A Canadian Tiger Swallowtail. I Think.

Canadian Tiger Swallowtail (Papilio canadensis)

The Eastern and Canadian Tiger Swallowtails are nearly identical except for bars and markings on the ventral side of the wings. You usually never see the bottom of the wing unless the butterfly is puddling: taking nutrients from wet soil. And that is what this one was doing.

Canadian Tiger Swallowtails puddling.

Puddling is usually done by male tiger swallowtails, but I have seen reference to females doing it occasionally. Apparently the males "gain virility" with the nutrients and salts obtained in the soil. Very often, there are beautiful groups of butterflies puddling. Yesterday there was just this one. I have only seen two this year because the two hard killer frosts in late May killed the lilac blossoms. When the lilacs bloom they are covered in the tiger swallowtails.

I do not have a verified photo of an Eastern Tiger. Usually they are labeled "tiger swallowtails and allies." But yesterday's tiger showed me under its wings. You will see a nearly solid black straight band on the edge of the wing. Eastern tigers have broken bands. My tentative identification is not yet confirmed, but I am feeling confident.

Ventral side of wing

The Canadian tigers are smaller than the Eastern tigers. They also appear before the Easterns. The species will also hybridize, creating new variations in their patterns. Identification can get complicated, if not impossible at times. 

More information:

• Canadian Tiger Swallowtails Puddling (Mary Holland)

• Taming the Tigers: An Identification Guide to Canadian and Eastern Tiger Swallowtails and their Intergrades (Bryan Pfeiffer)

• Observations on the Puddling Behavior of the Canadian Tiger Swallowtail Butterfly, Papilio Glaucus Canadensis in Northern Michigan (J. Mark Scriber)

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