Glenn ... another outstanding picture. As a person not used to flash in distance photography, Isn't flash at this focal length (the subject being so far away ~ 20 - 30 m) of pretty nominal use? How much did it contribute? Look forward to some education on this subject.
Not to steal Glenn's thunder, however, flash is often used in bird photography for two reasons:
1. Fill-flash to bring detail to shadow areas on the bird; and
2. To bring a bit of light into the bird's eye.
I routinely use flash for bird photography at distances much longer than 20-30 metres - up to 50 metres.
I would also be interested to know how frequently Glenn uses flash in his work.