Giant Swallowtail Butterfly Alert!!!

Last week the Giant Swallowtail butterfly visited our garden for a brief moment. I ran indoors to get my camera but it had departed by the time I returned. This morning my my friend John, who lives across from Folly Cove, emailed to say he too has spotted a Giant Swallowtail. John and I correspond regularly about butterfly sightings–I love to hear about what he is seeing on the other side of the island– and this is the first time both he and I have observed Giant Swallowtails in our gardens.

Giant Swallowtail Butterfly (Papilio cresphontes)

Photo Courtesy Marti Warren

One of my readers, Marti Warren, wrote in on Monday that she spotted a Giant Swallowtail Butterfly last week in her garden in Amherst, New Hampshire. 

From my favorite butterfly book, Butterflies of the East Coast by Cech and Tudor, “Although they are not regular migrants, Giant Swallowtails have appeared with some consistency as vagrants in the North, and occasionally form colonies.”

On the range map provided in the above book, the northern border of Massachusetts is at the end of the Giant Swallowtails range so I think it is fairly unusual to see one in central New Hampshire.

Male Black Swallowtail Butterfly (Papilo polyxenes)

Three easy ways to know whether you are seeing the more common male Black Swallowtail or the Giant Swallowtail.

1) The wingspan of the male Black Swallowtail is approximately 3.2 inches; the Giant Swallowtail’s wingspan nearly five inches.

2) Both the male and female Giant Swallowtails have a band of yellow spots that converge near the apex.

3) Additionally the only blue irredescence on the Giant Swallowtail is a semi-circular “eyebrow” over the orange and black eyespots.

Let us know if you think you have seen a Giant Swallowtail in your garden recently. If you have a photo, even better!