If you've spotted a Taylor's checkerspot butterfly in the wild in the Pacific Northwest, you are lucky. The butterflies, which are listed under the U.S. Endangered Species Act, are very nearly extinct. 

But, later this month, the Oregon Zoo plans to release of record number of Taylor's checkerspot caterpillars into native northwest habitats.

The 5,398 larvae, according to a release from the zoo Friday, were recently roused from winter dormancy and are now "very hungry caterpillars."

This will be the largest number of butterflies introduced into the wild since the zoo began its conservation effort 15 years ago.

"The Taylor's checkerspot is one of the Northwest's most beautiful—and most endangered—butterflies," Mary Linders, a species recovery biologist with Washington Department of Fish and Wildlife, a zoo partner, says in a statement. "Without large, connected populations, the butterflies struggle to survive."

A few of the zoo-reared checkerspot caterpillars will stay behind, laying eggs to be released again next year.

Habitat degradation due to invasive species, urban development and agriculture have degraded 99 percent of the Taylor's checkerspots native habitat.

Since 2004, Linders says the zoo has released 28,000 of the butterflies in the northwest.

"We've started seeing Taylor's checkerspots at locations where they haven't been documented in years," Linders says. "It gives us hope for a species that is very close to disappearing completely."