Spring First Sightings Dates
| Butterfly Species | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 |
| Mourning Cloak ( Nymphalis antiopa ) | 3/30 | 3/29 | 2/29 | 3/21 | 3/12 | 3/17 |
| Eastern Comma ( Polygonia comma ) | 3/26 | 3/27 | 3/4 | 3/21 | 3/12 | 3/16 |
| Milbert's Tortoise Shell ( Nymphalis milberti ) | 4/11 | 3/20 | 3/5 | 3/21 | 3/13 | 6/15 |
| Cabbage White ( Pieris rapae ) | 3/30 | 3/31 | 3/23 | 4/1 | 4/15 | 3/27 |
| Spring Azure ( Celastrina ladon ) | 4/11 | 4/8 | 4/1 | 4/14 | 4/14 | 4/18 |
| Red Admiral ( Vanessa atalanta ) | 4/5 | 4/24 | 4/16 | 4/8 | 4/16 | 4/16 |
| Compton's Tortoise Shell ( Nymphalis vau-album ) | 4/12 | 3/31 | 4/14 | 4/8 | 3/12 | 4/12 |
| American Painted Lady ( Vanessa virgiensis ) | 5/3 | 4/25 | 4/22 | 4/8 | 4/16 | 4/24 |
| Brown Elfin ( Incisalia augustinus ) | 4/25 | 4/14 | 4/14 | 4/22 | 4/16 | 4/14 |
| Mustard White ( Pieris ) | 4/11 | 4/26 | 4/14 | 4/29 | 4/24 | 4/18 |
| Tiger Swallowtail ( Papilio glaucus ) | 5/5 | 4/26 | 4/15 | 4/23 | 5/4 | 4/27 |
| Sleepy Duskywing ( Erynnis brizo ) | 4/25 | 4/26 | 4/18 | 4/28 | 4/19 | 4/26 |
| Juvenal's Duskywing ( Erynnis juvenalis ) | 5/5 | 5/2 | 4/23 | 4/28 | 4/29 | 5/3 |
| Black Swallowtail ( Papilio polyxenes ) | 5/12 | 4/25 | 4/24 | 5/2 | 4/20 | 5/3 |
| Clouded Sulphur ( Colias ) | 5/4 | 4/25 | 4/16 | 4/30 | 4/24 | 5/3 |
| Orange Sulphur ( Colias ) | 6/28 | 5/2 | 4/23 | 5/1 | 5/9 | 5/4 |
| Question Mark ( Polygonia interrogatorius ) | 5/16 | 4/28 | 4/22 | 4/29 | 5/4 | 4/14? |
| Pine Elfin ( Incisalia niphon ) | 5/5 | 4/26 | 4/28 | 4/29 | 5/5 | 5/17 |