Updated: May 7, 2020
It isn't often that I get to write about actually finding and photographing an Oregon butterfly species that I haven't photographed before. It is exciting to be able to do so today! Today's find is a species that I have searched for multiple times over a 15 year period, and until today, had no photos to show for my efforts. The Hoary Elfin is a small, fast-flying obscure (hard to spot) butterfly that lives in and around patches of Kinnikinnick (Arctostaphylos uva-ursi). Some people call it bearberry, but I grew up knowing this plant as Kinnikinnick, and we had it growing in our front yard as a ground cover, under oak and birch trees. The "hoary" in this Elfin's name sometimes gets giggles from younger folk, but here it refers to the frosted look of the ventral hindwing, as in "hoarfrost."
Hoary Elfin is widespread, but locally common in the northeast quadrant of Oregon, where Kinnikinnick grows, especially above 4,000 feet. West of the Cascade Range, it's a very different story. On the west side, it occurs in small, isolated colonies separated from each other by long distances. These westside remnant populations are vulnerable, and any one of them could disappear from an especially harsh weather event, an inopportune wildfire, or a significant human disturbance.
The Hoary Elfin flies only from late April to early June, with higher elevation populations flying in the later part of that period. These western Oregon populations fly lower and earlier and thus have to contend with variable weather conditions of spring. Today, I found a few fresh individuals flying under cloudy skies with relatively warm temperatures (70°F).
Like many very small butterflies, it is often easier to spot them by looking for their shadows on the ground, which are larger than the butterfly itself. Today however, there were no shadows at all, since the sun was not shining! So it was lucky that I spotted a few of them in flight, amongst the Kinnikinnick and joined by several foraging bumble bees. Success in finding and photographing this handsome little butterfly didn't require braving the elements, searching for days, slogging through treacherous terrain, fighting off noxious pests or anything like that. It just required knowing where and when to search.
The vulnerability of these west-side colonies is why I'm not sharing details of the location where I found the Hoary Elfin today. These isolated populations of Hoary Elfin include some colonies along the coast and the Elfins in those colonies have been identified as a sub-species, Callophrys polios maritima. It remains to be seen whether other westside but inland colonies will be considered as the same subspecies. Many of these remnant colonies are quite small, and considered threatened and vulnerable, even though the species as a whole is widespread, especially in the eastern US and Canada. Our west-side populations are like genetic outposts at the edge of the species' range, which can harbor valuable genetic variation for the resilience of the species as a whole.
I hope that we can conserve these outpost populations of the Hoary Elfin, while also discovering more of these westsside populations. Knowing that they can occur in widely separated locations with kinnikinnick from the coast to the foothills of the Cascades should inspire butterfly enthusiasts and scientists to search more widely in healthy patches of Kinnikinnick.
There are now just 10 described species of butterflies that are thought to breed in Oregon that I haven't yet photographed: Oregon Swallowtail, Checkered White, Spring White, American Copper, Goldhunter's Hairstreak, Gillett's Checkerspot, Compton Tortoiseshell, Common Sootywing, Garita Skipperling, and Nevada Skipper. With luck, and good information from helpful colleagues, I hope to pick up a couple more of those this year, especially those that are relatively widespread and common!