(Callophrys nelsoni) (Columbia Basin Segregate)

This is a butterfly with a very confused nomenclature! Today it is Callophrys nelsoni but when Dave Nunnallee and I wrote our Life Histories book it was Callophrys gryneus. Tomorrow? Who knows? Callophrys nelsoni is the name given now to all Juniper/Cedar Hairstreaks in Washington and it seems likely or reasonable to assume that the segregate that occurs in the arid Columbia Basin is at least a different subspecies from the segregates that occur in moister and forested landscapes in western and northern Washington. But for now, we can only use the Columbia Basin moniker to separate it from its commoner cousins.
The Juniper Hairstreak in south eastern WA is a rare butterfly that the Washington Department of Fish and Wildlife has designated as a Species of Greatest Conservation Need (SGCN) and it is one of the five species that will be targeted by WBA and myself over the next three seasons to obtain information and data on distribution, abundance, and biology (see article: WBA-WDFW Butterfly Conservation Project. This butterfly season, the Juniper Hairstreak will be the first SGCN that I will be looking for in the Columbia Basin and nearby areas and I very much hope some of you will join me.
The Juniper Hairstreak, like all hairstreaks, is a small butterfly with a wingspan of about an inch and a quarter with brown wings above and below but it is the markings on the ventral surface of the hindwings that are beautiful and characteristic of the species. Hard to put into words, the ventral coloration is a variable shade of brown with striking violet or purple highlights with a crooked white band. There is a variable pale area some-times with variably sized black dots near the small hairstreak tails. The Columbia Basin segregate of this species is found only where Western Junipers (Juniperus occidentalis) grow. The distribution and abundance of these trees in Washington is limited (Fig. 1).

There appear to be two areas in SE WA where Western junipers are more common, Juniper Dunes, in Franklin County north of the Tri-Cities and on the dry hills north of the Columbia River in Klickitat County. Juniper Dunes was an area that supported a significant population of Juniper Hairstreaks in the past but it has not been seen there since 2008. Currently, the only Juniper Hairstreak populations known in SE WA are found in Klickitat County. A survey conducted by the Xerces Society in 2023 discovered four sites in this county supporting populations of the butterfly with numbers seen ranging from 3 to 33.
Very little is known about the biology and ecology of Juniper Hairstreaks, aside from the life history studies that Dave Nunnallee and I conducted more than a decade ago. Eggs are whitish-green and laid singly (Fig. 2).

The caterpillars go through four instars taking between 30-50 days to reach pupation (Figs. 3-4). The caterpillars feed on Juniper needles and their camouflage in later instars is exceptional. In captivity, pre-chrysalis caterpillars wander and they pupate on the bottom of the cage they are reared in. Presumably, in the wild they leave the tree they fed on and pupate on the ground but this has not been confirmed. The chrysalids are 11mm long and can be black or brown (Fig. 5).

Adult behavior of the Columbia Basin segregate of the Juniper Hairstreak has not been fully documented. We know they nectar on early season buckwheats and desert parsley. We also know males are territorial, spending much of their time perching, flying out when other males and insects get too close. The flight period in SE WA is oddly earlier (April-May) than in central Oregon (June-July), and more southerly populations of Juniper Hairstreaks can be double-brooded while ours are single-brooded.
Our first WBA-SGCN field trip in late April will be to Juniper Dunes where we will try to relocate this species in the habitat it used to occupy. Recent (2017, 2023) expeditions to find the species at Juniper Dunes were late in the field season, a mistake we will avoid this year!

By David James

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