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Annual Yosemite National Park Butterfly Count

Jeffrey Glassberg, Karen Amstutz, and Ryan Carlton searching for butterflies.

Jeffrey Glassberg, Karen Amstutz, and Ryan Carlton searching for butterflies.

Yosemite National Park initiated its second annual butterfly count in the Tuolumne Meadows area in summer 2013. Yosemite coordinates this event in association with the North American Butterfly Association (NABA), an organization that conducts long-term monitoring of butterfly populations all over North America. The purpose of the NABA counts is to determine how many species and individual butterflies can be observed within a 15-mile diameter circle, during a 24 hour period, within the same date-span year after year. Participants spend the day gathering data toward long-term monitoring; raising public awareness toward butterfly conservation; and socializing and having fun with other butterfly devotees.
 
Ruddy Daggerwing (Marpesia petreus)

Ruddy Daggerwing (Marpesia petreus) butterfly

On the morning of July 29, 2013, a jubilant group of butterfly experts and enthusiasts met at the Lembert Dome parking lot in Tuolumne Meadows. As each person introduced him or herself to the group it was evident that this day was marking history in Yosemite. The thrill of so many expert lepidopterists from around the state and beyond, convened together in Yosemite’s beautiful high country, sent an electric current of excitement running through the group.

Following introductions, instructions, and the dissemination of count datasheets, the larger group broke up into 5 smaller groups, each led by one or two butterfly experts. Each group was responsible for counting and identifying as many butterflies as possible in their respective area. The butterfly count circle included such hotspots as Dana Meadows, Gaylor and Granite Lakes, Saddlebag Lake, Ellery Lake, Warren Canyon, Hall Natural Area, lower Lee Vining Canyon, the western edge of Mono Lake, and Lundy Lake.

The day was intermittently cloudy, sunny, and breezy. The butterfly counters had to read the weather to know where to find the butterflies, and search all habitats for species that specialize on different plants, varying degrees of moisture, or that exhibit different behaviors at different times of the day or under different conditions. All the while, each person had to be completely focused, conjuring a particular search image, depending on the conditions, circumstances, and target species. The leaders were not only adept at identifying species, but also enthusiastic teachers, helping the less knowledgeable participants learn all sorts of facets of butterfly identification and ecology.

At the end of the day, the group convened back in Tuolumne Meadows to share highlights from the day and report their count results. Lively discussions ensued as the experts tried their best to figure out some of the more difficult fritillary and blue species identifications. The final tally for the day was decidedly good, with a fairly high species count considering the high elevation mountainous habitats. In total, 25 participants counted 1761 individual butterflies of 53 species. Of those species, 14 were new species never before observed during the Yosemite Butterfly Count. Highlights were many, including a single Pacific Fritillary at over 10,000 ft elevation, 445 coppers of 8 different species, and a surprising Indra Swallowtail near the road toward the end of the day. Already looking forward to next year’s count on July 28, 2014!

Related Information

  • View raw data results from 2011-2013 [31 kb PDF]

  • Check out an entry (includes photos) from our High Country Notebook Blog related to the 2012 event.

  • Interested in other annual events to help you connect with your inner naturalist? Each year, tens of thousands of volunteers across the Americas join together annually during the Christmas Bird Count. The event provides a full day to celebrate birds. We take part here in Yosemite - learn more!
 
2013 Butterfly Count Participants
2013 Butterfly Count Participants

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Half Dome Permit

Hiking to Half Dome? Permits are now required seven days per week when the cables are up (typically late May through mid October, conditions permitting). More...