Watching Washington Butterflies with Bob Pyle: Number Forty Six

The time comes each fall when we must accept that the opportunities for any more butterfly outings have grown thin … when the leaves are coloring up, the temperatures dropping, and the autumn rains not far behind. I’d been holding out for an autumn excursion to the extreme southeast corner of the state, for yet one more looksee after Hackberry Emperor butterflies (see several previous columns) before the season shut down for the duration. The extreme drought this year had left Asotin County crispy and dead and the temperatures had remained punishing well into September. But a little precipitation had finally fallen, the days become temperate, and a narrow window of opportunity opened up.

So, intent upon that one final field trip for the season, I drove to Alpowa Summit, east of Pomeroy, on October 4, and camped there. The next day was forecast to be the last of the warm ones in south- eastern Washington before cool air moved in. The fifth dawned hazy, cloudy, and cold, but improved from there. I continued to Clarkston, then south along the Snake River to Asotin and beyond.

One mile north of Buffalo Eddy, a large, bright orange butterfly flew past me heading north. It seems likely it was either a Monarch (if so, one of very few seen in Washington this year) or a Viceroy. Then about five miles north of Heller’s Bar, just beyond Captain John’s Rapids, a broad sandy bar above the river glowed with three large, prime-bloom rabbitbrushes, and a number of smaller ones. They were teeming with pollinators, including Lepidoptera: many species of diurnal moths, and several each of Juba Skippers, Orange Sulphurs, Western Whites, Gray Hairstreaks, and Purplish Coppers, and one each of Western Branded Skipper, Mormon Metalmark, and what I believed to be a male Checkered White-a great rarity in Washington. The branded skipper is formally Hesperia colorado idaho, found here just a couple of hundred yards from Idaho across the Snake River.

As you continue south toward Heller Bar, you come to a series of three lush green seeps coming down the dramatic basalt cliffs from irrigation above on the plateau. The recent rain had refreshed the seeps, and watercress, goldenrod, and an autumn- blooming tall aster bloomed around them. These attracted Cabbage Whites, Western Whites, Mylitta Crescents, Gray Hairstreaks, and a pair of worn skippers that flummoxed me at first but turned out to be Yuma Skippers (see below). Some of the seeps supported stands of Western Giant Reed (Phragmites australis, native genotype), which is the hostplant of the Yuma Skipper.

As I reached the stretch where hackberry trees (Celtis reticulata) line the roadside above the river, I noticed that a large percentage of them, maybe half, looked dead, and many of the rest were in bad shape. Tapping them produced clouds of a tiny insect, and at first I thought it might have been a defoliating micro-moth. But they were a hatch of a very small caddis, and the trees were not actually defoliated-they simply had dead, shriveled and dried leaves. It must have been heavy stress from the extreme drought, and perhaps also from the intense heat in June, that had caused such a severe response.

After midday, now around 80 degrees F. and mostly sunny, I passed Heller’s Bar at the confluence of the Snake River with the Grand Ronde River. As usual, this place was crowded with fishers, boats, trailers, and RVs, noisy and smelly. But once you turn west and head up the Grand Ronde, you’re mostly on your own.

Here I have searched for hackberry butterflies (Asterocampa celtis) many times, especially since Ray Stanford and Charles Rogers reported sightings just north and just south along the Snake. The Grand Ronde hosts many dense stands of hackberry, and lacks the fishing traffic of Heller’s Bar. However, I was disappointed to find that my own favorite grove was preoccupied by a trailer, so I carried on a little way to my favorite river access and a nice stretch of the small dirt road that I call “Hackberry Alley,” where I may have had a sighting on one previous expedition with David Branch.

By now the day was quite hot, and still. Over lunch in the shade, I made two dramatic observations. First, over the top of a hackberry across the road appeared a big black swallowtail! Or so it looked. But we have only small black swallowtails, and only in the spring. This was a bat! A small one, maybe a Little Brown or a Pipistrelle. It flitted back and forth over the road, over the tree, over me, hunting, in broad daylight: I saw it go for a fly, and miss. Of course, bats do sometimes hunt by day…I have seen it several times, but always in winter, never in summer or fall, or on a hot, bright day.

Second, an obvious nymphalid butterfly appeared, motoring down the middle of the road right toward me…and then right over me, and disappeared! Unfortunately, I had a beer in my hand instead of a net. The whole way it was in the shade of Hackberry Alley, so I didn’t get the color well, but I could tell it was neither black nor orange. Nor was the flight pattern like a lady, either Red Admirable or other. Just before it shot over me, I got a quick image of its shape as it flapped at eye level. The forewings looked somewhat produced, which means slightly drawn out, but rounded, not angled like a falcate lady or a comma-in fact, just like a male Hackberry Emperor! The size, flight, brown-gray shade, and that shape were all correct for Asterocampa. Does this mean I’ve seen it at last? No…I might have, but it leaves me still an agnostic…much as for Bigfoot! But it’s the best I’ve seen yet.

I waded the stream, usually good for Viceroys and various others, but too late and autumnal now. Ditto for the other spots I checked through the cooling afternoon. And so, back to Alpowa Summit, a literal “high point” for Lewis & Clark on their return journey, as for mine. A good Walla Walla wine, a book, and my field notes kept me company into the starry night.

The next day, October 6, came cloudless and blue, but considerably cooler, as forecast. I intended to work the golden ocean of rabbitbrush all the way down the Gorge toward home, and so I did. Autumn rabbitbrush can make a great pretext for an autumn outing, magnet that it is for all comers. There is always the chance of finding rare visitors from the south, as well as the last of the resident species. But there was a cool wind off the Columbia, and not much shaking. Nothing like the diversity of moths on the rabbitbrush as in Asotin, and almost no butterflies. I checked many adjacencies of rabbitbrush and Russian thistle for Western Pygmy Blues, but no cigar! At a dead-end entrance to McNary National Wildlife Refuge off SR 12, there were a few of yesterday’s species. And then at Madame Dorion Memorial Park, near the mouth of the Walla Walla River, a field of rabbitbrush was hopping with whites and sulphurs. I spotted a yellow, and netted it-an Eriphyle (=Western Clouded) Sulphur, the only one of the trip. And then, scanning a long row with my binoculars, I spotted a single skipper. Hoping for a Sachem, I hunted and found it, and it was!-a bright male Sachem with its huge stigmata. Two species not sighted yesterday. And that was that.

There remained only the long drive home down the Gorge and out the Columbia to Gray’s River, and the vaguely sad feeling of the trip, and the season, ending-much as I used to feel as a boy on Sunday nights, and at the end of Summer Vacation. But there were fine things to contemplate over the miles. The pair of Yuma Skippers were the third record for the Snake Canyon (I’d found another October female years ago, and Jim Dillman has found it there since), and only the third locality for the whole state. The Checkered White, if confirmed, would be one of a handful of known Washington records. I’d been seeking it in Washington for fifty years.

In fact, once the voucher (a male who had lived his life and done his business) was spread and photos circulated, it was indeed confirmed-both by Jonathan Pelham and by Arthur Shapiro of UC Davis, the accepted authority on this species and the often confoundingly similar Western White. Yay! This was one of only six or seven of our butterflies I’d not seen within the state. And really, fifteen species total? Not bad for this latitude at this late date, especially after a trying drought. So, definitely a worthwhile field trip-not to mention how good it was to get OUT, in the warmth and sun and wild, among the butterflies, one more time before the rainforest winter.

As for Asterocampa celtis, if (and when!) it can be confirmed, it will be a state and regional record. You can bet I’ll be back next year, hoping it won’t be so stinking hot and dry, and that the hackberry trees will recover. For, as Jon Pelham wrote me afterward: “That emperor ‘sighting’ promotes your further questing! I hope you never capture one only so’s you keep searching so hard! On the other hand, if you catch one…Hoorah! Win-win!!”

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