The tiger swallowtail, Pterourus glaucus, is a big, beautiful butterfly that is common in the Eastern United States. There are closely related species throughout North America. It is related to the black swallowtail listed earlier in this guide and has many of the same features and habits. The caterpillar feeds on wild cherry, ash, and a number of other trees. Like other swallowtail butterflies, the female butterfly lays eggs on plants in the late spring and early summer. The caterpillar takes a few weeks to grow and pupate. Swallowtail butterfly caterpillars often resemble bird droppings when they are immature, and this species is no exception. Full-grown tiger swallowtail caterpillars have small false eyes near the front of the body. These are purely for protection and are not actually eyes (a related species, the spicebush swallowtail, has truly beautiful and large fake eyes). Like all swallowtail caterpillars, this species possesses "osmeteria"—a foul-smelling, forked organ near the head—that it can pop out to deter predators.