The two monarchs on this photo were one pair of about six in the area. The pairs would fly about with one butterfly on top doing the flying and the one underneath just hanging on, legs to legs and tail to tail. Every once in awhile they would alight on a branch, freeing their legs up just before landing and end up with just the tails touching. When they resumed their flight, the bottom butterfly would reach up to re-establish the grip on the legs. I guess having one butterfly carry the other while flying is a good test to see if the partner is suitable mating material considering the migration to Mexico they have to undertake in the fall. Regards
We like your theory about flight strength and migration, but other butterflies that stay local use the same position. Thanks for sending us your wonderful image.