Monarch migration: an awe-inspiring spectacle

Guest Blogger: Laura Penner
Natural Heritage Education Leader
Rondeau Provincial Park

September is a great time to come out and enjoy all of nature’s colours. The goldenrod is in bloom, and the vibrant purple blooms of cylindrical blazing star dot the dunes along Lakeshore Ave. You may even see the black and orange wings of a monarch butterfly as it stops to feed on one of these colourful flowers.

This month is migration season for these amazing insects. In late August monarchs east of the Rocky Mountains begin a southerly journey which will take them over 3,000 km to the mountains of Mexico. They can often be seen flying in large groups, feeding on nectar rich flowers along the way until they reach the exact same winter roosts used by countless generations of Monarchs before them.

Monarch butterflies forming a roost during fall migration (Photo Credit: Brett Groves)


Rondeau Provincial Park is a peninsula located on the north shore of Lake Erie. Peninsulas like Rondeau are great places to watch the migration take place as the Monarchs are funnelled along the shoreline, looking for the shortest or easiest route across the lake.

Monarchs spend the winter months in a dormant state in fir trees 10, 000 feet above sea level. The climate of this region provides the perfect conditions for the Monarch’s survival. Temperatures close to freezing, high moisture and a thick canopy are exactly what the Monarchs need to make it through the long winter months.

As the weather begins to warm in March, the Monarchs once again begin to stir. These particular Monarchs have already survived a long southerly flight, the sometimes unpredictable weather of their mountainous roosts, predatory birds and other hazards along the way and are now responsible to produce the next generation of Monarchs. As they fly northward they begin looking for Milkweed plants to lay their eggs on. The offspring of these migrants have a much shorter life span than their parents and therefore it can take up to three generations of Monarchs before we start seeing them in Canada in the spring.

 The Monarch migration is one of nature’s mysteries, one which several Canadian entomologists, Fred and Norah Urquhart, were instrumental in solving. Come enjoy this spectacular event this September in Rondeau Provincial Park before the Monarchs are gone for another season.  And if you are planning a road trip northwards, Science North in Sudbury has recently released an IMAX production on this Canadian Discovery.  You can watch the trailer here .


Additional information

Are you wondering why you have seen very few Monarchs this summer? It’s normal for the Monarch population to vary from year to year but researchers believe that last years’ bad weather throughout their migratory route is the reason for the steep drop in numbers this year. In 2012, the American Midwest experienced extensive droughts which made it too hot and too dry for Monarch reproduction as milkweed plants were stunted and quite scarce. A cold, wet spring in 2013 didn’t help matters much as monarchs are sensitive to weather extremes. Habitat loss is always a major issue, so by planting more milkweed and making butterfly friendly gardens we can all help out.