Crescent Lake/Ash Hollow Trip – 18 species, 6 new

Jen and I decided to visit the Crescent Lake area north of Oshkosh in hopes of crossing Lupine Blues, Giant Yucca and Uncas Skippers off my big year list. To cut two hours off the three and one half hour trip we traveled as far as Ogallala the night before. That also enabled us to arrive a little earlier and avoid some of the mid 90’s heat predicted for later in the day. While it used to be a regular stop for me I had not been to Crescent Lake since 2002. So it was with much anticipation we began the 28 mile drive north out of Oshkosh into the sandhills and Crescent Lake. I had been forewarned of a high water situation in the area and about half way to the Refuge there was a large sign next to the road warning of water across the road and that only four wheel drive vehicles should proceed. Duly warned we proceeded. I guess once you get to a certain age you should realize that nothing is forever and things change but I was not prepared for what I saw upon arriving at Crescent Lake. Somewhere in the 18 years since I had last visited the area had burned. What used to be yucca covered hills were now nearly devoid of that plant. So no yucca, no Giant Yucca Skippers.

The low spots in the road in the area had been raised (at considerable expense I would think) by up to a foot for one lane traffic. We pulled off at Island Lake to take this pic with just the roof of a picnic shelter (or something) just visible above the water.

So having struck out on Giant Yucca Skippers we started working our way back to Oshkosh stopping first at NE Game and Parks Crescent Lake State Wildlife Management Area. Following the road to the boat dock we drove through a prairie dog town and over one burrow some wise guy had dug in the middle of the road. He/she saw us coming and safely ducked to avoid any interaction with us. Arriving at the boat dock we noticed there were some willows nearby that had attracted some Viceroys (Limenitis archippus) and a Mourning Cloak (Nymphalis antiopa) – the larvae of which both feed on willows. While not rare, both of them were new for my Big Year species count.

Both species are found statewide with the larvae feeding mainly on willows. Viceroys have two generations and overwinter as early instar larvae while Mourning Cloaks overwinter as adults. When found, Mourning Cloak larvae often feed in a group.

Heading back to Oshkosh we passed a roadside mud puddle and stopped to check it out. Some Checkered Whites were flying and we captured a couple of males to pin up and see if they were Western Whites (P. occidentalis) – to be determined. Also quite a few other smaller butterflies. Along the roadside there was an abundant supply of yellow flowers (Stiff Greenthread – Thelesperma filifolium I think) upon which we were excited to find a Ruddy Copper (Lycaena rubida). I hadn’t seen one of these in years. The larvae feed on winged dock (Rumex venosus) which is present at almost any disturbed location in the panhandle. I didn’t see anything special about the site so I think this butterfly is widely (but sparsely) distributed across the state’s western counties. This butterfly’s flight period is restricted to a single brood largely coinciding with the month of June.

Ruddy Copper, picture from
Winged Dock – photo from plants and animals of northeast colorado
Distribution of Ruddy Copper in Nebraska

So we made our way back to Oshkosh and then back east to Ash Hollow State Historical Park at the west end of Lake McConaughy. We checked for any activity on the hillsides in the park and found several Dainty Sulfurs (Nathalis iole), new for the Big Year, but little else. These small sulfurs are in the group of regular visitors from the south which cannot survive Nebraska winters but repopulate the state annually. Unlike most sulfurs the larvae do not feed on legumes but rather on various composites including the greenthreads that were blooming in the area. Leaving the historical park we took the road just north of the park back to the east. There we found one yellow flowering plant which we stopped to investigate. There was a beat up Pearl Crescent and Orange Sulphur there so we got ready to move on. Then we saw some movement on some knee high Yellow Clover next to it. Taking a closer look we found about a dozen Juniper Hairstreaks and then a Marine Blue (Leptotes marina). The Marine Blue is an uncommon southern stray. Probably overlooked due to its small size years often pass between sightings. Larvae feed on legumes so it is possible they breed here but once again they cannot survive the winter. Records for both species span the state.

Having time for one last stop we road hunted for a couple of miles and found some milkweeds in bloom south of Lewellen. There we found numerous butterflies including Least Skippers and a Buckeye (Junonia coenia). Same song and dance for the Buckeye – regular southern visitor not overwintering. Found statewide it likely breeds here with larvae feeding on various plaintains, figworts and vervains.

With the temps and the wind cranking up we headed back to Elm Creek. After striking out on our three target species (Lupine Blues, Strecker’s Giant and Uncas Skippers) we ended up identifying 18 species, 6 of which were new for the “Big Year”. They were: Common Checkered Skipper, Common Sootywing, Least Skipper, unknown skipper, Black Swallowtail, Checkered or Western White (tbd), Alfalfa Butterfly, Dainty Sulphur, Ruddy Copper, Juniper Hairstreak, Marine Blue, Reakirt’s Blue, Variegated Fritillary, Pearl Crescent, Mourning Cloak, Painted Lady, Red Admiral, Viceroy and Buckeye.

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