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Loving Leona

Updated: Aug 29, 2022

Leona's Blue (Philotiella leona) is Oregon's only known endemic butterfly. It has been found only in the pumice flats created by the explosion of Mt. Mazama, which also created our famous and beloved Crater Lake. Viewed at the scale of states, countries or the planet, this butterfly is extremely rare and very localized. In 2010, a group of scientists and conservation organizations petitioned the US Fish and Wildlife Service to list the species as threatened or endangered under the ESA. Such a listing would have put protective regulations in place to help avoid impacts to the butterfly and it's habitat.

The species entire population was originally estimated to be just 1,000-2,000 individuals, living within a 6 to 12 square mile area of dry pumice desert. Later estimates indicated the the population might be much larger, perhaps as many as 20,000. Yet, further searches did not locate any other populations--that 6-12 square mile patch of desert is all Leona has. The federal government declined to take action to protect it under the Endangered Species Act (ESA). In 2015, the Fish and Wildlife Service responded to the ESA listing petition by saying "After a review of the best available scientific and commercial information, we find that listing Leona’s little blue butterfly is not warranted at this time."

In early July (2022), I went back to visit the pumice desert for the third time over many years, hoping that the late spring had pushed the Leona's Blue flight period back a week or two. Normally it's peak flight is in late June, but I was headed there on July 8, with my fingers crossed.

The original location that I learned about after Harold Rice found this butterfly was near Sand Creek, along Hwy 97 in Klamath County. The first time I visited the site, there were many Leona's Blues there in a patch of pumice flat with many Spurry Buckwheat (Eriogonum spergulinum var. reddingianum) plants and many Sulphur-flowered Buckwheat (Eriogonum umbellatum) plants. The diminutive and pale pink Spurry Buckwheat is greatly overshadowed by its bigger, bolder and sympatric cousin Sulphur-flowered Buckwheat (see photo below), which is a favored nectar source for Leona's Blue.

Photo of Sand Creek pumice flats
Mount Scott (Crater Lake) from the pumice flats east of Crater Lake. Sulphur-flowered Buckwheat in foreground.

On this trip, I went back to check on that original location, and was a bit alarmed by what I saw. I found it ravaged by a logging operation, which left huge piles of cut logs, and significant ground disturbance that dominated the landscape. Driving through the logged area, which was much larger than the area where I originally saw Leona, I saw no butterflies of any species. It appeared that the logging operations had damaged a big chunk of the Leona Blue's habitat. Further investigation is needed to verify this.

Close up photo of Leona's Blue on Spurry Buckwheat
Leona's Blue on its host plant, Spurry Buckwheat

Further west and south from the "original" site, I did find some Leona's Blues, and happily, several of them were in very fresh condition. To really appreciate them, you either need to get really close (if your near vision is good), use binoculars, or both.

Seeing that habitat disturbance, and seeing how few Leona's blues I could find in the area over several hours of searching caused me some concern. I don't know when the last survey for Leona's Blue was conducted, or how much of its known range has been impacted by logging and other human activities. The part of Oregon that contains this pumice desert habitat has been so dry for so long now, that the federal government has designated it as an area of extreme drought. In the long run, these extreme drought conditions may adversely affect both the butterfly and the plants it depends on.

Photo of Leona's Blue butterfly
Leona's Blue (Philotiella leona) on Eriogonum umbellatum (Sulphur-flowered Buckwheat)

Leona's Blue is so small that when Andy Warren first gave me guidance on finding it, he said "look for the shadow of the butterfly, not the butterfly. The shadows are bigger and easier to see." The tiny host plant, Spurry Buckwheat, is just as easily overlooked, even though it is more widespread than Leona's Blue. The small range of this butterfly, together with its short flight season and small size allowed it to be overlooked until 1995, when Harold Rice and his wife Leona discovered it.

Photo of Leona's Blue butterfly
Leona's Blue (Philotiella leona) on Eriogonum umbellatum (Sulphur-flowered Buckwheat)

In several hours of searching, I found a total of 8 Leona's Blues. They were noticeably smaller than the Summit Blues (Euphilotes glaucon) and Lupine Blues (Icaricia lupini) in the area, and their flight pattern was distinctive. They had a slower, more fluttery flight pattern than the other blues, which made it easier to spot them. I'd previously seen that the late, wet spring had depressed numbers of many species in Oregon this year, so I can't make any conclusion about the state of the population based on what I saw on this single site visit.

Photo of mating pair of Summit Blues
Mating pair of Summit Blues (Euphilotes glaucon) on a yellow flowering buckwheat

Leona's Blue is a butterfly that most Oregonians have never heard of, let alone ever seen. It is vulnerable because its habitat is so very limited and its range is so small, but also because few people even know that it's there. That means there are few who would stand up for protecting it, if it's population was in crisis. A large wildfire, or more extensive land disturbance in that area could be devastating to this population. All of which is to say that I believe we need to take care of this lovely little butterfly, which is a tiny flying symbol of one of our best known natural attractions, Crater Lake. We need to take care of its habitat, and the web of life that depends on that habitat. It's part of Oregon.

I'm wondering if it's time to conduct new surveys, both to check on the current status of the butterfly's population, and also to assess the current extent of healthy and suitable habitat. In writing this post, I contacted the Xerces Society, who had coordinated the ESA listing petition for Leona's Blue back in 2010. I asked whether any on-going monitoring is happening, and if so, who is leading that effort. I have yet to hear back from them, but I hope I do. This butterfly may not survive on its own. Even though you may never have seen one, it is part of an intricate and interconnected ecosystem that we all depend on, which took millions of years to evolve. That's partly why the existence of Leona's Blue, for me, is not trivial. I care about Leona's Blue and its habitat, and I hope you do too.

Thank you Harold Rice, for all the great contributions you made to our knowledge of Oregon butterflies during your lifetime. I hope we who are still here can help conserve all that you found.

In several hours of searching in the pumice flats near Sand Creek, I found 9 species of butterflies:

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