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Now that the late, cool northern spring is thinking about settling into summer, the concern shifts from finding anything to finding those species that will not fly again this year: the vernal specialists with a single generation. As it happens, a number of these spring fliers belong to a group of butterflies know as hairstreaks — “hair” for the tiny tails many kinds trail from their hindwings, “streak” for their stripes, or perhaps derived from their zippy flight. Many hairstreaks make their appearance early, then are seen no more.
I’d had good luck early on finding Henry’s elfin in the Texas Hill Country, the Atala hairstreak and Sweadner’s hairstreak deep into Florida, and frosted elfins along the Georgia border. Returning west, I was delighted to come across both the Siva hairstreak and the stunning, elusive Arizona hairstreak in the Magdalen Mountains of New Mexico — the former apple-green, the latter like a bit of Navajo turquoise with vermilion inlay and sapphire dust sprinkled on top. Each species has its own particular habitat and larval host-plant — oak, juniper, mistletoe for the Great Purple hairstreak — and none can be taken for granted as far as appearance, flight, and finding them goes.
For almost half a century I’d longed to see the Sandia hairstreak — discovered by a 4-H kid in 1959, and named and scientifically described by population prophet Paul Ehrlich. Goldy-green with a white stripe below, it blends perfectly with its larval host, beargrass (Noline) a narrow-leaved yucca. I found the plant, and the butterfly, in its type locality (= place of original collection and description) — the Sandia Mountains, outside Albuquerque. What very different worlds: the beargrass mounts, the huge nearby casino, the city beyond. Hairstreaks, with their specific botanical needs and moist-spring ways, may be some of the first butterflies to feel the warming and drying, and to abandon historical ranges. But the Sandia is still there for now. Certain other species, even brighter green, have already much contracted.
A few days later, when I took the ferry 26 miles across the sea to Catalina Island, the Avalon hairstreak was not there — at least I failed to find it. One of the narrowest endemics in the world, it flies nowhere else. The prolonged southwestern drought — though not apparent this past January in San Diego! — has affected many plants and creatures, as the much-depleted monarchs showed. But the Avalon does have a later generation, and I’ll look again. Meanwhile, its nearest relative the Gray hairstreak, was dancing by the dozens in the late-day sun on baked rocky hilltops in the Mojave Desert. But in stark contrast to the highly restricted Avalon, the Gray is a great generalist — common, widespread, and nowhere a surprise to see, all season long.
The hairstreak genus Mitoura, however, feeders on evergreens and mistletoes, are specialists that must be seen in spring, and only in certain places. I’d hoped to spy the one known as Muir’s hairstreak as close as I could to Muir Woods in Marin County — in a grove of Sargent Cypress high on Mt. Tamalpais. So forty years after the Dharma Bums circumnavigated Tamalpais, I sought John O’Mountains’ butterfly above “his” woods. Mitoma muiri didn’t show. But a couple of days later, high in the coast range of Mendocino National Forest, on a ridgeline thick with McNab’s cypress, I found myself in the flashing company of scores of M. muiri, and camped among them. It was in the deep satisfaction of this hard-won encounter, and all the others, that I bumped down the long dusty road and up the longer concrete stripe of I-5 — many weeks, many miles, many butterflies since Lodi.
And there was one more hairstreak to be seen before the cold rain of a Washington La Niña May settled in: flitting over the kinnikinnick among camas, violets, and shooting stars, the hazelnut-and-frost mites called hoary elfins — some of the loveliest and most ephemeral of the hairstreaks of spring.
Photo: David G. James