I was recently told that there are organizations, at least in the United States, that study migration of monarch butterflies by tagging them. The purpose, as in most animal migration monitoring, is to learn as much as possible about the animal, keep that animal population safe, and enable researchers to educate people regarding various species.
While banding and tagging of larger animals doesn't seem so difficult to me, I'm wondering some specific things about tagging a butterfly.
What does the tag look like?
What information does it contain?
How and where on the butterfly is it applied in such a way that the animal isn't damaged, either at the time or later, and so that it doesn't fall off?