The monarch butterflies’ fall migration is underway. It’s a time when millions of monarchs pass through Texas on their way to wintering grounds in Mexico. But, so far this year, the butterflies’ numbers are far fewer than conservationists had hoped.
“We see the first ones typically in the first week in September, and I haven't seen hardly any,” said Monika Maeckle, who tracks the insects from her ranch in the Texas Hill Country. “I was out there last weekend. I saw three [monarch] butterflies over three days."
Researchers began the year with low expectations for the butterflies, which started the spring in Mexico with the second smallest population ever recorded.
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But wetter and cooler than expected conditions in Texas earlier in the year led some to hope for a rebound.
“It’s not looking as promising as we had hoped,” Kristen Baum, director of the nonprofit research group Monarch Watch, said.
Baum said poor weather conditions in the upper Midwest – where many of the butterflies spend the summer – hurt monarch reproduction.
Monarchs typically ride northern cold fronts to travel to their wintering grounds, and extended heat and dryness in Texas from mid-August into October could also be interfering with the fall migration.
“The Journey North map looks pretty sparse compared to some years ago,” Baum said, referring to a website that tracks sightings of monarch butterflies.
Still, Baum said researchers won’t get a full picture of how many monarchs made the journey until this winter. That’s when butterfly census takers count the monarchs in the mountain forests of Central Mexico where they spend the cooler months.
Migration disappearing?
Regardless of how the butterflies fare this year, the long-term prospects for the monarch migration seem to be dimming. Habitat loss, insecticide use and extreme weather from climate change all pose deadly threats to the species.
“Every scientist I've talked to agrees that the monarch butterfly migration is going away. It’s just a question of when," said Maeckle, who recently wrote the book The Monarch Butterfly Migration: Its Rise and Fall.
But, she said, the end of the migration would not mean the end of all monarch butterflies. As long as there are places where conditions are favorable year-round, they should continue on in smaller populations.
“There are local populations of monarch butterflies throughout the world, you know, Florida, Houston, California, and in San Antonio,” she said.
The ultimate fate of the butterflies may rest on human action.
The U.S. Fish and Wildlife Service is currently considering whether to list the iconic insect as threatened or endangered.
Maeckle and Baum say planting native nectar plants and milkweed to propagate monarchs, and reporting sightings to the Journey North website are two ways people can help.
“We would know more if we had more observations,” Baum said. “Those pieces of information really add a lot of context and help everyone know what's going on.”