Part 2 – Reintroduction

When last I left you, we had explored the history of the names and relationships of our northwest green elfins. An introduction to the characters used in identification of our “greenies” was also given. This time around we get serious. You will remember that the physical characters distinguishing green elfins are subject to variation; surprise…surprise…surprise. This is certainly because we do not inhabit the mini-environment they do, for the green elfins make no mistake. We must figure out who is who based on unreliable appearances and any behavioral or other characters that can be found. 

INTRODUCING THE CAST

We are blessed with three species of green elfin in Washington-Bramble Hairstreak, Western Green Hairstreak and Sheridan’s Hairstreak. Two of them have been given subspecies determinations in Washington, though we will barely touch on this here. Also, you should know that there is disagreement over how many green elfins there actually are in North America; even the experts dissent.

First under consideration is the Bramble Hairstreak (Callophrys perplexa) named by two fellas, Barnes & Benjamin, in 1923. The name perplexa reflects the uncertainty surrounding this creature from the very beginning. When the study of North American butterflies was young, the first green elfin was described from California. Usually, the earliest butterflies described are among the most common. In this case, the first described green elfin was a very restricted and local butterfly, found only along the coast north of San Francisco. Unfortunately the name given to this elfin, dumetorum, was widely applied to the widespread and common west coast species. This error has been corrected after much wrangling and confusion, and the common species is properly known as perplexa. You may still see our Bramble Hairstreak called by the name dumetorum. But the confusion does not die here either. You see, my friends in Oregon have discovered populations of what may be the “real” dumetorum in the Oregon coastal ranges, flying with the Bramble Hairstreak, and these populations may be an “intermediate between California dumetorum and populations of the Western Green Hairstreak (Callophrys affinis); or they may be the same species. In a few years we may find out that we indeed have butterflies that must go under the name dumetorum. Whew!

We have two subspecies of Bramble Hairstreak. Its range best determines the Bramble Hairstreak, but once one becomes familiar with its identifying features, it is easily recognized.

Dorsal Ground Color: Both males and females are brown dorsally, with females often having an orange suffusion. Of course this surface is not often seen in the wild, and even if the specimen is in a laboratory, the degree of wear can make determination on this character alone very difficult.

Ventral Ground Color: The green color tends to be a darker, grass green, though bluish and yellowish tints are not uncommon. Perhaps most useful is the fact that on the ventral forewing, the green is restricted to the foremost edge, trailing around the wing tip a short distance, with the remainder of the wing gray or brown. Our other green elfins are predominantly green on this surface.

Ventral Postmedian White Line: These lines are notoriously unreliable as absolute indicators, but there are some

tendencies that are useful. The Bramble usually has a curved row of spots, following the contour of the outer wing margin. This row is usually incomplete, the foremost or aftermost (or both) spots being absent. Many have only two spots present in the band, so the shape is indeterminate. These spots have black edging basally, and sometimes just a trace of orange as well. The populations in Klickitat County (oregonensis) usually have a more complete white line.

The next green elfin we shall consider is the Western Green Hairstreak (Callophry, affinii). William Henry Edwards named this butterfly in 1862. (You will see many butterflies with Edward’s name appended-he was prolific.) Originally described from Wyoming, the Western is now known to be widely distributed in the intermontane west (between the Rocky Mountains and the Sierra-Cascade Mountains). Our populations are distinguished as subspecies washingtonia, named by Clench in 1944. The Western Green Hairstreak can easily be confused with Sheridan’s, but habitat and behavior are very conclusive. Here are some useful features.

Dorsal Ground Color: As noted earlier, this surface is not usually visible in the wild. In the lab, it is a distinctive

character as Westerns are brown to fulvous (orange), even more orange than in the Bramble. Sheridan’s are dark grey.

Ventral Ground Color: As usual with green elfins, this color varies a lot. Usually Westerns are paler green because they have fewer dark scales; they also tend to more bluish and yellowish tones. In contrast with the Bramble, the green on the ventral forewing occupies most of the wing surface; this feature is shared with Sheridan’s.

Ventral Postmedian White Line: For a long time this butterfly was known as the Immaculate Green Hairstreak.

Not so! In Washington this butterfly almost always has some white line. It may be quite faint. The line is usually straight, not curved, and often is not composed of individual spots, but conjoined together.

Our last green elfin is Sheridan’s Hairstreak (Callphrys ,heridanii), also named by Edwards, in 1877, and also from

Wyoming. We list two subspecies of this butterfly from Washington, and there are two distinct populations, but these names may be misapplied. No worries, we will know them when we see them. Some populations are very similar to the Western; others are distinctive. Some of this will be detailed below.

Dorsal Ground Color: In this species there is virtually no difference in ground color between males and females­

it is a slaty gray color. While some of our other green elfins may approach this color, they are predominantly browner.

Ventral Ground Color: Usually the darkest green of all the green elfins, due to much black scaling. It is not as

variable in this regard as either of the other two.

Ventral Postmedian White Line: This feature is perhaps the most variable in this species. Most individuals will show a prominent straight white line, sometimes very heavy and lined with black. The most extreme of these have been called subspecies neoperplexa, and predominate in the Columbia Basin and adjoining regions. At all elevations in the southern Cascades and Blue Mountains, and at higher elevations elsewhere this white line becom.es less obvious, to the extent that some populations in Klickitat County are immaculate!

FLIGHT PERIOD

Flight periods are relative things. A species may be among the first butterflies to emerge in its the several locales where it is found, but the flight dates may differ radically. An early spring butterfly in the arid steppe emerges in late March; the same species at high elevation emerges in late July. Sheridan’s Hairstreak is among the first non-diapausing butterflies to emerge in the spring. This is because the adult is already developed within the pupa (Chrysalis) before entering diapause the year before. It is ready to go at first onset of good weather. Both the Bramble and Western are what I would call “mid-spring” butterflies, emerging somewhat later than the first whites et al. An example of this timing is at Schnebly Coulee (the location of WBA’s first field trip annually). Here, Sheridan’s cavort in the canyon from late March through April, where on the ridge above, Westerns sport from the middle of April through May. A similar pattern occurs at Chumstick Mountain where Sheridan’s begin their flight sometime in late May (give or take based on snowpack) and Westerns sometime in late June. Brambles are not really adjacent either of the other two, so comparisons are not as dramatic, but they emerge later than Frosted Elfins, which are equivalent to Sheridan’s as early spring butterflies.

DISTRIBUTION

Distribution of our green elfins provides great aid in identification.

To begin with, the Bramble Hairstreak is the only green elfin in western Washington. The total range includes the western parts of California, Oregon and Washington. It does not occur in British Columbia or Idaho. They penetrate the Cascade Mountains in both Oregon and Washington only slightly. In Washington there are populations in Klickitat County that are considered a distinct subspecies, oregonensis. All three green elfins are encountered in Klickitat County, although in different habitats and at different times of year.

The Western Green Hairstreak is restricted in Washington to the east slopes of the Cascade Mountains, east through the Okanogan Highlands to Idaho and also in the Blue Mountains. The total range includes most of the western states, in the Great Basin and adjacent arid habitats, and it penetrates to some degree into British Columbia in the Okanogan Valley. Itis usually not found with the Bramble Hairstreak, but often is in the same geographic region as Sheridan’s Hairstreak.

Sheridan’s Hairstreak is the most widespread of our green elfins, found in one form or another throughout the western United States and Canada, though not on the immediate west coast. As has been said, distribution enables us to immediately determine western Washington green elfins, but is not so helpful in the case of the other two.

HABITAT

The habitats chosen by green elfins are often contrasting. While actual sympatry (occurrence together simultaneously) does occur, it is conspicuously infrequent.

The Bramble Hairstreak is always found in forested biomes, at least in the Northwest. Its specific habitat is clearings within the forest, often bum-maintained, or natural breaks in the forest caused by local factors. It is not specific to draws, canyons or hilltops, but usually in open undulating heathland, like that often found in Christmas tree farms.

The Western Green Hairstreak is limited to lithosol (stony-soil) habitats, usually on ridgetops and mountaintops, but occasionally in stony flats with “hilly” contours. These habitats may be entirely within the arid zone, or they may be in lightly forested regions, but above the trees.

Sheridan’s Hairstteak occurs in canyons, draws, or at high elevations, rock shutes. This pattern of occurrence can be from the dry Columbia Basin to high in the mountains, but they always are associated with drainages.

FLIGHT BEHAVIOR

The behavior of adult green elfins is very critical in determining what species you are seeing. This behavior is so regimented that the exceptions prove the rule. All green elfins will nectar on low-growing flowers, so this behavior is not particularly illustrative. However, when not nectaring each species has a particular pattern of perching. Perching is defined as the “at rest” position. In males this is usually related to mate detection; in females it is simply resting.

Despite the differences in purpose between males and females, they generally behave in similar fashion. We will begin from the ground up, so to speak.

Sheridan’s Hairstreaks always perch on the ground, or very close to the ground. In the few locales where they co-occur with Western Green Hairstreaks, such as Chumstick Mountain, this can be a critical distinguishing feature, as the adults themselves are very similar. The flight pattern of adult Sheridan’s is also lower.

Western Green Hairstreaks always perch on top of some sort of shrubbery, usually the highest Big Sage on the hilltop. When you see greenies bouncing about the top of a sagebrush on a ridgetop, you have identified the Western. Of course the nectar sources are lower to the ground, and females may oviposit (lay eggs) on lower plants, but the general impression is clearly one of “bush-perching”.

Bramble Hairstreaks are almost exactly intermediate, perching on low shrubs, for instance salal, lining a pathway through their heath habitats. Rarely does one see Bramble Hairstreak perching on the highest point.

FOOD PLANTS

While this subject is slightly more esoteric and less easily observable in the field, it is important to know that the food plant choices for our green elfins are also distinctive. The major difference is between the Bramble Hairstreak and the other two.

Bramble Hairstreaks larvae feed on members of the pea family (Fabaceae). Actually in Washington only one genus is used: Lottus. In western Washington this is Lottus crassifolius, a plant that is evident wherever Brambles occur here. It is not especially evident during the flight period since it is just beginning to grow, but later it is quite obvious. In Klickitat County, the populations called oregonensis use Lotus nevade11sis, a conspicuous, “cow-pie” shaped legume.

Western Green Hairstreaks larvae use a number of buckwheats in the genus Eriogonium (Family Polygonaceae).

Most records are from Eriogonium sphaerocephalum, but Eriogonium elatum is also used.

Sheridan’s Green Hairstteaks also use Eriogonum, including Eriogonum heracleoides, E. strictum, E. douglasii, E. heracleoides, E. umbellatum, but especially E. compositum.

The presence of these plants is a good indicator for the presence of the butterflies-as always, a good butterflyer is a reasonable botanist.

This little treatise will undoubtedly raise some questions; there is much yet to learn about our green elfins. I hope that this will enable you to begin looking at greenies in earnest. They are just so coool!

G’num2001Vol2No2