Pale Swallowtail

Walking through some nearby hills, we came upon this gigantic butterfly. After coming home I got help from Wikipedia and learned that this is a Pale Swallowtail.  I have regular Swallowtail butterflies in my yard, but not as big as this. 

A stream meanders through the canyon off to the right. Makes sense that these butterflies would be nearby —

Though not as common as the Western Tiger Swallowtail, the Pale Swallowtail can be seen in large numbers at puddling parties where up to a dozen or more males may be seen gathered. There they join other species to sip water from damp soil to obtain nutrients for mating …  Tiger stripes and borders are thicker than those of Western Tiger Swallowtails. The wingspan is typically 3.5 to 4.5 inches. [Wikipedia]