Giant Swallowtail

Papilio cresphontes

The Giant Swallowtail is an uncommon stray in most parts of Wisconsin. I saw my first Giant Swallowtail near Spring Green in 1988. It was a road kill I spotted while driving about 55 mph. It was unmistakable even at that speed, and much to my passengers chagrin, I stopped the car abruptly to retrieve this specimen. I later saw several in the parking lot at House-on-the-Rock and was in awe watching them fly among the trees. Later that year this species made it to Waushara County, where I tried in vain to locate larva on the hostplant, Prickly Ash. I had seen only one butterfly of this species in Waushara County since that year, until 2007 and the last two years I have seen a three of these in Waushara County. The top photo was taken in Buffalo County by Mike O’Connor. The photo clearly shows the Giant Swallowtails larger size in comparison to the Eastern Tiger Swallowtail. The sixth photo is of the distinctive caterpillar of the Giant Swallowtail that looks very much like a bird dropping. The photo was taken by Curt Lehman in Maryland. 2008 was a very good year for Giant Swallowtails with this species being reported from farther north than it had ever been reported in Wisconsin and from nearly half the counties.

Weekly sightings for Giant Swallowtail

Identifying characteristics

Above: The largest Wisconsin butterfly with a wingspan that sometimes exceeds 5 inches. The upper wings are brownish with two bold yellow lines of spots that cross near the apex of the front wing, forming an “x”. Below: yellow with black veins and borders. The tail is spoon like with a yellow spot that can be seen from above or below.

Similar species

This species is like no other in Wisconsin

Habitat

Woodlands and open areas near woodlands, where the larval hostplant, Prickly Ash is found.

Flight

Two broods; early May and then in late July and August. This species strays northward occasionally. Ferge (2002) lists this species as widespread, but it is not clear that colonies of this species, especially farther north, are able to survive severe winters, and populations, rather than permanent residents, may periodically become repopulated from the south.