California Tortoiseshell

Nymphalis californica is native to the western United States and southwestern Canada, and is migratory in much of its range as well as east across to the Great Lakes (Scott 1986). Habitats are chaparral and woodland . Host plants are shrubs, restricted to genus Ceanothus (Rhamnaceae). Eggs are laid on the host plant in clusters. Individuals overwinter as adults. There are variable numbers flights each year depending on latitude and some large-scale migrations (Scott 1986).

Adults feed on nectar and sip mud. Males perch for females (Scott, 1986).

Not of concern.

One brood per year, appearing in early spring (April to May) and again in August to October.

According to Opler (1999), this species is permanently established only from southern BC south to California, and southern Wyoming to northern New Mexico. Migrants occur as far north as the southern portion of the western provinces.

"Most similar to the Compton Tortoiseshell (Roddia l-album = N. vaualbum), but californica has a black dorsal hindwing margin, not heavily marked with orange-brown as in l-album. There are no described subspecies; the name herri mentioned by Bird et al. is a cool-weather induced phenotype according to Guppy & Shepard (2001). There appears to be little geographic variation in this species, possibly due to the fact that it is able to migrate long distances, resulting in mixing of populations."

Open montane woods south of the Crowsnest, rare migrant elsewhere.

The cylindrical, yellow-green eggs have vertical ridges. The mature larva is velvety black with two diffuse, yellow dorsal lines and orange-brown, branched spines (Guppy & Shepard 2001). Like the Compton Tortoiseshell, this species is very rare or absent in some years; it is unclear if all Aberta records represent migrants (spring) or offspring of migrants (fall). It is possible that californica is able to overwinter in the greater Waterton area wher the larval food plant occurs, although Guppy & Shepard (2001) suggest southern interior BC populations must be maintained over the long term by migrants from the south. Alberta records outside of the Waterton region certainly represent migrants, since the larval food plant does not occur elsewhere in the province.

The larvae feed on species of tea bush (Ceanothus spp.) in the western US and BC (Guppy & Shepard 2001).

On Sorbus sitchensis. The underside of the wing resembles a dead leaf.

The California tortoiseshell (Nymphalis californica) is a butterfly of the family Nymphalidae.

The wings of the California tortoiseshell have ragged edges. The upper sides of the wings are orange with black spots and a wide black margin. The undersides of the wings are a mottled dark brown. Its wingspan varies from 3.2 to 7 cm (1+1⁄4–2+3⁄4 inches).

Caterpillars are black with white spots and hairs. Each segment of the body has seven spines. They eat various species of Ceanothus.

This butterfly is known for having irregular population explosions. Ravens commonly prey on California tortoiseshells in population explosions during outbreak years.