Monarch Butterflies moving south

Nature Notes for September 29, 2017           

On September 20, the photo below popped up on my Facebook page, with the note: “Stopped in my yard for a slurp”. While I am often treated to Jean Huffman’s photos of flowers and six- and eight-legged creatures that inhabit her yard, this one was special. This Monarch butterfly was tagged. 

 Tagged Monarch visited my neighbour's garden

photo © Jean Huffman

Thanks to the magic of Facebook, I soon learned that this butterfly had been tagged the previous day at C.R. Gummow Public School in Cobourg by teacher Laurel Merriam. The overnight trip from Cobourg to Port Hope was only the beginning of the butterfly’s journey. It was taking advantage of the flowers in Jean’s garden to put on fat for the long trip ahead. It is possible that it might journey as far as the Michoacan mountains of Mexico where all the Monarchs from east of Rockies spend the winter.

Monarchs have been much more abundant this year than for several years. In the past few weeks, it has been common to see hundreds of them migrating and nectaring on the goldenrod and asters along the lakeshore. Last Sunday, my husband observed over 300 around the A.K. Sculthorpe Marsh in about 1.5 hour. This long stretch of hot, dry weather, so late in the fall, has probably been of benefit to the butterflies. This weather has allowed larvae that otherwise might not have matured into adults to develop and migrate.

Most school children now know that Monarch butterflies migrate to Mexico. Dr. Fred Urquhart of the University of Toronto started to study Monarch migration in the 1930s. By 1940, he had developed a glue with which to affix small tags to a butterfly wing. The tag red "Send to Zoology University of Toronto Canada." He and his wife, Norah, tagged many butterflies, but eventually realized that they needed some help. In 1952 he enlisted the assistance of many Citizen Scientists, although they were probably not called that at the time.

Two local naturalists, Audrey Wilson of Cobourg and Ted McDonald of Port Hope, were among those early cooperators with the Urquharts' project.

Finally, in 1975 the wintering area was found. In January 1976, Dr. Urquhart himself retrieved in Mexico a butterfly that had been tagged in in August 1975 in Minnesota. This was confirmation of migration.

The Monarch Butterfly is listed as Endangered by the Committee on the Status of Endangered Wildlife in Canada. Tagging is one way to monitor population trends of this species. The tags have been modified slightly since the original Urquhart tags. To my eye they look like a small Avery label. If readers are interested in participating in this project, there is information at www.monarchwatch.org.

Another species of butterfly that migrates is the Painted Lady. Many of these have also been observed recently. On the same day that he counted many Monarchs, my husband counted 60 Painted Ladies. This species, which occurs on all continents except Australia and Antarctica, has been the object of study by a team from the University of York in the U.K. Their findings were published in 2012 in the journal Ecography.

Through a combination of Citizen Scientist reports and radar, it was discovered that Painted Ladies do not simply die in the fall when the weather turns cold. They migrate south again, but at an average altitude of 500 meters. This is so high that the butterflies are out of view of observers on the ground.

Unlike Monarch butterflies which winter in one relatively small area, Painted Ladies travel and continue to breed throughout their migration route. They travel from tropical Africa to the Arctic Circle and back to Africa in the fall. The butterflies that return to Africa are several generations removed from their ancestors that left Africa the previous autumn.

I know of no similar studies of the Painted Ladies of North America. Other North American butterflies that migrate and occur in our area include Red Admirals, American Lady, Question Mark, Common Buckeye and Orange Sulphur. Perhaps there is a study waiting for a researcher on one of the other migrants.

For more information about Monarch butterfly projects involving Citizen Scientists, go to www.monarchwatch.org.