Annual Yosemite National Park Butterfly Count
Following introductions, instructions, and the dissemination of count datasheets, the larger group divided up into six 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 area included such hotspots as Dana Meadows, Gaylor and Granite Lakes, Saddlebag Lake, Ellery Lake, Warren Canyon, Hall Natural Area, lower Lee Vining Canyon, Mono Lake County Park, and Lundy Lake.
The weather that day was predictably stormy, with intermittent showers occurring after 11 am. Butterflies typically don’t fly in inclement weather, and the butterfly counters had to be extra savvy to find any butterflies at all. They systematically searched all habitats for species that specialize on specific plants, varying degrees of moisture, and 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 other participants learn all sorts of facets of butterfly identification and ecology. After several hours of intermittent rain and distractions with finding amphibians and wildflowers, a fun and impromptu meeting occurred at a local coffee shop.
Undeterred by the rain, the group reconvened back in Tuolumne Meadows to share highlights from the day, report count results, and enjoy pizza. Lepidopterist, author, poet, and founder of the Xerces Society, Robert Michael Pyle, led the compilation, while sharing entertaining butterfly stories, and facilitating lively discussions about difficult species identifications.
The final tally for the day proved decidedly good, with an unexpected high species count considering the stormy weather: a total of 40 butterfly species composed of 680 individuals. Really extraordinary was having 41 participants, almost a one-to-one ratio with the number of butterfly species! With so many eyes alert for butterflies, unsurprisingly were some great natural history moments and highlights. The 3 most frequently detected butterflies were sandhill skipper (133 individuals), Shasta blue (102 individuals), and greenish blue (72 individuals). Of all the species detected, 4 were new species (Becker's White, Sylvan Hairstreak, Reakirt's Blue, and Common Checkered-Skipper) never before observed during a Yosemite Butterfly Count.
Highlights were many. One party hiked almost a vertical mile though a boulder field to successfully find 45 heather blues. Several people observed butterflies “sleeping” in the rain. The number of “blues” (255 of 11 species) far outnumbered the number of fritillaries (66 of 3 species). One group discovered 8 zerene fritillaries inhabiting Warren Canyon (having not flown up from lower elevations). The combination of the butterflies themselves, people brimming over with natural history knowledge and passion, and beautiful scenery makes this one day very special. As Liam O’Brien put it, “the Yosemite Butterfly Count quickly has become Centre Court/Wimbledom of the California Butterfly Count Season.” See you at next year’s count on July 27, 2015!
Did You Know?
Yosemite Falls is fed mostly by snowmelt. Peak flow usually happens in late May, but by August, Yosemite Falls is often dry. It begins flowing again a few months later, after winter snows arrive.