On April 11, 2017, the first butterfly of the year was spotted inside the Koyuk IRA building in Alaska. The observer wonders if it is a tortoiseshell butterfly. LEO suggests that it resembles the Milbert's Tortoiseshell and shares the observation with the UAF Cooperative Extension Service Forest Health. A member comments that there are two photos of butterflies, one being a Milbert's Tortoiseshell and the other a Compton Tortoiseshell. Resources for identifying the butterflies are provided, including Butterflies and Moths of North America, Butterflies of America, Wikimedia Commons, and iNaturalist.

Observation: First butterfly of the year spotted inside the Koyuk IRA building on April 11, 2017. Spring is approaching but it still seems too cold for this little guy. I am wondering, is it a tortoiseshell butterfly?

LEO says: The butterfly appears to resemble the Milbert's Tortoiseshell Aglais milberti... This observation has been shared with the UAF Cooperative Extension Service (Forest Health).

Member Comment Derek Sykes writes: "There are two photos of butterflies. One with the word 'GOLD' above it - that butterfly is a Milbert's Tortoiseshell. The other is a Compton Tortoiseshell.

Resources:

Butterflies and Moths of North America – Range: "Southeast Alaska and Canada south in the mountains to Montana and Wyoming; east across southern Canada and the northern United States to New England; south to North Carolina and Missouri. Rare migrants to Newfoundland, Nebraska, and Florida. This species is also found in temperate Eurasia."

Butterflies of America – Nymphalis l-album j-album (Boisduval & Le Conte, [1835]). Compton Tortoiseshell Life Adults photo collection.

Wikimedia Commons – Compton Tortoiseshell (Nymphalis vaualbum), linked to a photo for insect identification comparison. Source: WCs, the free media repository

iNaturalist – "The adult female will lay her eggs in a clump on the host plant. Once the eggs hatch the caterpillars will feed together until they pupate. There is one brood that flies from July to November."