there's an idea fixed in my mind;if it's possible to nphotographer birds,also dragonflies (see some images in the forum), why not photograph butterflies when flying? in europe butterflies don't gather as does the monarchs!
All my trials in the last weeks have been unsuccessfull with 70 mm Sigma. yes, to use high shutter speed ... what kind of focal lenght would you counsel? Does anyone in the forum has experience in the matter? Thank you.