Wintering monarch butterfly population booms with 144 per cent increase

Click to play video: 'Monarch butterfly count increases 144 percent'
Monarch butterfly count increases 144 percent
WATCH ABOVE: Monarch butterfly count increases 144 percent – Jan 31, 2019

The population of monarch butterflies wintering in central Mexico is up 144 per cent over last year, experts said Wednesday.

The data presented by Andrew Rhodes, Mexico’s national commissioner for protected natural areas, was cheered but scientists quickly warned that it does not mean the butterflies that migrate from Canada and the United States are out of danger.

This winter, researchers found the butterflies occupying 14.95 acres (6.05 hectares) of pine and fir forests in the mountains of Michoacan and Mexico states. That’s an increase from 6.12 acres (2.48 hectares) a year ago.

They arrive in such numbers that their population is measured by how much surface area they cover.

This year’s is the biggest measurement since the 2006-2007 period, Rhodes said. A low of just 1.66 acres (0.67 hectares) was recorded in 2013-2014.

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Jorge Rickards, director of World Wildlife Fund in Mexico which participates in the monitoring, cautioned that the butterflies, like other insects, see their annual populations rise and fall and the monarchs have had a declining trend. This year’s number was positive, but there’s no guarantee it will continue.

A monarch butterfly flutters around a field behind Dave Bendlin’s home Wednesday, Sept. 26, 2018, in Milton, Wis. The field is filled with wildflowers and attracts monarchs and other butterflies. Angela Major /The Janesville Gazette via AP

The first monarchs crossed into Mexico more than a week later than usual on Oct. 20, owing to rain and cold along the Texas-Mexico border, Rhodes said.

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“Once in Mexican territory, the butterflies occupied an area that gives us a lot of hope for the future,” Rhodes said.

Scientists said the approximately 15 acres (6 hectares) of coverage should be seen as a minimum for the viability of the migrating monarchs in the future.

WATCH BELOW: Raising Monarch butterflies in your own home

Click to play video: 'Raising Monarch butterflies in your own home'
Raising Monarch butterflies in your own home

Ryan Norris, an ecology professor from the University of Guelph in Ontario, Canada, said it would be dangerous to think the improved coverage in their wintering grounds meant the butterflies were out of the woods.

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“It buys us time, but that’s the best it does,” said Norris, who was in Mexico City for scientific meetings about monarchs.

Norris saw little connection between this year’s increase and the concerted conservation efforts along the butterflies’ migration route, especially in Mexico where the government, with the help of local communities, has nearly eliminated illegal logging inside the butterflies’ protected area west of Mexico City.

“It was a Goldilocks year this year,” he said. “Not too hot, not too cold, it was perfect.”

Chip Taylor, director of Monarch Watch and an ecology professor at the University of Kansas who runs a monarch tagging program, echoed that caution.

In this Sept. 17, 2018 file photo, a monarch butterfly rests on a flower in Urbandale, Iowa. Something catastrophically wrong happened in 2018 to monarch butterflies. Idaho wildlife biologist Ross Winton spent years working with monarch butterflies. With the help of volunteers, he would carefully put a tiny tag the size of a paper hole punch on about 30 to 50 of the iconic insects each summer in the Magic Valley. Then during the summer of 2018 he could only find two to tag. AP Photo/Charlie Neibergall, File
“It’s not going to be replicated next year, not even close,” Taylor said.

Above average temperatures in Texas next year will cause problems for the monarch production, Taylor said. Last spring, cold temperatures north of Texas kept the butterflies there to lay their eggs, but when it’s warmer they wander farther north too soon and the population does not grow as well, he said.

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Loss of habitat — especially the milkweed where the monarchs lay their eggs — pesticide and herbicide use as well as climate change will continue to pose threats to the species.

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