Excerpts from Jim Conrad's
from the June 21, 2009 Newsletter, issued from the Siskiyou Mountains west of Grants Pass, Oregon:
A PALE TIGER SWALLOWTAIL
Blackberries are at their lovely peak of flowering here and butterflies just love them. This week I spotted what any butterfly fancier from the East might call a Zebra Swallowtail, but it was a bit different, so I figured I had its Western counterpart. That's it above.
That's the Pale Tiger Swallowtail, PTEROURUS EURYMEDON. Tiger swallowtails -- genus Pterourus -- are generally yellow and black, so this black-and- white one is a bit anomalous. Zebra swallowtails are the ones supposed to be black and white.
Though my field guide says that this species is less numerous than other tigers, I understand why it's the main swallowtail around here: Its caterpillars' preferred food is the buckthorn bush, genus Ceanothus, which I've described several times as being absolutely abundant here.
Pale Tiger Swallowtails are distributed in mountainous and hilly country from British Columbia and Montana south to Mexico's Baja California.