Western Nebraska Spring Trip

After a week of watching the weather forecast, Monday Jen and I and the dog drove out to Chadron to try to locate as many of the spring flying butterfly species as we could before they vanished. We had been waiting for a couple of good days in succession and the forecast Sunday night was for conditions Tuesday and Wednesday to meet our expectations. We left with some trepidation as we had not visited the area for quite some time and in that interval wildfires in 2006 and 2012 had altered the landscape in large portions of the Pine Ridge substantially.

Tuesday we drove out to Monroe Canyon/Gilbert-Baker SWMA and found the area intact with butterflies awaiting our arrival. After spending several hours there we went a couple of miles east to check out Pants Butte and Sowbelly Canyon. Here the landscape was quite different with the remains of what were once majestic pine forests laying like skeletons across the horizon. But there were butterflies to be found, with most congregating on mud and flowering bushes. All in all it was a great day in the field — sunny, not too windy with temps in the mid 70s. In all we found 24 butterfly species, eight of which are new to my Big Year List. The eight new species were:

Afranius Duskywing (Erynnis afranius)

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In Nebraska the Afranius Duskywing has been found in the panhandle counties where it flies in two generations. It’s larvae feed on several wild legumes.

Anise Swallowtail (Papilio zelicaon)

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The Anise Swallowtail is another species restricted to panhandle counties where larvae feed on Musineon tenuifolium. There is a main spring flight followed by a smaller mid summer from mid June to mid July. We saw one in Sowbelly Canyon and one at Wildcat Hills SRA.

Checkered White (Pontia protodice)

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Checkered Whites can be found statewide flying in multiple generations. They were common on Tuesday. I netted several of them to see if they were possibly western whites but they did not appear to be. A post on those two species should be forthcoming.

Arrowhead Blue (Glaucopsyche piasus)

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This was the find of the day. One was found on mud (where butterflies often congregate to take in minerals and nutrients they do not get from nectar) in Sowbelly Canyon. The species can be found from late may into June. It has only been recorded from the canyon bottoms of Sioux County where its larvae feed on several legumes. Most years it goes unreported.

Melissa Blue (Plebejus melissa)

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Melissa Blues can be found statewide but are more common the farther west you go. They fly in multiple generations, with larvae feeding on legumes including alfalfa on occasion. The subspecies samuelis (The Karner Blue) is found in sporadic colonies from eastern Wisconsin to New York and is endangered. We saw perhaps a half dozen.

Anicia checkerspot (Euphydryas anicia)

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Anicia Checkerspots fly in one spring brood in Sioux, Dawes and Box Butte counties where they are occasionally abundant. This day we saw but one taking nectar from a chokecherry blossom. Colin Croft found them in abundance a day earlier near Agate Fossil Beds National Monument.

Ochre Ringlet (Coenonympha tullia ochracea)

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This uncommon butterfly flies from late May through June. Its larvae feed on various grasses. Sightings from outside western or northern regions of the state are rare. We sighted one in the Gilbert-Baker camping/picnic area.

Varuna Arctic (Oeneis uhleri varuna)

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This cryptically marked butterfly is an eastern prairie extension of a group of butterflies normally associated with higher elevations or colder climates. It flies in a single spring brood and in Nebraska has not been found east of the panhandle counties. It has a habit of landing in grasses where it becomes virtually invisible. We saw perhaps 20 on Tuesday without looking to hard.

Tuesday night we checked the local forecast which called for clouds to move in mid-day Wednesday. So Wednesday morning we left to check out Wildcat Hills SRA south of Scotts Bluff, arriving there about 11:00 am. The plants that were in flower and attracting butterflies in Sioux County were spent and attracting nothing at Wildcat Hills. Noting clouds gathering in the west we headed south to Kimball and west on I-80 to a unique spot a couple miles south of mile marker 1. We got there 5 minutes before the clouds and noted a half dozen blues and a skipper which all skillfully avoided identification and then went dormant when the clouds overtook us. After spending about an hour there waiting for the sun and butterflies to reappear we headed back east. After a quick stop at the I-80 East rest area (just west of Sidney) for an uneventful climb up rattlesnake hill we gave up for the day and headed home. So one awesome day and another not quite as awesome. Such is life.

The eight new species for the year bumps my year to date total to 37. One other note – The Celastrina (spring and summer azures) are in a constant state of revision. Superficially the spring azure in the Pine Ridge has a different appearance than specimens from the eastern part of the state and may at some point be “split” into separate species or subspecies. We did see one of these at Gilbert-Baker.

This trip pretty much wrapped up any last chances for spring flying species, most of which overwinter as pupae or late stage caterpillars. The “summer” flying species (fritillaries, viceroys, red spotted purples, wood nymphs, hairstreaks, and most skippers) flights should begin shortly if they haven’t already in southeastern Nebraska. It should be fun!