I. erratica, previously poorly known, has been found to be locally common between southwestern British Columbia and the San Francisco Bay region of California. It is an early spring species, flying progressively later toward the north; extreme dates are 23 March and 8 August. Adults typically occur at beaver ponds but inhabit other fresh-water habitats as well. Behavior is atypical for Ischnura but rather similar to many species of Enallagma and Coenagrion. Other attributes of the species indicate it may occupy a primitive position within the genus.