A long-running effort to bring the Houston toad back to Bastrop State Park has taken a big step, with more than one million endangered toad eggs released as part of a renewed recovery push.

The Texas Parks and Wildlife Department is leading the work with the Houston Zoo, Amphibian and Reptile Conservancy, and the U.S. Fish and Wildlife Service.

Officials said the release is part of an effort to restore the species to the park after the Houston toad population disappeared following the 2011 Bastrop County Complex Wildfire. They said it has been about a decade since the park last had a resident population of Houston toads.

Conservation leaders said years of habitat restoration work made the reintroduction possible.

There were earlier attempts to restore the population in 2015 and 2019, but both were unsuccessful. Experts said this year may offer their best chance.

“We got close in 2019,” said TPWD herpetologist Paul Crump, according to WFAA. “But this is the most eggs released in a single year to date in the state park.”

The eggs will be released at three sites, two in Bastrop County and one in Milam County.

“Each of these sites is managed a little bit differently,” said TPWD herpetologist Paul Crump. “Going forward, we can measure the varying success of these populations to determine what environmental factors are helping them along. Then we can try to replicate the most important of these factors in our other sites and across the state.”

Restoration crews said habitat improvements in Bastrop State Park have brought conditions back to a state suitable for the endangered amphibian.

The Houston toad was one of the first amphibians listed as federally endangered in 1970 because of habitat fragmentation and urban development. Officials said drought, feral hogs and invasive fire ants have further reduced populations.

Conservation officials said protecting and restoring habitat is critical to preventing extinction.

Read more from WFAA.