Flight is the sine qua non of birds. (A few non-local birds had, but lost, the capability.) So, why doesn’t this blog show more airborne birds? Unfortunately, they are more difficult to photograph.
Every so often, it is fun to explore flight—in this case the liftoff of a Great Blue Heron. During an upstroke, the wings are bent to displace the least amount of air; during a downstroke, they are spread to displace the greatest amount of air.
A juvenile heron hunting in a field caught my attention.
When a bird takes off from a high perch it first descends using gravity to pick up speed. A take off from the surface necessitates that the wings do most of the work. The first step is to bend the wings so that as they are raised, they will not displace much air.
The wings are then extended and thrust down. The heron lifts off.
On the next upstroke, the wings are again bent at the wrist and twisted so that raising them displaces as little air as possible. The heron has already tucked its neck back into an S curve. 
The airborne heron has again spread its wings on a downstroke. This juvenile’s feathers are moulting. 
What beautiful pictures – so crystal clear!
Fabulous. Your pictures are so inspiring. I learn a lot from your work.