I have always found butterflies to be quite elusive when I am trying to take photos of them, and when I don't have a camera with me they tend to be easier to find. Fortunately the Calgary Zoo has an enclosure just for butterflies. Although it is seasonal the variety that is there cant be matched. Also the environment is controlled and ideal for many types of species, you can find them in various spots usually fairly docile and easy to photograph.
Nikon D7000 1/50 sec. f/5 ISO-200 at 40mm
Nikon D7000 1/80 sec. f/7.1 ISO-200 at 40mm
They even have fruit laid out for the so its nice to see them feasting away while you take some photos and try not to get to over heated as it can be quite humid inside the enclosure.
Nikon D7000 1/80 sec. f/7.1 ISO-200 at 40mm