California Tortoiseshell

Raising California tortoiseshells can be a wonderful project if the butterfly is generally common in your mountain canyons in the early spring as well as the late summer or early fall.  In between those timeframes, during the months of April, May, June, and sometimes, July, depending upon location and elevation, caterpillars of this butterfly can be found in clusters on several species of Ceanothus including Ceanothus velutinus (mountain lilac).

The two hurdles to raising this butterfly is 1) not being able to recognize its host plant; which this presentation will help you do and 2) looking for caterpillars during years where numbers of this butterfly are limited.

It is true that population numbers of California tortoiseshells can fluctuate greatly in the Western U.S.  Again, before seeking caterpillars, keep close watch on how common this butterfly is in the early spring and fall.