Oregon Silverspot

Once found in coastal headlands from northern California to southern Washington, the Oregon silverspot butterfly (Speyeria zerene hippolyta) has disappeared from all but a handful of sites along the Oregon coast. The Oregon silverspot population at Cascade Head declined from 1,392 butterflies in 1989 to 57 in 1998. Development, pesticides, fire management, introduced plant species, grazing and off-road vehicles are all reasons for this butterfly’s decline.

Oregon Silverspot Fast Facts

• Federally listed as threatened.
• Lab-rearing project at the zoo started in 1999.
• Eggs are laid one at a time and the caterpillars live solitary lives.
• The caterpillars only eat Viola adunca leaves, and each caterpillar eats about 250 leaves to become a butterfly.
• Average wingspan for adult butterflies is a little over an inch.

You can find more information about the Oregon Silverspot captive rearing program at the Oregon Zoo in the overview booklet.