Peak Count Data for Butterflies at Fermilab
Sorted by Scientific 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 Common Name - by Number Found in 1999 - 2000 - 2001 - 2002 - 2003

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

Anatrytone delaware
Delaware Skipper
07/07/20002  
07/11/20012  
07/20/20023  
07/09/20031  
Ancyloxypha numitor
Least Skipper
06/08/19992  
08/21/200020+ +
08/04/200120+ +
06/21/20025  
06/24/20033  
Atalopedes campestris
Sachem
09/10/20001  
Battus philenor
Pipevine Swallowtail
06/06/19991  
Boloria bellona
Meadow Fritillary
06/24/2001,
09/02/2001
5  
06/28/200215  
07/31/200320+ +
Celastrina ladon
Spring Azure
08/10/19993  
08/06/20005  
08/10/20013  
07/12/20022  
07/24/20032  
Cercyonis pegala
Common Wood-Nymph
07/06/19998  
07/13/200013  
07/08/200125  
07/20/200212  
07/29/200320+ +
Colias eurytheme*
Orange Sulphur
07/06/199919  
09/27/200020+ +
08/26/2001,
09/11/2001
11  
08/25/2002,
09/24/2002
30+ +
10/11/200310  
Colias philodice*
Clouded Sulphur
07/06/199919  
09/27/200020+ +
08/26/2001,
09/11/2001
11  
08/25/2002,
09/24/2002
30+ +
10/11/200310  
Danaus plexippus
Monarch
09/10/199910+ +
09/28/200010+ +
09/11/200110+ +
10/10/20023  
09/06/20035  
Enodia anthedon
Northern Pearly-Eye
08/01/20004  
07/08/20011  
07/20/200215  
07/14/20034  
Epargyreus clarus
Silver-Spotted Skipper
06/06/20004  
08/26/20017  
07/31/20025  
08/13/20035  
Erynnis baptisiae
Wild Indigo Duskywing
09/03/19991  
09/09/200010+ +
09/20/20015  
08/28/20023  
10/13/20033  
Euphyes conspicua
Black Dash
07/06/19992  
07/07/20002  
07/13/20012  
07/12/20022  
07/16/20031  
Euphyes dion
Dion Skipper
07/05/200112  
07/16/200220  
07/09/20033  
Euphyes vestris
Dun Skipper
06/21/19991  
08/01/20003  
07/13/20013  
Euptoieta claudia
Variegated Fritillary
08/26/20012  
Eurema lisa
Little Yellow
06/08/1999,
07/06/1999
1  
06/21/20021  
Everes comyntas
EasternTailed-Blue
08/10/199915  
08/11/200011  
08/25/200220  
07/29/20035  
Hylephila phyleus
Fiery Skipper
08/16/199910  
09/10/20002  
08/26/20011  
09/07/20022  
Junonia coenia
Common Buckeye
07/06/19997  
08/06/20004  
09/11/20017  
09/30/20022  
Libytheana carinenta
American Snout
07/21/20001  
09/29/20011  
Limenitis archippus
Viceroy
06/22/19996  
08/24/200010  
08/04/200118  
07/20/20025  
07/29/20033  
Limenitis arthemis
Red-Spotted Purple
08/10/19992  
07/24/20001  
08/10/20014  
07/31/20025  
Lycaena helloides
Purplish Copper
09/07/19992  
09/01/20009  
09/11/20015  
08/27/20023  
09/09/200314  
Lycaena hyllus
Bronze Copper
06/08/1999,
08/16/1999
3  
08/07/20003  
08/03/20015  
09/11/20021  
07/29/20033  
Megisto cymela
Little Wood-Satyr
06/06/20001  
06/12/20012  
06/24/200310  
Nathalis iole
Dainty Sulphur
09/15/19991  
08/24/20011  
Nymphalis antiopa
Mourning Cloak
09/25/19992  
06/07/20001  
05/29/20012  
04/15/20025  
04/15/20033  
Papilio cresphontes
Giant Swallowtail
08/20/19991  
07/25/20001  
08/26/20011  
08/25/20023  
08/14/20033  
Papilio glaucus
Eastern Tiger Swallowtail
08/10/19991  
06/06/20001  
07/31/20014  
07/31/20023  
08/10/20033  
Papilio polyxenes
Black Swallowtail
08/17/19992  
08/30/20002  
08/04/200112  
07/20/20022  
06/25/20033  
Pholisora catullus
Common Sootywing
08/26/20011  
06/07/20031  
Phyciodes tharos
Pearl Crescent
07/22/19996  
07/11/20008  
08/24/200119  
08/25/200220  
05/13/200320  
Pieris rapae
Cabbage White
06/21/199930  
08/11/200020+ +
08/04/200130+ +
08/25/200220+ +
09/06/200312  
Polites peckius
Peck’s Skipper
09/30/19991  
06/07/20006  
06/12/20014  
06/07/20023  
06/20/20032  
Polites themistocles
Tawny-Edged Skipper
06/06/19994  
06/07/20004  
05/29/20012  
06/07/200310  
Polygonia comma
Eastern Comma
08/01/20004  
08/24/200115  
09/20/20012  
07/14/20022  
04/15/20037  
Polygonia interrogationis
Question Mark
07/06/19994  
06/30/20004  
05/29/20019  
09/08/20022  
06/02/20031  
Polygonia progne
Gray Comma
08/04/20012  
07/14/20022  
07/07/20031  
Pompeius verna
Little Glassywing
06/22/20011  
Pontia protodice
Checkered White
09/05/20011  
Pyrgus communis
Common Checkered-Skipper
07/11/20001  
Satyrium acadica
Acadian Hairstreak
06/23/19991  
07/08/20011  
07/03/20021  
07/09/20031  
Satyrium calanus
Banded Hairstreak
06/21/19995  
06/22/20002  
06/25/20015  
07/14/20021  
07/14/20034  
Satyrium titus
Coral Hairstreak
07/03/20005  
06/30/20017  
06/21/20023  
07/13/20037  
Satyrodes eurydice
Eyed Brown
07/06/19993  
06/29/20004  
07/08/20011  
07/13/20035  
Speyeria cybele
Great Spangled Fritillary
06/21/19998  
06/22/20005  
07/05/200111  
07/03/20024  
07/14/200310  
Thymelicus lineola
European Skipper
06/21/199912  
07/03/20006  
06/21/200120+ +
06/21/200211  
06/24/200310  
Vanessa atalanta
Red Admiral
09/10/19995+ +
06/06/20003  
05/17/200120+ +
06/21/20021  
07/29/20032  
Vanessa cardui
Painted Lady
06/06/19991  
08/06/20001  
08/26/200110  
10/06/20011  
09/17/200320+ +
Vanessa virginiensis
American Lady
06/07/20001  
05/17/20015  
05/03/20022  
04/25/20031  
Wallengrenia egeremet
Northern Broken-Dash
07/14/20024  
*Colias philodice (Clouded Sulphur) and Colias eurytheme (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.