Updated: Aug 3, 2021
The Illinois River valley in Josephine County may well have more species of white butterflies in early spring than any other part of Oregon. The list includes mustard white, western white, gray marble, California marble, Sara's orangetip, Julia's orangetip, and the somewhat elusive spring white (Pontia sisymbrii). Wait. What? Julia's Orangetip? In case you haven't heard the news, the white butterflies with orange forewing tips in most of Oregon are now considered to be Julia's Orangetip, which is a truly northwestern butterfly. Sara's Orangetip is now essentially a California butterfly that just creeps over the border into southern Oregon. But I digress, that's a topic for another day. The matter at hand is another of the whites of spring, namely the Spring White, and it shows up in April down in SW Oregon. It was to search for that bug that I made the three hour drive down to Selma, Oregon this past week.
The Spring White can look very similar to the Western White, and it's necessary to closely scrutinize the ventral hind wing to look for a pale double track of lightness across the dark bars on the hind wing--that's one of the key identification characters for this species. Unfortunately, I had not sufficiently scrutinized a photo I had mistakenly identified as a Spring White some years back, and it briefly appeared on this website. The authorities were notified of the imposter, and it was removed to an undisclosed location. It wasn't a great photo, but it was surely better than nothing, I had thought. Oops--not better than nothing. Hello, square one.
With a rainy spell holding forth in Lane County, it was very appealing to throw my tent in my car and dash down to sunny SW Oregon in hopes of filling one of the holes in my photo collection. Mind you, "throwing my tent in the car" involves hours of packing and preparing for every possible eventuality, but I have been able to hone that process down over time to less than half a day.
I hadn't been down the Illinois River Road in many years and I was eager to see how it had changed with recovery from old wildfires and from more recent ones. The weather forecast was for partly cloudy and upper 60's for a couple of days, so I threw the dice, and hit the road.
In spite of cloudy mornings, the Illinois River valley did not disappoint. White butterflies were in good numbers whenever the sun was out in full. Since I was there in pursuit of photos, and decked out with two cameras and binoculars, I did not carry my net. Which meant most of those fast-flying white butterflies that whizzed by me landed in the "white sp." category. Many of them looked like the pure white dorsal pattern of Mustard (Margined) Whites, but I couldn't be sure enough to make the call.
What I could be sure of were the scores of mostly haggard California Tortoiseshells along the river, and several species of blues taking their mineral supplements at the roadside seeps.
Unlike my past visits to this area, the muddy spots at the road's edge were much more popular for puddling butterflies than the sandy spots along the river. A very fresh Indra Swallowtail repeatedly begged me to take it's photo, landing at my feet with its wings nicely composed. I obliged.
This was just after one of my cameras was put out of commission for the day by "some guy" who got a little too excited at seeing a new species, and stumbled while kneeling down for a photo. His right hand shot forward to steady himself, but alas, there was a camera in that hand, and there was this large object in the path of his movement called Earth. The UV filter on the lens was shattered and bent so that it could not be removed by hand, making the camera temporarily unusable. I cursed that guy for his klutziness, noting that while he looked a lot like me, it couldn't be me because I'm not that much of a klutz. The butterfly that inspired his dance of ignominy turned out to be a Dotted Blue (Euphilotes enoptes).
In the cool, cloudy mornings both days, I kept reminding myself that I didn't need to see a lot of butterfly species--I only needed to see one butterfly (as long as that one was a Spring White). That's how I persuaded myself not to turn around and head home when it started raining the second morning. That "mantra" appeared to gain power with each repetition, and the sun did emerge in the afternoon. Surprisingly, I saw a total of 18 species that day. It has often been said of affirmations that the brain only picks up on the positive part of the statement (e.g., "see a lot of butterfly species"). It's a small sample size, so I won't draw any conclusions.
The majority of the butterflies were at or close to sources of moisture, either along the river's edge, or at roadside seeps, including Acmon Blues, Silvery Blues, Spring Azures, Propertius Duskywings, and Common Checkered-Skippers. Mylitta's Crescents, California Tortoiseshells and Common Ringlets were patrolling in drier spots, while Pale Swallowtails, Mustard Whites, California Marbles, unidentified whites, and a lone Orange Sulphur were rapidly crossing through the area.
I was pleasantly surprised that in the nearly 20 years since I'd visited this area, it didn't seem to have changed character very much. The areas that had burned all those years ago may have burned again, but regeneration was going on all around, and wildflowers were in full bloom along the road.
The tally for the two days was 24 species, which for mid-April is respectable. Its not quite the 35-species-in-mid-April-on-the-lower-Klamath-River kind of respectable that Andy Warren once found, but its respectable nevertheless. In reviewing my notes on flight times for the Spring White in southern Oregon, it looked like it might be better odds to go a week or two earlier in April next year, at the end of a week or two sunny weather. If you've had any Pontia sisymbrii sightings in Oregon this year, I'd love to hear from you.
Below is an accounting of what I observed and identified over the two days.