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Western Overwintering Population, 2014-15

Jan 22, 2015


  • Conservation Stories
  • Population Trends

The western overwintering population looks to be maintaining, with this year's official count being reported at just under 235,000 monarchs. See the official press release from the Xerces Society for more information.  

Monarch Conservation Specialist Candy Sarikonda visited a few overwintering sites in California this winter and shares her experience below. For more first-hand recollection of the western overwintering sites, read this Monarchs in the Desert blog article by Gail Morris, coordinator of the Southwest Monarch Study. She describes her recent visit to western overwintering sites and her observations of how monarchs weathered a storm while she was in the area. 

Visiting the California Overwintering Sites

by Candy Sarikonda

Monarch butterflies east of the Rocky Mountains migrate to Mexico by the millions each winter.  These eastern monarchs have made their way to Mexico for the winter, now finding sanctuary in the high-elevation oyamel fir forests of the Monarch Butterfly Biosphere Reserve.  But most of their counterparts, the monarchs west of the Rockies, have instead migrated to California’s central coast, choosing to spend the winter at more than 200 different sites along the coast.  A number of organizations and volunteers are monitoring their numbers, and early reports suggested the western population may have increased slightly this year.  Knowing this, I excitedly planned a winter trip to California, to document the monarchs staying in two of the groves that have long sustained large populations of overwintering monarchs—Pacific Grove’s Monarch Sanctuary (PGMS) and Pismo State Beach Monarch Butterfly Grove (PSBMBG).

I had visited Pacific Grove back in 2009, where I first witnessed the western monarchs overwintering at PGMS.  That year the western population was abysmally low, and I stared at just two clusters of monarchs in a eucalyptus tree bordering the southern edge of the grove—perhaps 900 monarchs in total.  But my return visit this year was far different.  The old-growth forest had grown even more.  Far more, it seemed to me, than I would have expected in just 5 years.  The trees had grown taller, the forest had filled in, and the sanctuary had an ancient feel.  “The realm of fairies,” I thought to myself. 

I spent three days in late December, visiting the grove repeatedly to watch the butterflies.  The grove changed noticeably throughout the day.  In the early mornings, it was magically still.  Fog graced the trees, wrapping them like a blanket.  The monarchs hung motionless in their roosts, tightly clustered together in the branches of two Monterey pine trees in the center of the grove.  It was easy to miss them, and many visitors did.  Some visitors walked by, wondering aloud, “There are supposed to be thousands of butterflies here.  Where are they?”  And I would slip over to them, pointing out the 22,000 butterflies resting peacefully in the trees nearby.  The gasps of visitors never ceased to bring a smile to my face, as I showed them the close-up photos I had taken with my camera.  More visitors would gather and begin sharing their photos.  Very quickly the monarchs’ magic would spread, revealing itself in the awe of the grove’s visitors.

Around 10am, the fog began to lift each day, and sunlight would illuminate the trees where the monarchs were roosting.  It was then that the mood changed, as the forest awoke, and monarchs would leave the clusters in small “bursts” of a dozen or so butterflies.  As the temperature warmed to 55-57F, monarchs became increasingly more active, leaving the roosts headed due north, or circling throughout the grove to nectar on nearby plantings.  Midday hours were brimming with excitement, as monarchs filled the sky above the grove, skimming the trees or nectaring beside visitors.  And as the day waned, the butterflies would once again gather in the trees, in tight clusters, to roost for the night.  Watching them was a scene I could never tire of.

I then traveled to Pismo Beach, to visit the Pismo State Beach Monarch Butterfly Grove on Christmas day.  I had never visited this grove before, and unsure what to expect, I hoped the docents would be there.  To my great delight, they were, and they had already set up viewing scopes so that visitors could see the monarch clusters up-close.  The majority of monarchs were clustered on the branches of a Monterey cypress, which hung directly over the pathway through the center of the grove.  Docents had placed their scopes to maximize viewing of these clusters, and the excitement was palpable.  As visitors looked up, they audibly wondered where the butterflies were.  Docents would point to the cypress tree, and visitors would then immediately exclaim, “Those aren’t dead leaves!  Those are BUTTERFLIES!”  I lost track of how many times I heard these same words over the course of the day.

I joined many other visitors to listen to an informative and entertaining monarch presentation from State Park volunteer, Heather Biscoe, and then rushed back to the center of the grove to see the butterflies and again take photos.  I wandered through the grove, looking for more butterflies, visiting the nearby creek and later the beach.  This grove had a different feel than PGMS, but what it was exactly, I could not explain.  I relished the peacefulness when few visitors were around, and I could sit quietly and view the butterflies.  As the lighting changed, with day turning to dusk, the butterflies glowed in the sunlight like fire.  Just feet over my head, I could see them shining brilliantly above me.

I felt transported, to another state of mind and another world.

If you have the opportunity, please visit the western monarchs as they winter along the California coast.  Monarchs are present at these sites from late October to mid-February.  Check ahead to see when docents might be available to assist you as you visit.  For a list of overwintering sites, visit the Xerces Society at

Photo journey from Pacific Grove Monarch Sanctuary

Photo journey from Pismo State Beach Monarch Butterfly Grove