Butterflies Flying in Illinois in September (60 Species)

60 butterflies were recorded flying in Illinois in September in our iNaturalist sample; 8 of the top 50 are at their peak this month. The list is ranked by number of research-grade observations.

Mar Apr May Jun Jul Aug Sep Oct Nov

Top butterflies in September

Monarch4,653 obs.

Painted Lady1,799 obs.

Common Buckeye1,516 obs.

Fiery Skipper1,299 obs.

Silver-spotted Skipper1,061 obs.

Black Swallowtail1,059 obs.

Pearl Crescent1,047 obs.

Small White969 obs.

Orange Sulphur903 obs.

Peck's Skipper865 obs.

Eastern Tailed-Blue718 obs.

Viceroy646 obs.

All butterflies flying in Illinois in September

#	Species	Scientific name	Family	Obs.	Peak in state
1	Monarch	Danaus plexippus	Brush-footed Butterflies	4,653	Aug (past peak)
2	Painted Lady	Vanessa cardui	Brush-footed Butterflies	1,799	Sep (peak)
3	Common Buckeye	Junonia coenia	Brush-footed Butterflies	1,516	Aug (past peak)
4	Fiery Skipper	Hylephila phyleus	Skippers	1,299	Sep (peak)
5	Silver-spotted Skipper	Epargyreus clarus	Skippers	1,061	Jul (past peak)
6	Black Swallowtail	Papilio polyxenes	Swallowtails and Parnassians	1,059	Jul (past peak)
7	Pearl Crescent	Phyciodes tharos	Brush-footed Butterflies	1,047	Jul (past peak)
8	Small White	Pieris rapae	Whites, Yellows, and Sulphurs	969	Jul (past peak)
9	Orange Sulphur	Colias eurytheme	Whites, Yellows, and Sulphurs	903	Sep (peak)
10	Peck's Skipper	Polites peckius	Skippers	865	Aug (past peak)
11	Eastern Tailed-Blue	Everes comyntas	Gossamer-winged Butterflies	718	Jul (past peak)
12	Viceroy	Limenitis archippus	Brush-footed Butterflies	646	Aug (past peak)
13	Variegated Fritillary	Euptoieta claudia	Brush-footed Butterflies	378	Sep (peak)
14	Huron Skipper	Atalopedes huron	Skippers	337	Sep (peak)
15	Eastern Tiger Swallowtail	Papilio glaucus	Swallowtails and Parnassians	320	Aug (past peak)
16	Red Admiral	Vanessa atalanta	Brush-footed Butterflies	285	Jul (past peak)
17	Eastern Comma	Polygonia comma	Brush-footed Butterflies	258	Jul (past peak)
18	Hackberry Emperor	Asterocampa celtis	Brush-footed Butterflies	247	Aug (past peak)
19	Tawny-edged Skipper	Polites themistocles	Skippers	208	Aug (past peak)
20	Red-spotted Admiral	Limenitis arthemis	Brush-footed Butterflies	192	Aug (past peak)
21	Question Mark	Polygonia interrogationis	Brush-footed Butterflies	190	Jul (past peak)
22	Pipevine Swallowtail	Battus philenor	Swallowtails and Parnassians	185	Jul (past peak)
23	Gray Hairstreak	Strymon melinus	Gossamer-winged Butterflies	177	Sep (peak)
24	Cloudless Sulphur	Phoebis sennae	Whites, Yellows, and Sulphurs	170	Aug (past peak)
25	Clouded Sulphur	Colias philodice	Whites, Yellows, and Sulphurs	156	Sep (peak)
26	Wild Indigo Duskywing	Erynnis baptisiae	Skippers	146	Aug (past peak)
27	Summer Azure	Celastrina neglecta	Gossamer-winged Butterflies	138	Jul (past peak)
28	Great Spangled Fritillary	Argynnis cybele	Brush-footed Butterflies	121	Jun (past peak)
29	American Snout	Libytheana carinenta	Brush-footed Butterflies	114	Jul (past peak)
30	Least Skipper	Ancyloxypha numitor	Skippers	104	Aug (past peak)
31	Spicebush Swallowtail	Papilio troilus	Swallowtails and Parnassians	91	Jul (past peak)
32	American Lady	Vanessa virginiensis	Brush-footed Butterflies	90	May (past peak)
33	Mourning Cloak	Nymphalis antiopa	Brush-footed Butterflies	86	Jun (past peak)
34	Eastern Giant Swallowtail	Heraclides cresphontes	Swallowtails and Parnassians	79	Jul (past peak)
35	Zabulon Skipper	Lon zabulon	Skippers	69	Aug (past peak)
36	Tawny Emperor	Asterocampa clyton	Brush-footed Butterflies	67	Aug (past peak)
37	Northern Pearly-eye	Lethe anthedon	Brush-footed Butterflies	65	Jul (past peak)
38	Little Yellow	Eurema lisa	Whites, Yellows, and Sulphurs	61	Jul (past peak)
39	Bronze Copper	Tharsalea hyllus	Gossamer-winged Butterflies	54	Aug (past peak)
40	Common Checkered-Skipper	Burnsius communis	Skippers	45	Oct (rising)
41	Dainty Sulphur	Nathalis iole	Whites, Yellows, and Sulphurs	42	Oct (rising)
42	Meadow Fritillary	Boloria bellona	Brush-footed Butterflies	42	Jun (past peak)
43	Ocola Skipper	Panoquina ocola	Skippers	41	Oct (rising)
44	Dun Skipper	Euphyes vestris	Skippers	33	Jun (past peak)
45	Eastern Gemmed-Satyr	Cyllopsis gemma	Brush-footed Butterflies	28	Sep (peak)
46	Gray Comma	Polygonia progne	Brush-footed Butterflies	27	Jul (past peak)
47	Silvery Checkerspot	Chlosyne nycteis	Brush-footed Butterflies	24	Jul (past peak)
48	Harvester	Feniseca tarquinius	Gossamer-winged Butterflies	23	Aug (past peak)
49	Southern Dogface	Zerene cesonia	Whites, Yellows, and Sulphurs	21	Aug (past peak)
50	Red-banded Hairstreak	Calycopis cecrops	Gossamer-winged Butterflies	18	Jul (past peak)