We're Killing Our Monarchs.
Monarchs made headline news when the number of monarch butterflies hibernating in Mexico plunged to its lowest level ever. In early 2014, monarch butterflies were found in only 1.7 acres -- compared to a high of 45 acres in 1996.
The reason is because milkweed plants are disappearing all across the U.S. Milkweed is the monarch butterfly’s only source of substance. Their habitat is disappearing!
What’s Happening to Milkweed?
The milkweed plant is a hearty plant that used to be common among roadsides, grasslands and cornfields from Mexico to Canada and all across the U.S.
It’s the only plant that the monarch caterpillar will eat. After hibernating in Mexico, the monarchs begin their journey north in February or March. But butterflies only live two to six weeks, when they mate, laying its eggs on a milkweed plant.
So the monarch butterflies seen by people in the northern U.S. and Canada are actually a different generation than the monarchs that left Mexico!
Monarch caterpillars need the milkweed plants to grow into monarch butterflies. No milkweed, no monarchs. It's that simple.
No Milkweed. No Monarchs.
The milkweed plant is threatened by many factors: urban development is a primary reason.
Some people cut down milkweed because...well, it looks like a weed.
Over a million acres of grassland habitat in the Midwest have been plowed under for corn and soybean fields.
Milkweed, which grows on the edges of corn and soybean fields, can't withstand the herbicides sprayed on these crops. It's a hardy plant, but not that hardy. Some estimate that the number of milkweed plants has declined by as much as 80 percent with the widespread spraying of weed killer.
The habitat is disappearing….and so is our monarch butterfly.
Monarchs in Mexico
Down in Mexico, there’s another problem: illegal logging of Oyamel fir trees is killing the monarch butterfly's winter shelter. Butterflies clump together by the thousands in these trees after making the final trek down in the fall.
At last count, monarchs only covered 1.65 acres in the forests west of Mexico City, compared to nearly 3 acres the year before. In 1995, at their peak, monarchs covered more than 44 acres.
“The (monarch) migration is definitely proving to be an endangered biological phenomenon." – Lincoln Brower, a leading entomologist at Sweet Briar College in Virginia.