This article originally appeared in the Yakima Herald-Republic.
On a warm Saturday morning in late May, a group of people gathered at the trailhead of Snow Mountain Ranch, the 2,000-acre shrub-steppe habitat managed by Cowiche Canyon Conservancy west of Yakima. A handful of people held nets over half the length of their body.
A woman walked up to them from the parking lot and asked, “Is this the butterfly meetup?” It was. Dr. David James, with white, straight hair that nearly reached his shoulders, was leading the group, wearing a T-shirt of a monarch caterpillar in the shape of a question mark.
Walking up the trail, it did not take long for the group to start seeing butterflies. One of James’ favorite factoids is that Snow Mountain Ranch has more species of butterflies, 69 types, than his native England, which has only 59.
James recently published research on a butterfly that follows a migratory route within Central Washington, emerging in the spring in the Yakima Valley and taking refuge from the heat of the summer in the Cascades, returning to the valley in the fall. It’s called the coronis fritillary, and I was hopeful to see it.
I went with James on two hikes this year to track the butterfly, once in late May at Snow Mountain Ranch and a second time in late July up at Bear Creek Mountain. I am hoping to attend another such expedition on Sept. 13 at Snow Mountain Ranch, which will be the end of the migration.
The idea that a species was taking its own annual journey right here within Yakima County fascinated James, who has studied the western population of the monarch butterfly for many years. The monarch makes the well-documented journey from Canada to either California or Mexico, generally depending on which side of the Rocky Mountains they live on. Like the monarch, the coronis fritillary is bright, orange and swift. A relatively common species, it can be found from Baja California to British Columbia.
People gathered for the tour included regulars of Cowiche Canyon Conservancy’s events as well as Washington Butterfly Association members from the west side of the state. Armed with walking sticks, nets and sun hats, the group began to move up the hill, eyes on the watch. Soon, a swing of the net yielded … nothing. A sooty hairstreak got away.
After about 15 minutes, the group split in two.
A quick swoop of a net revealed an ochre ringlet butterfly. But James kept looking back at the back group, which from the sounds of it, seemed to have a flurry of excitement.
“What do they got over there, what do they got over there?” he wondered aloud.
We continued upward, surrounded by the smell of grass and a chorus of crickets as the morning grew hotter.
Some years, the coronis fritillary is abundant everywhere in the spring. “It appears this isn’t one of these springs,” James said.
Then: A flash of orange streaked across the trail ahead.
“There’s a coronis fritillary!” he said.
Minutes later, another one fluttered past. But no one had luck catching one, or getting a decent photo. James walked forward with the net. Why weren't there as many this spring?
“Climate, mostly, and the abundance of natural enemies ... ” he said, trailing off.
Swoosh, and he caught … an acmon blue.
By a small bridge on the trail, the split groups eventually merged. Apparently, the rear group had caught a coronis fritillary, but released it after a few minutes. No chance for me to get a photo.
Just off the trail, James identified a caterpillar as the larva of the anise swallowtail, which mimics bird poop until it grows larger and morphs its defensive strategy.
“It’s in its poop stage,” James said as tourgoers circled and crouched to see it.
The group would slowly disband as we returned to the trailhead, but I was determined to get a better look at this butterfly. The opportunity would come later in the summer, up its mountainous ascent.
Research
There is a dearth of data not just on the coronis fritillary, but on butterflies in general.
That’s likely for two reasons, James said. One, insects are generally studied less than more popular animals like mammals and birds. There also is more funding available for research for “applied” than for “pure” science. Though James is a lepidopterist at heart, most of his research with Washington State University is on the management of insect pests on hops and grapes.
But for 12 years, James has led around 30 or so Cowiche Canyon Conservancy volunteers on a fact-finding mission to confirm what he and Jon Pelham hypothesized in a 2011 paper: that the butterfly has an altitudinal migration pattern in the Central Washington Cascades. James believes other species have similar patterns, but data on them are lacking.
From 2013 to 2024, James and the volunteers went out to document as many coronis fritillaries as they could find. They observed and recorded details on the butterfly’s development, phenology, population size, behavior and movement. As the seasons changed and the butterfly migrated, the volunteers tracked them from the low valley of Yakima to Bear Creek Mountain, about 7,000 feet above sea level, and back down again.
The effort involved dozens of volunteers, support from the Cowiche Canyon Conservancy, and hundreds of hours of recording observations. It was half a lifetime for some young participants: James’ daughters grew up during this time and are now college-aged.
The findings were published this year in a study by James, “Seasonal population biology and migration of coronis fritillaries, Argynnis coronis, in central Washington.” The paper was presented during the Washington Butterfly Association annual conference, which took place in Yakima in June.
Sagebrush violets
To understand when the butterfly emerges, the volunteers also observed its larval host plant, the sagebrush violet. The dormant larvae wait patiently under the ground as spring comes and the sagebrush violet develops leaves. The earliest the shoots of the violet sagebrush were observed at Snow Mountain Ranch was mid-February, but the average was early March. Based on their findings, the larval and pupal stages last about 10 and a half weeks on average.
The earliest an adult coronis fritillary was spotted was on April 29 and the latest was on May 30, with an average in mid-May. Tracking these data points can allow researchers to see how a changing climate impacts the insects’ development and emergence.
Warm weather and sunshine seem to hasten development, and early emergence of the sagebrush violet when winter weather isn’t quite over led to longer development periods, seeming to show that cold is a hindrance.
The caterpillars were hard for volunteers to find, leading James to believe that they are nocturnal feeders.
Abundance varies year to year. About 79 coronis fritillaries were seen in 2016, with a high of 807 observed in 2014.
On June 15, 2023, James said that he saw over 2,000 of the butterflies at Snow Mountain Ranch over the course of three hours.
Of all the plants in the shrub-steppe, the adult coronis fritillary seems to have a favorite. Nearly three-quarters of sightings of nectaring were on the Western giant hyssop, a member of the mint family that has a showy, spiky tower of petals. Other flowers the coronis fritillary used to nectar included purple sage, yarrow, hawksbeard, mock orange, desert parsley, bitterbrush, phacelia, balsam root and dusty maidens.
During the tour participants’ observations, a few questions were raised. One was: Where are the females? The observed sex ratio of the coronis fritillary was puzzling. In the spring, nearly all of the butterflies seen in the study were male. In the fall, it would shift, and nearly all of the butterflies seen were females, who by then were ready to lay eggs.
Though the sex ratio seemed to balance out in the mountains, there were only two observations of mating during the 12 years of the study.
James believes the timing of migration explains this. Females appear to be the first to migrate, followed by the males.
“After a while, the males get the message. The females are there, or maybe it’s the heat. But they get the message, and they begin tracking up the mountains,” James said.
Bear Creek Mountain is just one spot in the Cascades where the coronis fritillary is found in mid- to late summer. Other areas are near Mount Rainier and Goat Rocks. On nine occasions, the coronis fritillary was also observed in the Olympics.
James said perhaps some males got overzealous in their search for females.
The males have a much more frenetic energy than the females, in constant movement until they are pale and their wings are in tatters. The few males that survive the journey back to the lower altitudes are the ones that mate and pass on their genes.
James doesn’t think it’s a great survival strategy.
“I think things are still in flux. I think this species is still evolving,” James said. The study will serve as a baseline for future researchers.
And for James, that discovery is part of the joy and excitement of biology.
Bear Creek Mountain
On a trip up to Bear Creek Mountain trail south of Rimrock Lake on a Saturday in late July, I was determined to get a photo of the coronis fritillary.
Not since I was a child had I been out butterfly hunting. It was a favorite pastime of my youth, but I did not get deep into identification. The knowledge of the butterfly enthusiast community, mostly self-taught people with no background in biology, has impressed me.
Bear Creek Mountain trail is within the Goat Rocks Wilderness Area, a stunning swath of alpine habitat named for its mountain goat population. The trailhead is a winding 16 miles from the intersection of Tieton Reservoir Road and U.S. Highway 12.
James has been up here for nine of the past 12 years for the study, but first came over 20 years ago, when he moved to the area from Australia to take a job with Washington State University’s Irrigated Agriculture Research and Extension Center in Prosser.
The road was a tad precarious for James’ Toyota Prius. I got out multiple times to chuck rather large rocks from the road. We parked short of the trailhead because of ruts at the top of a particularly bad hill.
The trailhead had some vehicles parked at it, a sight James didn’t see when he first started coming here. Joining us were multiple members of the Washington Butterfly Association. This time, James was wearing a T-shirt depicting famed lepidopterist Robert Michael Pyle with butterflies in his beard.
The trail gave passage to gorgeous mountain meadows, the flowers of which were a magnet for many hungry pollinators. The air was much cooler up here than in the Yakima Valley. Small streams fed oases of flowers. Small ponds were teeming with tadpoles.
James said that I should be heading up to the mountains more this time of year to escape the heat – just like the butterflies are doing. “They’re chasing the spring,” he said.
It was a fruitful trip: We saw 23 species in total, a number James said likely would have been higher if we’d come a few weeks later, at the peak of summer blooms.
There were plenty of coronis fritillaries, including a haggard-looking male I was able to get a snapshot of while it was nectaring on a flower. Soon, in late August, it will be one of many returning to the Yakima Valley to feed on the rabbitbrush in autumn bloom.
To join
David James will lead a Washington Butterfly Association field trip to observe the coronis fritillary at Cowiche Canyon Conservancy’s Snow Mountain Ranch on Sept. 13. Visit wabutterflyassoc.org or email david_james@wsu.edu for more information.
Questen Inghram is a WSU Murrow News Fellow based at the Yakima Herald-Republic, which originally published this article on Aug. 24, 2025.
