methods we have yet developed to identify thermals is simply to watch the birds and observe when they begin flying in these spiraling, circular patterns“ (Source: http://www.aerospaceweb.org/question/… )
Personally, even though I know it’s a circular pattern, I can’t stop seeing how they are constantly forming triangles with their flight patterns. Take a second and trace the 3D triangles as they form and twist.
You can skip to 1:22 to see my favorite tracking shot as a bird pulls out of the thermal and glides across the valley!
Filmed on Sierra Vista Open Space Preserve with handheld Panasonic Lumix Fz2500
Song: Melatonin by Phoria