The monarch butterfly grove in Pismo Beach may see a decline in the number of butterflies that winter at the site this year.
Seventeen thousand Western monarchs were counted at the site last year, but this year’s numbers might be lower, said State Parks ranger Jenna Scimeca.
“The loss of habitat is a big thing,” Scimeca said. “But it’s not just one focus, which is why it’s so important to protect the migration sites along the way.”
The Western monarchs found in the small stand of mostly eucalyptus trees at the preserve off Highway 1 migrate down the coast to Pismo Beach in late October. The population peaks between January and February.
Since tracking of monarchs at the site started in 1999, the population has never dropped below 17,000. There are currently more than 10,000 butterflies at the grove.
“That’s looking good,” Scimeca said. “But it goes week to week.”
Recent harsh winters have also been to blame for the declining Western monarch population. Several years ago, the population along the coast numbered around 5 million. Today, that number is about 1 million, according to researchers.
“We are really hopeful that the rain will help with food,” said State Parks Recreation Specialist Dena Bellman. “It’s become quite a tough journey for them.”
The docents at the monarch butterfly grove are encouraging visitors to grow their own small preserves of milkweed gardens.
Milkweed is the only plant that monarch butterfly larvae will eat, and female monarchs will also lay their eggs on the plants.
“We are really encouraging people to plant milkweed, especially our guests who come over from the Central Valley and drier areas,” said docent Peggy Coon.
The state’s Central Valley is a large reproduction area for the Western monarch butterfly, Coon said.
“That’s where the milkweed is really needed.”
Milkweed plants in a five-gallon can be bought for $5 each at the grove, where packets of milkweed seed can also be purchased.
The butterfly grove is open to the public from November through February and staffed between 10 a.m. and 4 p.m. with docents. Free tours and talks are offered at 11 a.m. and 2 p.m. daily.