(NEXSTAR) — Nearly two dozen species from 16 states that were listed as endangered have been delisted — but not because they’ve rebounded. Instead, the change in status is due to extinction.

Two years ago, the U.S. Fish and Wildlife Service proposed delisting 23 species. After a public comment period, they opted against delisting two: a perennial herb from Hawaii after new surveys found new habitats that could be suitable for the species, and the ivory-billed woodpecker, which FWS said it will continue to review.

The remaining 21, however, are now being delisted from the Endangered Species Act (ESA), FWS said in a Monday press release. The ESA was established in 1973 to protect plants and animals considered threatened or endangered in the U.S. So far, the ESA is credited with saving 99% of the species that received its protection, FWS said.

Many of the newly delisted species first received protection under the ESA in the 1970s and 1980s, and largely have not been seen since, according to FWS. The agency noted that while available data indicates the species are extinct today, they “were in very low numbers or likely already extinct at the time of listing.”

“Federal protection came too late to reverse these species’ decline, and it’s a wake-up call on the importance of conserving imperiled species before it’s too late,” said Service Director Martha Williams in the release.

Among those delisted species are eight birds found in Hawaii, one of which — the Kauai nukupuu — hasn’t been seen since 1899. Another, the Po`ouli, was last seen in 2004.

Also on the list are seven mussels found in Alabama. That includes the tubercled-blossom pearly mussel, which has also historically been found in Illinois, Indiana, Kentucky, Tennessee, Michigan, Ohio, and West Virginia. It was last spotted in 1969.

Below is the list of species from FWS that are now considered extinct, as well as where they were found, when they were first considered endangered, and the last confirmed sighting of the species.

More details on these species can be found here.

According to FWS, the final rule to delist these species will be published on Tuesday in the Federal Register and will become effective after 30 days.