SF Butterfly Count Finds Good and Bad News

By Ryder W. Miller

Butterfly Counters gathered on June 22 to scour San Francisco for signs of butterflies on the northern peninsula for the 25th year in a row. Despite a low turn out, some of the results were good with rare sightings. Other findings were worrisome.

“We had fewer people, but every year my stalwart leaders get better,” said San Francisco Lepidopterist Liam O’Brien, the count organizer. He said he would like to have more people involved. “All parties brought at least one unique finding to the table and, for me… the Sara Orangetip out on Angel Island – the first in the history of the count – was the big story.”

Butterfly 1 RSN 7-18-19

Calliope Silverspot. Courtesy photo.

Despite the lower number of counters this year, they tied the record for the number of butterfly species seen on the San Francisco butterfly count at 32.

“Its a tricky thing. The number of people on count does not always equate better. It’s not really a day to learn one’s butterflies, but I won’t turn any novice away,” O’Brien said.

There were good results, especially from the San Bruno group and at Angel Island.

“The San Bruno Mountain group pulled in three ‘uniques’ (butterflies that no other group saw). They spotted Pale Tigers, Variable Checkerspotsand 143 (a new record) of the federally endangeredCallippe Silverspot.”

Butterfly 2 RSN 7-18-19

Western Tiger Swallowtail. Courtesy photo.

Results were delayed by the work on Angel Island which upped the species count: #30 the California Tortoiseshells,#31 the Common Wood-Nymph. and, saving the best for last, #32, a single, male Sara Orangetip (A. sara). The Sara Orangetip was the first for the count in 25 years. (Island full of Milkmaids, their host.) Saw only one stray of this years back in SF,” recounted O’Brien. “I saw only my second Erynnis sp. (Duskywings) in the county in 25 years bopping about out at India Basin.”

O’Brien said the weather was perfect that day: 60 to 71 degrees. “The fog stayed out of the Bay and pealed back from the Presidio, which is always a worry to me.”

Butterflies do not thrive in the wet weather, and sometimes migrate. They have worse problems than just the weather. Butterflies are also facing the “insect apocalypse” like endangered bee pollinators. Bug zappers abound at houses all across the country.

“There’s been talk of an ‘insect apocalypse’ and one could notice a drop in overall individuals, but it only takes one to be a new species,” O’Brien said.

He did not identify specific things the city could do better, other than controlling the effects of non native plants, but he did mention some of the programs already underway, like The Green Hairstreak Project in the west side of the city.

The Green Hairstreak with Nature in the City would also like more volunteers for their educational and stewardship program on the west side of the city.

“Butterflies are opportunistic insects and they seem to do pretty well on their own in an urban setting like San Francisco,” O’Brien said. “The generalist who to lay eggs on weeds and things seem to be doing better than the butterflies who still use native plants. A city comes with its own complexities and challenges for wildlife. The ones that need help like the Mission Blue and the Green Hair Streak seem to have many champions, so I would say we’re doing pretty well.”

In related news, Amber Hasselbring responded about the latest year with The Green Hairstreak Project, organized by Nature in the City:

“In the Green Hairstreak Corridor this year, we had a very cold and wet spring and we didn’t see our first Green Hairstreak butterflies in flight until our nature walk on Sunday, March 31,” Hasselbring said. “We are crafting a more involved citizen science effort for the corridor with the help of Liam and a graduate student from San Francisco State University (SFSU), Sarah Gomes. We continue to see strong numbers of Green Hairstreaks and other insects in our habitat sites and throughout the neighborhood, so the project has been successful at restoring the population. We do have a call to action: Nature in the City is looking for three new site stewards for corridor habitat sites. Site stewardship looks like weeding, watering and adhering to our wildlife management guidelines.”


Common Wood-Nymph. Courtesy photo.

Of the many green spaces to see butterflies in San Francisco, O’Brien said though “Alemany Farm is the best place I love seeing butterflies in the City.” But there was disappointing news this year. “If I had seen Gulf Fritilllaries out at Alemany Farm like we have in the last four consecutive years, we’d have broken the record.”


Categories: nature

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