The Gunnison National Forest covers over 2000 square miles of Colorado's Western Slope. It consists of montane forest, scrubland and several rivers and their reservoirs. I recently traveled there and, despite frequent rains, managed to photograph a number of butterflies. I am a fish out of water when it comes to ID'ing butterflies on the western side of the Continental Divide. All of my field guides and prior experience are with eastern species. I've done the best I can with my ID's but it is possible I've missed one or two.
The first stop was Monarch Pass. Monarch Pass takes travelers across the Continental Divide. At its highest point the elevation is about 11,300 feet, but a tram ride will take you to the top of an adjacent peak to an elevation of about 12,000 feet. While riding the tram, I could see yellow and white butterflies which I presumed were probably Orange Sulphurs. When I got to the top, I walked the ridgeline a bit and found one of the white butterflies was actually a Rocky Mountain Parnassian (Parnassius smintheus). While Parnassians may look like Whites they are actually in the Swallowtail family.
A little further on and I photographed a small, brown butterfly. This, I'm told, is a Colorado Alpine (Erebius callius) despite the fact that is has a single, large eyespot(with two centers) on the forewing, rather than the traditional two smaller ones.
There didn't appear to be many more butterflies in this area so I made the trip back down to the Pass, where I walked the start of a trail that goes back up the ridge. The dominant butterfly in this area was a Comma that has been identified as a Zephyr Anglewing (Polygonia gracilis zephyrus) Zephyrs are a subspecies of Hoary Comma's best identified by the lack of a pale submarginal band on the underside of the wings.
There were Parnassians and Alpines on this lower trail as well, including the more traditional-looking Colorado Alpine
While photographing my umpteenth Zephyr another large butterfly landed on the same flower. I gasped and got off as many shots as I could but, sadly, the best I could do was this blurry shot of what I believe is a Milbert's Tortoiseshell (Aglais milberti)
The next stop was a place called Hermit's Rest, which was in the western part of the Forest, in Montrose County. Hermit's Rest is a scenic overlook off of Highway 92. It is at an elevation of about 8,500 feet. It includes a trail which winds its way down the slope to the Crystal Reservoir. The trail is about 3 miles long and drops in elevation about 1800 feet. The first butterfly I encountered along this trail appears to be a Riding's Satyr (Neominois ridingsii) Again, I was unable to get a good picture, which is a bit sickening because this appears to be a very uncommon butterfly.
Fortunately, Hermit's Rest was able to provide me with a number of other wonderful butterfly shots including this next butterfly, which I believe to be a female Blue Copper (Lycaena heteronea)
A bit farther down the trail I encountered what I believe is a Colorado Hairstreak (Hypaurotis crysalus)
A bit farther down and I found what I think is a Tailed Copper (Lycaena arota) Sadly, the area where the tails would be is obscured by a leaf.
The last butterfly I found at Hermit's rest is a Greater Fritillary genus Speyeria. At home in Nebraska I could reliably ID this as a Great Spangled Fritillary, but in Colorado, there are other choices. I'm leaning towards Aphrodite Fritillary (Speyeria aphrodite) but that is just my best guess.
The next day rained most of the day, so I didn't get a chance to go out hiking, but it dried up late afternoon so I could get in a walk around Gunnison. On a trail bordered by rangeland on one side, and the Gunnison airport on the other, I found this Clouded Sulphur (Colias philodice). While Clouded Sulphurs are not restricted to the West, or the mountains, they are less common around Nebraska, so I was glad to see it.
My last day in The Gunnison I set out for Dillion Pinnacles. Dillion Pinnacles is a geologic formation to the west of Gunnison. The formation consist of spires of breccia cemented by volcanic ash. A two mile trail winds up between the pinnacles above, and the Blue Mesa Reservoir below. Early on in the hike there was not much activity as the day was still cool from the lingering clouds of the previous days rains. But there was plenty of gorgeous scenery to enjoy and as it warmed up the butterflies started to come out. The first butterfly was, I believe, a Weidemeyer's Admiral (Limenitis weidemeyerii) The butterfly landed and spent some time sunning itself, so I got plenty of shots
As I hiked both the Pinnacles and Hermit's Rest I noticed many white butterflies flying along the trails. They never seemed to land so I couldn't get any good shots and I figured they were just Cabbage Whites so i didn't bother chasing them down. Well, one finally landed and it wasn't a Cabbage White at all. Instead, it was a Western White (Pontia occidentalis), one of the Checkered Whites.
The last butterfly I saw on my trip was also the smallest. It's small size made it difficult to focus on and I didn't get the best photo. I think it is an Alpine Blue (Plebejus lupini) though Euphilotes is a possibility as well.
So those were the butterflies I found in the Gunnison National Forest. Overall, I'd say it was a great trip. I'd definitely recommend it to anyone interested in western butterflies or just great scenery. Given a little better weather and some more knowledge of the area I think I could do even better if I ever get a chance to return.