Zoo officials said that this was the last batch of insects. The butterfly numbers dwindled mostly due to a decline in the numbers of their favorite flower, the early blue violet. Additionally, prolonged drought also negatively impacted the butterfly population.
The Oregon Zoo, which has been raising the insects in captivity since 1998, disclosed that they collect females from Mount Hebo in Tillamook County annually. Females are placed in a special lab where they are able to lay eggs. The young are kept in the lab over the winter and released into the wild as soon as they morph into pupae.
It is the first time that the zoo releases the butterflies on Mount Hebo. Karen Lewis, a zoo conservation expert who was part in the last action, said that the butterflies were released in the middle of the flight season. Lewis recalled that he saw the butterflies flying all around his team and across the meadows.
Conservationists are over-thrilled with Oregon Zoo’s last silverspot recovery effort. They said that the population is rebounding on the Oregon coast which was once their natural habitat. The silverspots were released in four locations along the coast in the past month.
Zoo officials said that they saw a young female visiting a nearby flower and a male joining it moments later. The event was a pleasant surprise for ecologists. Lewis explained that the Zoo has just put back the butterflies it took form Mount Hebo and a few extra.
The larvae are kept at the zoo over the winter, they are allowed to grow in spring and released in the summer into the meadows. Researchers picked Mt. Hebo because it is the home of the pupae’s parents.
Conservation researchers working with the zoo explained that the yellow-and-dark butterfly was once common on the coastal parts of northern California and all the way to British Columbia and Canada. It is currently considered a threatened species under the federal law, and there are only five species left in the wild.
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