PORTLAND, Ore. — When you think of the Oregon Zoo, animals like lions, tigers and elephants probably come to mind. But the zoo also works closely with the some of the smallest creatures, like caterpillars — which later become butterflies.
The Oregon silverspot butterfly has slowly been dying off for decades. It has been considered a threatened species under the Endangered Species Act since 1980.
In recent years, the zoo launched a program to help bring up the species' population in its native habitat.
Amber Valdez, who works at the Oregon Zoo's butterfly conservation lab, is one of the staffers trying to save the silverspot butterfly. She spends hours with young silverspot caterpillars to help ensure their survival.
“They lay up 200 to 400 eggs per female butterfly in the wild. All of those would not survive," said Valdez. "When we bring them to the lab, we can make sure they have the best conditions to survive."
In 2019, the Oregon Zoo became the first facility to successfully breed silverspots. The zoo works closely with Coffee Creek Correctional Facility in Wilsonville, which provides plants to feed the caterpillars. The zoo also gets help from the Oregon Department of Forestry, which works to restore the butterflies' natural habitat.
Among the sites where conservationists are working to reintroduce the species is Saddle Mountain in the Oregon Coast Range, where the silverspot hasn't been seen since 1972.
Valdez said it can be really tough for the silverspot butterfly to thrive in the wild, especially with our changing climate.
“If it gets warmer and then all of the sudden we get snow like we saw [in April], and then we warm up, the warmer temperatures trigger them to wake up, but if it snows it could kill them,” said Valdez.
She said the caterpillars have a 70% to 90% chance of survival inside the lab at the Oregon Zoo; out in the wild, their chance of survival is closer to 5%.
The zoo currently has more than 2,000 caterpillars that will eventually turn into butterflies that will be sent into the wild to help the species thrive in the wild again.