Big Decline in Monarch Butterflies in West Michigan

Several factors have led to a sharp decline in the number of monarch butterflies migrating to West Michigan.

The number of monarchs has definitely plunged, says Stephen Malcolm, a Western Michigan University professor of biological sciences and monarch expert.

"Last winter was by far the worst winter for them on record. They're down to about 7 percent of the area of forest they wintered in in Mexico back in the '90s. So in almost 20 years, 93 percent of monarchs have disappeared."

Several factors have hurt them, Malcolm says. The widespread use of genetically modified crops has had the biggest impact.

Genetically modified soybeans and corn allow farmers to spray herbicides and pesticides on crops, directly killing monarch larvae and adults or killing the milkweed and nectar-producing plants they need, Malcolm says.

That has affected the migration of monarchs from Michigan and Canada to Mexico and been detrimental to some other insects, like honeybees.

The weather has played a role too.

"Things like the huge drought a couple of years ago in Oklahoma and Kansas and places like that created a real problem for milkweed and may have contributed to a population collapse," Malcolm says.

The decline of monarch butterflies has been a trend in recent years, one that we hope can be turned around quickly.