We reported last Thursday that California hasn't been immune to the massive drop in numbers of monarch butterflies taking place across the continent. That's still true, but a report released Friday by a prominent conservation group shows that the state had more of the striking migratory butterflies visit in 2013 than in 2012.
According to the Xerces Society, a Portland-based group that advocates for conservation of rare insects and other invertebrates, volunteer participants in the group's annual Western Monarch Thanksgiving Count recorded 211,275 monarch butterflies at 162 sites in the state.
While numbers are down catastrophically from the more than 12 million monarchs reported in the group's first count in 1997, it's up a bit from 2012's total of 144,812. That's enough for Xerces to conclude that California's monarch butterfly population is holding steady for the moment: welcome news as populations plummet across the rest of the continent.
Last year's count covered 26 more sites than in 2012, but even so the average number of monarchs counted per site was still almost 20 percent above that in 2012, at 1,304 butterflies per site.
Of the 162 sites in the most recent count, six were in Arizona, accounting for just 21 monarchs. The remainder of the count sites were in California, spanning all counties along the coast from San Diego to Mendocino. The effort also extended to a few sites farther inland, along the shore of San Francisco Bay in Alameda, Contra Costa, and Solano counties.
The count site with the greatest number of butterflies was the North Beach campground at Pismo Beach in San Luis Obispo County, with 30,293 butterflies counted. That's up from around 28,000 in 2012.
There wasn't good news across the board. The counts in Mendocino and Sonoma were dismally low, with just five butterflies recorded at one of the four sites in those counties. but the famous Butterfly Grove sanctuary in Monterey County's Pacific Grove seemed in line with the state trend, with 13,420 visiting butterflies in November compared with 10,790 in 2012.
While the eastern population of monarchs flies across the Great Plains states to overwinter in central Mexico, Coastal sites like Pacific Grove and Pismo Beach are where western monarchs go to pass the winter. In spring, the western population of the much-admired insect migrates inland toward the Rocky Mountains, their summer range extending across the West from British Columbia through the Great Basin states.
All counting in the annual Thanksgiving event is done by volunteers, and Xerces is already recruiting for the 2014 count. Like the Audubon Society's annual Christmas Bird Count, the Thanksgiving count is a great opportunity for budding citizen scientists who want to help get a clearer picture of how California wildlife is faring in a changing world. More information on the 2014 count is available on the Xerces website.