Big rebound for westerns monarch butterflies
News of the week
After decades of decline and the population reduced to one percent of what it had been in the 1980s, western monarchs have rebounded big time.
The Thanksgiving Monarch Butterfly Count, an annual survey conducted by the Xerxes Society since 1997, tallied more than 247,000 monarch butterflies throughout their overwintering sites, the highest total since 2016. Remarkably, this year’s count is over 100 times the count of last year’s count of 2,000 monarchs.
Despite the great increase, numbers are still nowhere near what they were in the 1980’s, when millions of monarchs overwintered in their California habitats. The population stands at five percent of what it was 40 years ago. Though many are celebrating the good news, no one is quite sure why the butterflies have rebounded. “There are so many environmental factors at play across their range that there’s no single cause or definitive answer for this year’s uptick, but hopefully it means we still have time to protect this species,” says Emma Pelton, the Western Monarch Lead with the Xerxes Society.
Monarchs move south
It is still too early to see if this is a trend, but the monarch populations seem to be moving south. In years past, large populations of monarchs have occupied California’s central coast and the San Francisco Bay Area, but Bay Area sites had few or no monarchs this year. Fewer that 600 butterflies were counted in the 200 mile stretch from Mendocino to San Mateo counties.
San Luis Obispo County recorded over 90,000 monarchs, which includes the Pismo Beach Butterfly Sanctuary. The Sanctuary, under the management of California State Parks, had the second highest count for a single site at 20,871 butterflies. Tips from the public lead to the discovery of five overwintering sites on San Luis Obispo and Los Angeles counties, where more than 7,000 butterflies were counted.
Just south of San Luis Obispo, in Santa Barbara County, the most butterflies were counted, over 95,000, with more than 25,000, the largest single count, observed at one site.
It’s all done by volunteers
All of the counting is performed by volunteers, who receive training from the Xerxes Society in counting methods. The 2021 count saw a record number of volunteers take part in the effort. They monitored 283 overwintering sites, which lie mostly along the Pacific coast from Mendecino County, north of San Francisco, south to San Diego and northern Baja, Mexico.
“I actually had more volunteer counters this year than I have in the last 10 years, because there are so many people who care about monarchs and want to help,” says Jessica Griffiths, the volunteer regional coordinator in San Luis Obispo County. “They were out there at the crack of dawn in the cold, scanning the trees with binoculars. Some of the newer volunteers saw monarch clusters at their sites for the first time this year, which was really exciting.”
Since 1971, the Xerxes Society has protected the natural world by conserving habitats for invertebrates. Besides looking out for monarch butterflies, the international organization has recently sought protections for mussels and sponsored research on fireflies.
There are eastern monarch butterflies, too
There are also eastern monarch butterflies in North America. The Rocky Mountains separate the two populations. All monarchs eastern and western, feed on species of milkweed. The Xerxes Society and other organizations sponsor and encourage individuals and organizations to plant milkweed in yards, gardens, and parks.
Both eastern and western monarchs are migratory. Eastern monarchs are found from Texas to New England during the warmer months of the year. They migrate to and overwinter in pine forests in Mexico. Their southern migration includes a route that has them flying through Florida and even over the waters of the Gulf of Mexico. The western monarch has a migration that is not as dramatic. These butterflies live throughout the West and overwinter in California.
Continued work for recovery
For continued recovery the Xerxes Society emphasizes reducing the use of pesticides, protecting existing monarch habitats and overwintering sites, and restoring habitat by planting milkweed and other native flowering plants. Pelton says, “There has been some really amazing efforts by the public that are really working hard to plant milkweed. That does matter. And that is one of the most important ways that we can protect the insect’s populations.” She cautions that research by the U.S. Fish and Wildlife Service for listing the monarch under the Endangered Species Act shows that the insects are losing ground, that they are losing a great deal of habitat and overwintering sites due to development. This means that monarch recovery efforts will need to work with larger entities, such as energy companies and the transportation sector. “But those individual efforts remain crucial,” she adds.
For more environmental news follow me on Twitter @EcoScripsit
This Green Dispatch, normally scheduled for Friday, appeared today because I was just so eager to share the good news.