Some folks say that this lovely lepidopteran is the smallest butterfly in the world. We aren’t completely sure that is true, but it is safe to say that this is the smallest butterfly in California and possibly in North America. The wingspan of the western pygmy blue (Brephidium exilis) is only about 13 mm or about 1/2 inch. The wings of this alluring creature are a shimmery copper, marked with dusky blue on the inside and edged in white.
Although it is relatively common in alkali habitats such as salt marshes, the species can be hard to find because of its diminutive size and flying habits. Look for this tiny flutterer along the MVSD Service Road near McNabney Marsh July through early October. The males fly low over favorite host plants, like Atriplex (saltbushes), looking for receptive females. Saltbushes and Suaeda are where females lay eggs and caterpillars feed. If you spot one you will likely find dozens or even hundreds within a few square meters of habitat!