On Monday, June 20, I was invited by wildlife biologist Joe Doerr to join a group of wildlife biologists and botanists from the Willamette National Forest on a trip to Bristow Prairie. The goals were generally to familiarize everyone with butterfly species in our area and specifically to search for the Sierra Nevada blue, also called gray blue or arrowhead arctic blue (Agriades or Plebejus podarce—so many names!). Last year I discovered it at Reynolds Ridge (see A Day Full of Surprises) a year after it was first discovered there by Forest Service biologists surveying for it in southern Oregon. I mentioned it to Lori Humphreys who promptly went out and discovered it for the first time in Lane County in the little wetland off of the High Divide trail just north of Bristow Prairie. I saw it the same spot a few days later (see NARGS Campout Day 1: Bristow Prairie). This being the northernmost site so far, it seemed like the nearest place to take everyone to see it. Along with the forest service employees, our group included Lori, Dana Ross, Gary Pearson, and Rick Ahrens, expert naturalists and also non-agency “volunteers”.
Our day began at the Middle Fork District office with a short slide show primer by Dana on the Sierra Nevada blue and our more common local butterflies. We then caravaned up to Bristow Prairie. The road was passable, but I’ve never seen as many trees down along this route. I was glad I wasn’t driving! We parked at the north end of Bristow Prairie where I usually park when exploring the meadows. There were enough botanists there that I had to point out the adorable, tiny least moonwort (Botrychium simplex), still happily occupying the wet edge of the gravel road, displaying miniature grape-like fruits to anyone willing to get down on their hands and knees.
Although we were planning to head to the small wetland where Lori and I had seen the blues, I really thought we should also check out the much larger wetland by the shallow lake on the southwest end of the prairie. Technically, that’s in the Umpqua National Forest, as the ridge of the Calapooyas marks the dividing line between the two national forests. It’s also in Douglas County, as the county line runs through the middle of the lake. Since we didn’t have any folks from the Umpqua NF, I seemed to be the only one who was familiar with the lake, so I led the way across the meadow.
While everyone else was netting moths, bees, and a few butterflies to identify, I headed rather impatiently over toward the lake, not wanting to run out of time exploring this most impacted and least interesting part of the area. I went to talk to Ryan Murdoff, a Middle Fork district botanist. There, right at our feet, was a large patch of dusky horkelia (Horkelia fusca). The very first time I ever tried (unsuccessfully due to a flat tire) to get up to Bristow Prairie, it was with a group looking for this plant in Lane County. Since then, Sabine Dutoit and I had found it on the Douglas County part of the trail, but we had never been able to find any on the Lane County side. How funny to finally locate it on the Lane County side while looking for something entirely different!
There were far more clouds than there had been in the valley, so I was a bit discouraged about having a good butterfly day. After seeing it in the little wetland last year, I’d looked for them by the lake, but a large cloud hovering above kept all the butterflies out of sight, and I didn’t have time to wait for the sun. I didn’t want a repeat of that. Eventually we made it down to the wetland by the lake. On the way down, we spotted several western meadow (AKA Pacific) fritillaries waiting patiently for the sun to return. I also saw an arctic skipper trying to warm up. I don’t usually have so much luck seeing still butterflies. Thankfully, after a while, the sun appeared, and the butterflies became active.
Everyone was looking for the little Sierra Nevada blues. We could see loads of the white pom-pom flowers of bistort (Bistorta bistortoides), seemingly their favorite nectar plants, as well as the leaves and a few remaining flowers of mountain shooting star (Dodecatheon jeffreyi), their caterpillar host plant. Satisying all their needs and as close as this was to the other wetland, they just had to be there. At last, the holler everyone was waiting for. Alice Smith, botanist for the Sweet Home district, got the gold star for spotting the first of our target species. It was netted and slipped into a glass jar for viewing. For most of the participants, it was their first time seeing this lovely blue. After it was released, it was very cooperative about allowing me to photograph it. The cool temperatures and the passing clouds turned out to advantageous for photographing butterflies, even if it made it a little harder to locate them.
After lunch, we headed across Bristow Prairie to the north wetland. We went past the gorgeous rock garden rather quickly, both because we wanted to make sure we had time to look for the blues at the wetland and because the mosquitoes were dreadful. Quite a few participants found their butterfly nets doubled well as mosquito netting (why did I forget to photograph that?!). I could barely take a photo without dozens of them landing on me. This was my 15th trip to the Bristow Prairie area, and I don’t remember ever noticing many mosquitoes. Luckily, they don’t seem to cause me to itch much, so once we got out into the open where the breeze blew them away, I forgot all about them. On the way back, some of us climbed up the rocky slope to look at all the beautiful flowers, and it was actually rather windy, making it much more relaxing. The butterflies were staying out of the wind along the trail, so the folks more interested in butterflies than flowers were enjoying watching Callippe fritillaries, but they had to contend with the hordes of mosquitoes.
While some people had to leave early, many made it to the north wetland and were pleased to find more Sierra Nevada blues. I photographed at least 3 different individuals, and Gary Pearson thought there were as many as 10. The better count than at the lake may have been due to the receding clouds and warmer afternoon temperatures, or because they were hatching out earlier here, or it may be there was actually a larger population here in spite of the much smaller size of the habitat. Whatever the reason, we were all happy to see them, as well as the many other butterflies. I thought it was a very successful day, and I enjoyed getting together and meeting other knowledgeable butterfly and flower lovers.
BUTTERFLIES OBSERVED: 25 species
list compiled by lepidopterists Dana Ross & Gary Pearson
Pale Tiger Swallowtail (Papilio eurymedon) – fairly common throughout area.
Western Tiger Swallowtail (Papilio rutulus) – uncommon; common at lower elevations.
Anise Swallowtail (Papilio zelicaon) – ONE observed at steep rock garden hillside.
Clodius Parnassian (Parnassius clodius) – fairly common in meadows.
Margined White (Pieris marginalis) – a few observed in meadows.
Sara Orange Tip (Anthocharis sara) – fairly common and in fresh condition.
Orange Sulphur (Colias eurytheme) – one observed in meadow.
California Sister (Adelpha californica) – ONE observed at far Sierra Blue meadow.
Hoffmann’s Checkerspot (Chlosyne hoffmanni) – several observed in meadow & near parking area.
Monarch (Danaus plexippus) – ONE observed at first/NEW Sierra Blue pond location.
Snowberry Checkerspot (Euphydryas colon) – generally uncommon throughout area.
Edith’s Checkerspot (Euphydryas editha) – TWO singletons; at rock garden & meadow near parking area.
Pacific Fritillary (Boloria epithore) – fairly common in meadows thoroughout area.
Callippe Fritillary (Speyeria callippe) – locally common at steep rock garden hillside.
Red Admiral (Vanessa atalanta) – ONE observed in flight over far meadow.
West Coast Lady (Vanessa annabella) – ONE observed at steep rock garden hillside.
Silvery Blue (Glaucopsyche lygdamus) – fairly common throughout meadows.
Boisduval’s Blue (Plebejus icarioides) – generally uncommon; fresh; near lupine.
Sierra Blue (Plebejus podarce klamathensis) – ONE male observed at first (NEW) location above pond; about 10 observed at far meadow location (2015 Lori Humphreys discovery site).
Greenish Blue (Plebejus saepiolus) – fairly common; vicinity of clover; parking area and meadows.
Cedar Hairstreak (Callophrys gryneus) – TWO observed; one at rock garden & one at far meadow site.
Field Crescent (Phyciodes pulchella) – a few fresh males observed at second, far meadow location.
Arctic Skipper (Carterocephalus palaemon) – TWO observed; one at in wetland near pong, one caught/released at second, far meadow location.
Western Branded Skipper (Hesperia colorado) – ONE observed in meadow above parking area.
Juba Skipper (Hesperia juba) – ONE observed in meadow above parking area.