Monarch

We rarely get Monarch butterflies in the wild here, though you do hear the very occasional report. Wonderfully, the Calgary Zoo butterfly room had a Monarch butterfly, so at least I was able to see what a Monarch really looked like and photograph it. We were so lucky last summer to see a Viceroy butterfly in the wild (my very first sighting), which looks very similar to a Monarch.

"The Monarch butterfly (Danaus plexippus) is a milkweed butterfly (subfamily Danainae), in the family Nymphalidae. It is perhaps the best known of all North American butterflies. Since the 19th century, it has been found in New Zealand, and in Australia since 1871 where it is called the Wanderer. In Europe, it is resident in the Canary Islands, the Azores, and Madeira, and is found as an occasional migrant in Western Europe. Its wings feature an easily recognizable orange and black pattern, with a wingspan of 8.9–10.2 cms (3½–4 in). (The Viceroy butterfly has a similar size, color, and pattern, but can be distinguished by an extra black stripe across the hind wing.) Female Monarchs have darker veins on their wings, and the males have a spot called the "androconium" in the center of each hind wing[7] from which pheromones are released. Males are also slightly larger. The Monarch is famous for its southward migration and northward return in summer in the Americas which spans the life of three to four generations of the butterfly."

en.wikipedia.org/wiki/Monarch_(butterfly)