The California tortoiseshell is known for having population explosions which cause the butterflies to migrate to new areas. The cause of these population explosions is unknown. Their larvae eat various species of Ceanothus.
It is recognized for the top of its wings being orange with big black spots (used mainly for camouflage). The browns and grays of the wing underside make it resemble a dead leaf when the wings are closed. Its wingspan varies from 3.2 to 7 cm (1 1⁄4–2 3⁄4 inches).
Ravens usually prey on a diverse variety of animals including California tortoiseshell butterflies. Ravens are most common to prey on California tortoiseshells in population explosions during outbreak years.