Point Reyes Butterfly Count 2024

Sharing this report from the Marin Monarch Working Group newsletter:

On July 20th, some 29 volunteers scoured 15 count areas in the Point Reyes National Seashore, Inverness, and Tocaloma areas to record butterfly species seen that day.   This annual count is sponsored by the North American Butterfly Association and this year the Marin Monarch Working Group organized the count. 

A total of 28 different species of butterflies consisting of 394 individuals were observed, including one monarch.  Monarchs should be migrating inland this time of the year.  The highlight was the observation of 7 federally endangered Myrtle’s silverspot butterflies, which inhabit coastal terrace prairie areas.  Its larval food plant is the western dog violet.   You can find information on butterfly counts on the NABA website. 

A note on the name Myrtle’s silverspot butterfly:

According to iNaturalist member djrawlinson and several other community members, the old name for the Point Reyes subspecies was Myrtle’s Silverspot but this name was dropped in favor of what iNaturalist now calls Point Reyes Silverspot (Argynnis zerene ssp. puntareyes). Both names refer to the same fritillary population in Point Reyes, Marin County. The Point Reyes butterfly had always been linked to insects in San Mateo County. Close examination showed that the Point Reyes butterflies were different from the San Mateo ones. In light of this, the San Mateo butterflies were still to be called the original Myrtle's Silverspot. It is accepted that these are now extinct, presumably a victim of urban growth. The Point Reyes Silverspot are alive and well. This fritillary is found at the coast all the way to the north at least through to Oregon but has changes in appearance. To the north, you’ll find Behrens' and eventually Oregon Silverspot.

Point Reyes Silverspot feeding on Grindelia flower at Abbotts Lagoon