(Host) Monarch butterfly watchers are discovering few monarchs this year. To find out why, commentator Edith Hunter consulted her naturalist daughter, Elizabeth, who lives in North Carolina and raises monarchs. She too has found fewer than usual.
(Hunter) Elizabeth started “tagging” monarchs in 1956 when she was eleven years old. At that time I had read an article about Professor Fred Urquhart of the Royal Ontario Museum of Zoology and Paleontology in Toronto. He was looking for volunteers to catch monarchs, affix tiny pressure sensitive identifying labels on a wing, and release them. The hope was that some might be recovered and their flyways and destinations mapped. Elizabeth became a volunteer. Professor Urquhart’s hopes were realized and their Mexican destination discovered on January 2, 1975.
In the fall of 1997 Elizabeth took a two-month job at Cape May, tagging monarchs. She tagged 4,236 between September 1 and October 31 – not the record, but a very good year for monarchs. Thirteen days after she had tagged one, it was found on the island of San Salvador – only the second off-shore recovery of a tagged monarch since tagging began about 1938.
Monarchs are believed to be reluctant about flying long distances over water since they cannot land on water without getting waterlogged and then may not be able to take off again.
There are many contributing factors to the paucity of monarchs this year, but one is that there were two back-to-back winter storms in the overwintering sites in Mexico that produced severe mortality. That meant fewer monarchs starting north this year.
Other contributing factors are the increasing number of acres planted in genetically modified crops. When pollen from Bt corn coats milkweed leaves it can kill caterpillars who ingest it with the leaves. Milkweed is the only food the monarch caterpillar eats. Also increasingly, huge monocultural fields are planted in Monsanto’s Roundup-ready crops (corn, soybeans, etc). Roundup-ready crops have been modified so they can be sprayed repeatedly with the herbicide Roundup, which kills everything else in the field except the genetically modified crop. Among the things it kills are milkweed that grows among the rows of the crop, and also the native flowers that provide nectar to the monarch butterfly.
Other contributing factors could be drought in the desert area in Mexico that the monarchs have to pass through on their way north (meaning a lack of nectaring sources along the way), bad weather in the U.S. during the critical time in which the first generation of monarchs is growing from egg to adult, and cold weather in the great plains breeding range.
There have been poor years before, but one always wonders if perhaps this time we may be witnessing the beginning of the unravelling of the monarch’s migration.
This is Edith Hunter on the Center Road.
Writer and historian Edith Hunter lives in Weathersfield Center. She spoke from our studio in Norwich.