Peak Count Data for Butterflies at Fermilab
Sorted by Common Name
A list of butterflies Tom Peterson observed on the 6800 acre Fermilab site, 40 miles west of Chicago, Illinois.
Each time Tom went butterfly watching, he counted the number he saw per hour of each species. At the end of each summer, he made a chart with the day on which he saw the maximum number of each species ("date recorded" below) and the number he saw ("peak count per hour") for that species.

Butterfly Data - Peak Count by Scientific Name - by Number Found for 1999 - 2000 - 2001 - 2002 - 2003

Butterfly SpeciesDate RecordedPeak Count
per hour
for 1999   for 2000   for 2001   for 2002   for 2003  

Acadian Hairstreak
Satyrium acadica
06/23/19991  
07/08/20011  
07/03/20021  
07/09/20031  
American Lady
Vanessa virginiensis
06/07/20001  
05/17/20015  
05/03/20022  
04/25/20031  
American Snout
Libytheana carinenta
07/21/20001  
09/29/20011  
Banded Hairstreak
Satyrium calanus
06/21/19995  
06/22/20002  
06/25/20015  
07/14/20021  
07/14/20034  
Black Dash
Euphyes conspicua
07/06/19992  
07/07/20002  
07/13/20012  
07/12/20022  
07/16/20031  
Black Swallowtail
Papilio polyxenes
08/17/19992  
08/30/20002  
08/04/200112  
07/20/20022  
06/25/20033  
Bronze Copper
Lycaena hyllus
06/08/1999,
08/16/1999
3  
08/07/20003  
08/03/20015  
09/11/20021  
07/29/20033  
Cabbage White
Pieris rapae
06/21/199930  
08/11/200020+ +
08/04/200130+ +
08/25/200220+ +
09/06/200312  
Checkered White
Pontia protodice
09/05/20011  
Clouded Sulphur*
Colias philodice
07/06/199919  
09/27/200020+ +
08/26/2001,
09/11/2001
11  
08/25/2002,
09/24/2002
30+ +
10/11/200310  
Common Buckeye
Junonia coenia
07/06/19997  
08/06/20004  
09/11/20017  
09/30/20022  
Common Checkered-Skipper
Pyrgus communis
07/11/20001  
Common Sootywing
Pholisora catullus
08/26/20011  
06/07/20031  
Common Wood-Nymph
Cercyonis pegala
07/06/19998  
07/13/200013  
07/08/200125  
07/20/200212  
07/29/200320+ +
Coral Hairstreak
Satyrium titus
07/03/20005  
06/30/20017  
06/21/20023  
07/13/20037  
Dainty Sulphur
Nathalis iole
09/15/19991  
08/24/20011  
Delaware Skipper
Anatrytone delaware
07/07/20002  
07/11/20012  
07/20/20023  
07/09/20031  
Dion Skipper
Euphyes dion
07/05/200112  
07/16/200220  
07/09/20033  
Dun Skipper
Euphyes vestris
06/21/19991  
08/01/20003  
07/13/20013  
Eastern Comma
Polygonia comma
08/01/20004  
08/24/200115  
09/20/20012  
07/14/20022  
04/15/20037  
Eastern Tiger Swallowtail
Papilio glaucus
08/10/19991  
06/06/20001  
07/31/20014  
07/31/20023  
08/10/20033  
EasternTailed-Blue
Everes comyntas
08/10/199915  
08/11/200011  
08/25/200220  
07/29/20035  
European Skipper
Thymelicus lineola
06/21/199912  
07/03/20006  
06/21/200120+ +
06/21/200211  
06/24/200310  
Eyed Brown
Satyrodes eurydice
07/06/19993  
06/29/20004  
07/08/20011  
07/13/20035  
Fiery Skipper
Hylephila phyleus
08/16/199910  
09/10/20002  
08/26/20011  
09/07/20022  
Giant Swallowtail
Papilio cresphontes
08/20/19991  
07/25/20001  
08/26/20011  
08/25/20023  
08/14/20033  
Gray Comma
Polygonia progne
08/04/20012  
07/14/20022  
07/07/20031  
Great Spangled Fritillary
Speyeria cybele
06/21/19998  
06/22/20005  
07/05/200111  
07/03/20024  
07/14/200310  
Least Skipper
Ancyloxypha numitor
06/08/19992  
08/21/200020+ +
08/04/200120+ +
06/21/20025  
06/24/20033  
Little Glassywing
Pompeius verna
06/22/20011  
Little Wood-Satyr
Megisto cymela
06/06/20001  
06/12/20012  
06/24/200310  
Little Yellow
Eurema lisa
06/08/1999,
07/06/1999
1  
06/21/20021  
Meadow Fritillary
Boloria bellona
06/24/2001,
09/02/2001
5  
06/28/200215  
07/31/200320+ +
Monarch
Danaus plexippus
09/10/199910+ +
09/28/200010+ +
09/11/200110+ +
10/10/20023  
09/06/20035  
Mourning Cloak
Nymphalis antiopa
09/25/19992  
06/07/20001  
05/29/20012  
04/15/20025  
04/15/20033  
Northern Broken-Dash
Wallengrenia egeremet
07/14/20024  
Northern Pearly-Eye
Enodia anthedon
08/01/20004  
07/08/20011  
07/20/200215  
07/14/20034  
Orange Sulphur*
Colias eurytheme
07/06/199919  
09/27/200020+ +
08/26/2001,
09/11/2001
11  
08/25/2002,
09/24/2002
30+ +
10/11/200310  
Painted Lady
Vanessa cardui
06/06/19991  
08/06/20001  
08/26/200110  
10/06/20011  
09/17/200320+ +
Pearl Crescent
Phyciodes tharos
07/22/19996  
07/11/20008  
08/24/200119  
08/25/200220  
05/13/200320  
Peck’s Skipper
Polites peckius
09/30/19991  
06/07/20006  
06/12/20014  
06/07/20023  
06/20/20032  
Pipevine Swallowtail
Battus philenor
06/06/19991  
Purplish Copper
Lycaena helloides
09/07/19992  
09/01/20009  
09/11/20015  
08/27/20023  
09/09/200314  
Question Mark
Polygonia interrogationis
07/06/19994  
06/30/20004  
05/29/20019  
09/08/20022  
06/02/20031  
Red Admiral
Vanessa atalanta
09/10/19995+ +
06/06/20003  
05/17/200120+ +
06/21/20021  
07/29/20032  
Red-Spotted Purple
Limenitis arthemis
08/10/19992  
07/24/20001  
08/10/20014  
07/31/20025  
Sachem
Atalopedes campestris
09/10/20001  
Silver-Spotted Skipper
Epargyreus clarus
06/06/20004  
08/26/20017  
07/31/20025  
08/13/20035  
Spring Azure
Celastrina ladon
08/10/19993  
08/06/20005  
08/10/20013  
07/12/20022  
07/24/20032  
Tawny-Edged Skipper
Polites themistocles
06/06/19994  
06/07/20004  
05/29/20012  
06/07/200310  
Variegated Fritillary
Euptoieta claudia
08/26/20012  
Viceroy
Limenitis archippus
06/22/19996  
08/24/200010  
08/04/200118  
07/20/20025  
07/29/20033  
Wild Indigo Duskywing
Erynnis baptisiae
09/03/19991  
09/09/200010+ +
09/20/20015  
08/28/20023  
10/13/20033  
*Clouded Sulphur and Orange Sulphur are listed as separate species. Tom Peterson does not do separate counts for them since there are many intermediate-looking forms of them. He combines the data for both and the table above lists the same data for both species.