The neat thing about the large swallowtails (but not to a photographer unless he or she specializes in blurs) is their habit of fluttering their wings. They seem to visit flowers in full sun because they are energized by the warmth, but the reason for the fast flutter is that they must hold themselves upright when nectaring.
It’s quite a challenge to photograph them and stop the action. Even though my flash was on, it didn’t matter.
Bayou George, FL