Filed by Professor Hoot, science and technology reporter
Yosemite National Park has scheduled its annual Butterfly Count for Monday, July 27, and the assignment is gloriously specific: volunteers will spend the day looking for butterflies across a 15-mile-diameter count circle in Tuolumne Meadows. This is citizen science with sun hats, field glasses, and apparently a serious pizza résumé.
The park says the count is coordinated with the North American Butterfly Association’s wider monitoring effort. The standardized counts help track the distribution and relative abundance of butterflies, while making a day in the meadow feel a little like a championship round in which nobody is required to wear white.
A field day with unusually small contestants
Yosemite describes the event as an annual volunteer effort and publishes results stretching from 2011 through 2025. The park also notes that the count sits within a national network of roughly 450 counts. In practical terms, that means a lot of patient looking and a lot of chances for a butterfly to decline an interview by leaving.
The park’s annual summary credits its group leaders and volunteers, along with a pizza donation from the National Wildlife Federation. It also preserves a splendid comparison from Liam O’Brien, who called the Yosemite count the “Wimbledon of the California Butterfly Count Season.” The bracket remains mercifully free of line judges.
What the count is actually for
The fun is real, but so is the recordkeeping. NABA-coordinated counts use a consistent circle and a 24-hour count period so observations can contribute to long-term information about butterfly populations. Yosemite’s page points readers to its historical data and to related natural-history material for people who want to turn one cheerful afternoon of butterfly-spotting into a lasting habit.
Professor Hoot’s field note: A butterfly count is not a race. It is a census conducted by people who have accepted that the residents will not hold still for the clipboard.
For anyone following along from a less alpine location, Yosemite’s Butterfly Count page has the event details and its archived raw-data links. The important thing is to let the volunteers do the counting. The butterflies have a prior engagement with being butterflies.
Sources: Yosemite National Park: Yosemite Annual Butterfly Count; North American Butterfly Association.
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