Monarch Migration Underway

The annual migration of the Monarch butterfly is in its early phase. About eight years ago, when I photographed a monarch in my back yard in late summer, I had no idea that it was a participant in one of nature’s great mysteries. But a few days later, I picked up Sue Halpern’s “Four Wings and a Prayer,” and learned that the butterfly I had photographed was about to begin a journey of more than 2,000 miles.
The above image was taken on 23 August 2007 in Michigan's Upper Penninsula along the southern shore of Lake Superior. The Monarch was just a few days into its journey, gathering nectar after it had crossed Lake Superior from Canada.
Until 1974, even the destination of the migrating monarchs was unknown. Much about the routes they follow and how they navigate is still unknown. But this much is known: a monarch emerging from its chrysalis in August in Canada will probably fly all the way to Mexico, spend the winter there, and leave in March. Then it will fly north, laying eggs (if it is female) on milkweed along the Gulf Coast in Texas or Florida before dying there. The butterflies from those eggs will continue northward, breeding and laying more eggs along the way. Their offspring continues the northward journey, each living about five weeks.
The genetic rules change in August. These monarchs have a lifespan of seven months. Four or so generations removed from ancestors that left for Mexico the previous summer, they head southward and the cycle begins again.
The mysteries of the migration are being unraveled by hundreds of individuals who capture monarchs in September, place small tags on their wings, and then release them, hoping that the same butterfly will be found in Mexico and the tag number reported. One area where considerable tagging occurs is in Cape May, New Jersey. The geography of the Atlantic coast and the Chesapeake Bay funnels the monarchs down the New Jersey peninsula to Cape May where they face an eleven-mile trip over the open waters of the Delaware Bay.
But many others are involved and more information can be found at the Monarch Watch website: www.monarchwatch.org. And for those who want to track the progress of the migration, check out this website: http://www.learner.org/jnorth.