25 butterflies were recorded flying in Montana in October in our iNaturalist sample; 1 of the top 50 are at their peak this month. The list is ranked by number of research-grade observations.
Top butterflies in October
Painted Lady
California Tortoiseshell
Variegated Fritillary
Milbert's Tortoiseshell
Mourning Cloak
Orange Sulphur
Hoary Comma
West Coast Lady
Small White
Clouded Sulphur
Common Checkered-Skipper
Green Comma
All butterflies flying in Montana in October
| # | Species | Scientific name | Family | Obs. | Peak in state |
|---|---|---|---|---|---|
| 1 | Painted Lady | Vanessa cardui | Brush-footed Butterflies | 17 | Jul (past peak) |
| 2 | California Tortoiseshell | Nymphalis californica | Brush-footed Butterflies | 17 | Jul (past peak) |
| 3 | Variegated Fritillary | Euptoieta claudia | Brush-footed Butterflies | 11 | Aug (past peak) |
| 4 | Milbert's Tortoiseshell | Aglais milberti | Brush-footed Butterflies | 11 | Jul (past peak) |
| 5 | Mourning Cloak | Nymphalis antiopa | Brush-footed Butterflies | 9 | Aug (past peak) |
| 6 | Orange Sulphur | Colias eurytheme | Whites, Yellows, and Sulphurs | 9 | Jul (past peak) |
| 7 | Hoary Comma | Polygonia gracilis | Brush-footed Butterflies | 8 | Aug (past peak) |
| 8 | West Coast Lady | Vanessa annabella | Brush-footed Butterflies | 7 | Sep (past peak) |
| 9 | Small White | Pieris rapae | Whites, Yellows, and Sulphurs | 7 | Jul (past peak) |
| 10 | Clouded Sulphur | Colias philodice | Whites, Yellows, and Sulphurs | 7 | Aug (past peak) |
| 11 | Common Checkered-Skipper | Burnsius communis | Skippers | 7 | Aug (past peak) |
| 12 | Green Comma | Polygonia faunus | Brush-footed Butterflies | 6 | May (past peak) |
| 13 | Western White | Pontia occidentalis | Whites, Yellows, and Sulphurs | 5 | Aug (past peak) |
| 14 | Red Admiral | Vanessa atalanta | Brush-footed Butterflies | 4 | Aug (past peak) |
| 15 | Mylitta Crescent | Phyciodes mylitta | Brush-footed Butterflies | 3 | Aug (past peak) |
| 16 | Purplish Copper | Tharsalea helloides | Gossamer-winged Butterflies | 3 | Sep (past peak) |
| 17 | Monarch | Danaus plexippus | Brush-footed Butterflies | 2 | Aug (past peak) |
| 18 | Two-tailed Swallowtail | Papilio multicaudata | Swallowtails and Parnassians | 2 | Jul (past peak) |
| 19 | Juba Skipper | Hesperia juba | Skippers | 2 | May (past peak) |
| 20 | Western Tiger Swallowtail | Papilio rutulus | Swallowtails and Parnassians | 1 | Jun (past peak) |
| 21 | Common Buckeye | Junonia coenia | Brush-footed Butterflies | 1 | Oct (peak) |
| 22 | Gray Hairstreak | Strymon melinus | Gossamer-winged Butterflies | 1 | Jul (past peak) |
| 23 | Satyr Comma | Polygonia satyrus | Brush-footed Butterflies | 1 | Aug (past peak) |
| 24 | Checkered White | Pontia protodice | Whites, Yellows, and Sulphurs | 1 | Jul (past peak) |
| 25 | Mormon Fritillary | Argynnis mormonia | Brush-footed Butterflies | 1 | Aug (past peak) |