Hairstreak Butterflies

Gray Hairstreak 2

Gray Hairstreak, nectaring

On a recent birding trip to Big Bear in the San Bernardino Mountains, our trip got hijacked by hairstreaks! Hairstreaks are common butterflies found in a variety of habitats here in southern California. On this particular trip, we found two species: the relatively common Gray Hairstreak (Strymon melinus) and the more uncommon Great Purple Hairstreak (Atlides halesus). Gray Hairstreaks are one of the most widespread butterflies in North America, being found in all lower 48 states, southern Canada and northern Mexico. Like most hairstreaks, the Gray tends to fold its wings when landing. This butterfly is easily recognized by the flat light gray coloration, a prominent orange rectangle on the underside of the hind wing, and a line of dark spots outlined in white and orange the parallels the wing margin on both fore and hind wings. The “hair” for which hairstreaks are named are little hair-like extensions on the rear margin of the hind wings. On Gray Hairstreaks, the hair is fairly prominent; it is much less so on some other members of the family, like the Elfins or the Hedgerow Hairstreak.

Great Purple Hairstreak

Great Purple Hairstreak on rabbitbrush flowers

The Great Purple Hairstreak is a larger and altogether flashier butterfly than the Gray Hairstreak. This butterfly is just awash in color, being iridescent deep purple or dark blue on the upper wing surfaces, and matte purplish-gray with red, white, pale green and metallic sky blue accents on the under wing surfaces. Even more startling is the abdomen, which is bright orange on the underside and sky blue on the upper surface. This is a gaudy little butterfly! Great Purple Hairstreaks also have very prominent “hairs”, which are curled and elaborate in shape. We found both species of hairstreak nectaring on the yellow flowers of rabbitbrush (Chrysothamnus nauseosus) along the shores of Big Bear Lake. Evidently, this was a good source of nectar as we saw a wide variety of insects on these flowers. But our attention was held by the Great Purple Hairstreak, thanks to another birder (thanks, Allie!) who put us onto it. One interesting behavioral difference between these hairstreak species is that Gray Hairstreaks often occur in numbers, with multiple individuals being found together on low plants. Great Purple Hairstreaks, by contrast, tend to be solitary and are seldom found near ground level, preferring to perch high in the branches of trees. Thus it was a great pleasure to find one in such a conveniently viewable perch. One note in passing: the beautiful colors and subtle markings on these two butterflies make you really appreciate the sharpness and close-focus capabilities of high-quality optics. The Zeiss Victory HT binocular with its 6-foot close focus performed superbly here.

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