Where are all the monarch butterflies?

The monarch butterfly population is declining in Michigan and other states.

Michigan and other states are seeing declines in the monarch butterfly population due to climate and farming changes, jeopardizing annual monarch festivals.

Michigan is missing its monarch butterflies. So are DelawareMinnesota and Montreal.

"We go out and are looking, looking, inspecting thoroughly," Holli Ward, executive director of the Michigan Butterflies Project near Grand Rapids, told the Detroit Free Press. Ward, and other butterfly enthusiasts inspect stalks of milkweed — a critical food for monarchs during their caterpillar stage and the only plant the adult monarch will lay its eggs on.

"On a good day, we're looking at hundreds of milkweed stalks — every week, twice a week since early June," Ward said. "We have not seen a single egg or caterpillar."

The monarch butterfly is the only butterfly known to make a north-south migration, just as birds do each year. And like birds, their survival depends on having places to eat, rest and reproduce along the way. Michigan's butterflies are the descendants of monarchs that migrated out of the Monarch Butterfly Biosphere Reserve in Mexico last February.

It's normal for the monarch population to vary from year to year, but this year's steep decline is being blamed on last year's weather. The monarch doesn't fare well in extreme weather and last summer's drought was the worst in 25 years. A cold spring this year also meant that monarchs have been slower to reproduce and migrate.

Researchers noticed last December that the monarch population wintering in Mexico covered less than 3 acres — the smallest area ever recorded. In 1996, the number of butterflies in the area was 18 times greater.

Another factor in the decline is the use of pesticides to treat weeds in the Midwest. Chip Taylor, an insect ecologist at the University of Kansas and the founder of Monarch Watch, said that the American Midwest is a key habitat for monarchs because of milkweed, which thrives along the borders of its cornfields. When farms began to use the pesticide Roundup on corn and soy in the early 2000s, milkweed disappeared, and with it, the monarchs that use it to feed and reproduce, Taylor told Yale 360.

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There are so few monarchs that the Monarch Butterfly Festival, held every August in Michigan's Shiawassee Basin Preserve, was in danger of not having enough butterflies. Typically, volunteers gather monarch eggs from the milkweed growing in nearby parks and backyards and raise them for exhibits at the festival. It's been a tradition that, for $1, visitors can tag a monarch and then visit a database later to see if it made it to Mexico. 

But this year, said Casey Reed, Recreation Coordinator for Springfield Township, there were hardly any eggs. Last year, Reed found a hundred eggs — not a huge number, since a single monarch can lay hundreds of eggs per day. This year, she only found four. 

The festival was saved by a pair of monarchs purchased from a breeder. The butterflies have laid more than enough eggs for the exhibits. It's important to keep the festival going, Reed said. This isn't just about admiring butterflies, it's about teaching people how to save them too. 

Meanwhile, in Kalamazoo, Michigan, the Kalamazoo Nature Center has decided not to not stock its butterfly house this season because of low numbers and officials are concerned there won't be enough butterflies for an upcoming monarch tagging workshop, which trains volunteers to monitor local butterfly populations.

"I have seen about a dozen monarchs over the last month," said Ashley Anne Wick, Biological Research Director at the center, "compared to the dozens a day I used to spot when I was younger."

Still, Wick said, it's not all bad. While butterflies overall are dwindling, a few species are doing inexplicably well. The red-spotted purple and the great spangled fritillary in particular are out in large numbers this summer.


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