'Very active' yellow butterfly boom in Washington state

Yellow butterflies almost half the size of a human hand have transformed parts of the Evergreen state into a big garden party.

They are called tiger swallowtails. And while they're commonly seen in our region this time of year, more of them are flitting about than usual this summer, said entomologist Richard Zack of Washington State University.

"Tiger swallowtails are perhaps our most recognized and beautiful butterflies and they are very evident this summer," he explained.

Though not as famous as the orange and black monarch, the tiger swallowtail butterfly displays striking black markings ac...