All over the world there are animals on the move. Animals move for various reasons–some move to get to food or water, some move for breeding, and some move to avoid cold temperatures in the winter. Certain species of animals are deemed migratory–basically they move seasonally from one region to another. One of the most amazing migration stories is of the North American monarch butterfly (Danaus plexiuppus), which may travel up to 3,000 miles in the fall to get to its overwintering spot. There are two main populations of North American migratory monarchs–the eastern population that overwinter at sites in central Mexico and the western population that overwinters along the coast of California (see map). However, not all monarchs migrate. The non-migratory monarchs are known as resident populations and these remain on the breeding grounds year round.
Much of what we know about monarch migration is due to the research of Fred A. Urquhart (1911-2002) who developed a love for butterflies as a child and became curious about where the monarchs went in the winter. He began studying them seriously, and starting in the 1950’s he successfully tagged monarchs and plotted their migratory routes. Over the next 20 years, thousands of volunteers helped him tag and track the butterflies. Without Mr. Urquhart’s research, we might not know that there are two populations of migratory monarchs (Urquhart termed these populations the eastern and western) and that the journey of the eastern population ends at sites in central Mexico. This tradition of tagging is still carried out today in various monarch migration projects around the country.
I have a special affection for monarchs. During my college years in Santa Cruz I got to spend time observing them at their overwintering roost at Lighthouse Field. To see thousands upon thousands of butterflies in one place is mesmerizing, and to know their story is inspiring. If you want to learn more about these amazing creatures and possibly help protect them, see our guide to the Migration of the Monarchs . In this guide you will find a listing of books and article titles, as well as Internet resources about butterflies, monarch conservation, and monarch migration projects.