Biologists released more than a dozen puaiohi at a wilderness preserve on Kauai to aid in the recovery of the endangered Hawaiian bird population.

In a joint effort, conservationists from the Kauai Forest Bird Recovery Project, state Division of Forestry and Wildlife, U.S. Fish and Wildlife Service-Pacific Islands Fish and Wildlife Office and the San Diego Zoo Global’s Hawaii Endangered Bird Conservation Program transported 15 puaiohi, also known as the small Kauai thrush, to the Alakai Wilderness Preserve on Kauai on Wednesday from breeding facilities on Maui and Hawaii island.

The release marks the end of the breeding program for the native songbird, which is found only on Kauai. Two decades ago biologists were worried about the plight of the puaiohi as there were fewer than 300 birds left on the Garden Isle.

Conservationists collected eggs from the wild population and brought them to breeding facilities on Maui and the Big Island where a captive breeding program was established.

The wild population has since increased to approximately 500 birds, prompting the closure of the breeding program. Biologists will direct their attention to habitat management and predator control for the wild puaiohi population, according to Lisa “Cali” Crampton, project coordinator of the Kauai Forest Bird Recovery Project.

“It was a bittersweet moment today to release these birds back out into the wild,” said Bryce Masuda, conservation program manager of the San Diego Zoo Global’s Hawaii Endangered Bird Conservation Program, in an interview with DLNR on Wednesday. “We’ve been caring for puaiohi for many years, breeding the species, and today marks the end of that program. So we’re happy for the species, to be able to shift the focus now to working on these species out in the wild.”

Conservationists also plan to work on increasing breeding populations for two other critically endangered bird species endemic to Kauai: the akikiki, or Kauai creeper, and akekee, or Kauai akepa.