The yearly count of monarch butterflies overwintering in Mexico, released Wednesday, shows an increase of 144 percent from last year's count and is the highest count since 2006. That's good news for a species whose numbers had fallen in recent years, but conservationists say the monarch continues to need Endangered Species Act protection.
The count of 6.05 hectares of occupied forest is up from 2.48 hectares last winter. The increase is attributable to favorable weather during the spring and summer breeding seasons and during the fall migration. Monarchs have lost an estimated 165 million acres of breeding habitat in the U.S. to herbicide spraying and development.
The population of monarch butterflies that spend winter along the California coast dropped 86 percent since 2017, according to a recent count by the Xerces Society, an invertebrate conservation group.
Preliminary results from the Western Monarch Thanksgiving Count, an annual citizen science program, recorded less than 30,000 butterflies overwintering in California, a significant decline from the estimated 192,000 in 2017. The official numbers will be released later this month.
The Migration and Importance of Monarchs
Monarch butterflies, which pollinate many different kinds of wildflowers, are among nature's great wonders. Their annual migration is one of the most awe-inspiring on Earth: Each fall, millions of these striking black-and-orange butterflies take flight on a 3,000-mile journey across the U.S. and Canada to wintering grounds in Mexico's Sierra Madre mountains.
Monarch butterflies are already in danger. Their numbers have decreased by 80 percent in the past 20 years, and this year's count of the number of the black-and-orange butterflies wintering in Mexico was lower than 2017's.
Now, researched reported Tuesday in a Louisiana State University (LSU) press release reveals that two human-caused environmental concerns could combine to pose another deadly threat to monarchs in the future: climate change, and the spread of non-native species.
The yearly count of monarch butterflies overwintering in Mexico, released Monday, shows a decrease from last year's count and confirms the iconic orange and black butterfly is still very much at risk. The count of 2.48 hectares of occupied winter habitat is down from 2.91 hectares last winter.
Overall, monarchs have declined by more than 80 percent over the past two decades.
The monarch butterfly has a new chance at recovery, thanks to an innovative program seeking to crowdsource funding and habitat for the beloved species at an unprecedented scale and pace.
"The Monarch Butterfly Habitat Exchange is a market-based solution for restoring and conserving high-quality monarch habitat on America's private working lands," said David Wolfe, director of conservation strategy and habitat markets at Environmental Defense Fund. "We like to call it an 'Airbnb for butterflies' because it's the only program of its kind that can open the vast untapped potential of large-scale farms and ranches to make habitat available for monarchs, fast."