(KRON) — Researchers in Contra Costa County said they are tracking a flock of California condors in the Mount Diablo region. It’s the first time the critically endangered birds have been spotted in the county in 100 years, according to the Save Mount Diablo organization.

The California condor nearly went extinct in the 1980s, largely due to lead poisoning from hunting ammo left in dead animals. The species population was down to only 22 individuals.

After tireless recovery efforts over the past 30 years, California condors were brought back from the brink of extinction and starting in the 1990s, some were released back into the wild. Today, there are more than 500 condors living in the wild and in captivity.