Meet San Bruno Mountain's Callippe Silverspot Butterfly
It's a bird, It's a plane—no it's the endangered Callippe Silverspot Butterfly!
By being strong fliers and a relatively large butterfly, the Callippe Silverspot butterfly brings life to the San Bruno Mountain ridgetops.
Being around the size of a golf ball and living in grassland areas in the San Francisco bay area, these beauties can be spotted on the San Bruno Mountain hilltops. With an orangeish brown and black scallop pattern on the upper wings and white circles on wing edges and scattered throughout the wing with an orangeish yellow background on the underwings, these strong fliers can be seen darting around the San Bruno Mountain top during warm mornings with a slight wind. Historically, they ranged from the Inner Coast Range on the eastern shore of the SF Bay to even the west side of the Bay area near La Honda. Sadly due to habitat loss, these eye catching butterflies are now limited to the San Bruno Mountain and in grassland areas near Oakland Hills and Vallejo. While coloring is similar on both male and female, males appear to be richer in color.
Callippe Silverspot are host-specific and use Johnny Jump up (Viola pedunculata) for their food source as well as using the plant for their beginning life stages. Johnny Jump up is a yellow flower that is low growing and blooms from early January through April in grasslands. By mid-summer the leaves and flowers begin to dry up and prepare their resources for the next season. While the Callippe can nectar on a range of native / invasive plants—such as Italian thistle, Bull thistle, Coast Buckwheat, and Pincoushin—Johnny Jump up is crucial for their survival. Their larva will selectively only feed on Johnny Jump ups and the females will also only use this drying plant to lay her eggs on or around, where they will overwinter. During the spring time, the newly hatched larva will feed on the Johnny Jump Up and create a nest of silk two weeks later. After emerging and conditions are right in May and June, both male and female Callippe will begin their adult stages. Adult lifespan is around three weeks in the early summer or late spring, so it doesn’t leave much time for being lazy! Males will typically flutter around the hilltop in search of a female while females will travel up hillsides to meet the ready males on the hilltop.
While the Callippe Silverspot was placed on the Federally Endangered species list in 1997 due to loss of habitat and declining host plant densities from invasive species, SMC Natural Resource Team has been regularly monitoring the grasslands of San Bruno Mountain to help track Callippe population and their host plants since the 1980s. By recording weather conditions, areas Callippe are seen, and how many Callippe are spotted will help researches in analyzing this data and developing a restoration plan that can help preserve and educate the public about these populations on the mountain.
These butterflies might not be able to voice their concerns over their populations, but there are always ways for you to be a voice or protect the Callippe Silverspot butterflies and their environment. We encourage you to join in any of the multiple restoration projects held by the San Mateo County Parks Stewardship Corps and other restorations programs in the Bay Area. These activities focus on restoring areas back into native ecosystems for our pollinators and other flora/fauna that can re-establish in certain areas to keep them native. By preventing the spread of weed seeds by keeping your clothes and shoes clean before and after being outdoors, it can positively affect any ecosystem. If you are not a big fan of hiking, even planting a native garden focused on helping our pollinators is a conscious step that would help out any area.
If you are ever on the San Bruno Mountain during a warm sunny day late spring or summer, keep your head up and look for these endangered butterflies!