This butterfly has population surges, such that it can be very common some years and virtually absent others. N. californica can some years be found common on nearly every trail I hike, even in the desert. In places - Opler (1999) mentions northern California - it can have population explosions that imperil traffic. But the last few years, I hadn't been seeing it at all. Strange, considering the host is certain abundant species of Ceanothus, such as cuneatus and leucodermis. As an adult, it can live a long time (about a year) and overwinter in that stage. There is then a new emergence ca. June.
One of the first butterflies of the year along Cactus Spring Trail and surprisingly common. These overwinter as adults, so not too surprising now that things are beginning to warm up. Good to see they are back for another year. February 27, 2019.
2017 has been a banner year for Nymphalis californica in southern California. I photographed this one on June 3rd along Wildhorse Meadows Road (2N93).
California Tortoiseshell at Big Bear, October 23, 2005.
Same Nymphalis californica, the California Tortoiseshell. The abundance of their host plant - Ceanothus - helps explain their abundance many years.
Ventral of the California Tortoiseshell on the Mt Waterman Trail in the San Gabriels. June 25, 2006.
California Tortoiseshell larva on host Ceanothus leucodermis in the San Gabriels below Sunset Peak. May 1, 2011.