Oregon Zoo has been working towards restoring the population of silverspot butterflies in the wild and in a step in the direction, its officials have released hundreds of butterflies.
The work is being carried out by the Zoo in collaboration with conservation partners and under the program, officials have been making weekly trips to the coast and releasing hundreds of butterfly pupae to the grassy headlands and salt-spray meadows, which are said to be the last remaining habitat for the silverspot.
Silverspot butterflies are a threatened species and once found in abundance in coastal grasslands from northern California up into British Columbia, they are now found in a few locations only because of extensive habitat loss and disappearance of its host plant, the early blue violet.
As part of the conservation efforts, zoo officials have released nearly 450 zoo-reared silverspots at four field sites along the Oregon Coast. Officials tuck “pupae pockets” into mesh pens designed to keep out hungry predators like voles and white-crowned sparrows. These pupae then emerge as fully formed butterflies, launching themselves into the meadow to complete the release process in a matter of weeks.
Silverspots need to get on with their lives quickly. With a life expectancy of about two weeks, the females have just enough time to mate, locate a patch of violets in which to lay their eggs, and complete their lives. During last week’s release, one of the newly emerged females fluttered straight to a nearby daisy and was joined there moments later by a male silverspot.
The Oregon zoo has been actively working towards silverspot recovery efforts since 1998; however, this is the first time that the zoo officials have released the butterflies at the U.S. Forest Service site atop Mount Hebo in Tillamook County.
Mount Hebo has long been one of the source sites for the recovery effort: Each year, female silverspots are collected from the area and brought to the zoo’s butterfly conservation lab to lay eggs. The eggs hatch into tiny larvae (caterpillars), which are kept safe over the winter so they can grow in the spring and be released next summer along their coastal habitat, beginning the cycle anew.