Its amazing how u managed to shoot that silverstreak in F16, handheld and the pic turn out crisp. I would have to use a tripod if i ever do that when I'm in AV mode cos it will automatically lower my shutter speed to 1/6 or 1/4.
Most Butterfly shooter travel light and shoot hand hold. With a little practice and correct hand holding and breathing techniques, one can shoot with fairy high keepers rate down to 1/50s.
Butterfly shooting is rather dynamic , if you try to set up tripod , you could be left standing there foolishly while the butterfly had gone half a kilometer away.