E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Nymphalis californica Kluk, 1780
California Tortoise Shell; Tortoiseshells
Family: Nymphalidae (Brushfoots)
Species account authors: Crispin Guppy and Jon Shepard.
Extracted from Butterflies of British Columbia
The Families of Lepidoptera of BC
Introduction to the Butterflies of BC
Photo of species

© Norbert Kondla  Email the photographer   (Photo ID #6250)

E-Fauna BC Static Map
Distribution of Nymphalis californica in British Columbia
Details about map content are available here.

Species Information


California Tortoiseshells cannot be confused with any other butterfly in BC. Females are slightly larger and lighter in colour than males, and the forelegs of males are hairier than those of females.

Immature Stages

Mature larvae are deep velvet black. On each segment are five bright steel blue tubercles, each with branching spines. Between the spines are small white dots, and at the base of the dorsal spines are bright yellow patches that form a yellow dorsal line. Pupae are ash grey with a bluish tint, and the abdomen is grey brown. The head has two blackish projections, and the thorax is mottled with brown. There are black dots on the abdomen (Comstock 1927).


None. The type locality of the species has been restricted to near Belden, Plumas Co., CA (Emmel et al. 1998a). It is unlikely that any genetic differentiation is possible, given the strong migratory movements that would constantly mix populations. The subspecies name herri Field, 1936 is sometimes used for Rocky Mountain populations, but the herri wing pattern is actually a variation resulting from maturation in the mountain environment rather than being due to genetic differences.

Genus Description

The name Nymphalis is linked to the Nymphales (nymphs), the name Linnaeus gave to a group of butterflies primarily consisting of present-day Nymphalinae. Both names were derived from the Greek numphe (a bride; a nymph all too often made a bride against her will by a lascivious god). The nymphs were lesser deities associated with springs, groves, mountains, and so on (Emmet 1991), a theme that was carried forward into genera such as Polygonia and Cercyonis. Linnaeus may have been referring to the forested habitats of many of the species in his Nymphales. The common name "tortoiseshells" refers to the resembance of the upperside of the wings of the butterflies to the mottled yellowish brown "tortoiseshell" of some sea turtles (Comstock and Comstock 1915) that is sometimes used for making combs. The name is shared with the genera Aglais and Roddia because the species in all three genera were originally placed in genus Aglais.

The butterflies in this genus are highly variable in wing pattern and colour, but they all share the same basic irregular wing margins, which includes a lobe on the hindwing resembling a small tail. Comparison of the dorsal and ventral wing patterns of each species shows that they share the same original pattern. Compton Tortoiseshells are now placed in the genus Roddia, as discussed earlier. Some authors also incorrectly place Milbert's Tortoiseshells in the genus Nymphalis rather than Aglais.

Tortoiseshells hibernate in hollow stumps and logs, debris piles, unheated buildings such as cabins and barns, and rock piles. There are seven species of Nymphalis worldwide.


California Tortoiseshells are migratory, and migrate into BC in spring (Coles 1948). In years when large numbers migrate into BC, the larval foodplant, Ceanothus sp., can be completely defoliated over large areas. This occurred in the Kootenays in 1912, and in Lillooet and Kaslo in 1918 (Middleton 1913; Ross 1913; Cockle 1920; Anderson 1923). California Tortoiseshells hibernate in BC in piles of lumber, woodpiles, and cool buildings (Ross 1913; Cockle 1920; Hardy 1947; Downes 1948), with adults emerging in the spring (Hardy 1961, 1962b). The species is very rare or absent from BC in many years, suggesting that winter survival is very low in some years and that migrants from the south may be required to maintain BC populations. In California they migrate north and east in May and June, and south and west in September and October (Shapiro 1976c). The adults have been seen migrating up mountains in California in midsummer, possibly in search of larval foodplants (Tilden 1962).

Larvae feed on Ceanothus species, usually C. sanguineus, in BC (Harvey 1908; Cockle 1920; Dyar 1904b; FIS; CSG). California Tortoiseshells found in coastal BC tend to be larger and paler than those in the interior. The coastal BC California Tortoiseshells are all migrants, and they cannot successfully breed there because their larval foodplant occurs only in very small, isolated populations on the coast. California Tortoiseshells successfully produce one new generation in the summer in the interior, and those butterflies are smaller and darker than the coastal ones. This is the phenotype that was named subspecies herri in Colorado.

Exudations from freshly opening young needles of true firs, Abies, are a major food source for adults in California (Wright 1891) and the butterflies feed on fir sap on Vancouver Island in October (Danby 1891). They also mud-puddle and feed on overripe fruit such as blackberries and apples (Hardy 1961). Spring migrants use early spring flowering bulbs such as crocuses as nectar sources (CSG).


California Tortoiseshells occur across southern and central BC as migrants. They can occur in any habitat and at any elevation.



California Tortoiseshells occur from southern BC south to the northern MEX border, west of the Great Plains. Migratory individuals or temporary populations occur east across southern CAN and northern USA to NY.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
NativeS5YellowNot Listed
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Additional Photo Sources

General References

Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2024-06-12 9:10:44 AM]
Disclaimer: The information contained in an E-Fauna BC atlas pages is derived from expert sources as cited (with permission) in each section. This information is scientifically based.  E-Fauna BC also acts as a portal to other sites via deep links.  As always, users should refer to the original sources for complete information.  E-Fauna BC is not responsible for the accuracy or completeness of the original information.

© E-Fauna BC 2021: An initiative of the Spatial Data Lab, Department of Geography, UBC