It’s a small but sure sign that the California condor population is rebounding after near-extinction, as six California condors were recently tracked in Contra Costa County, the first flock of these birds to fly through the county in 100 years.

California condors are North America’s largest land bird, with a nearly 10-foot wingspan, and they can live up to 60 years old. But they’re better known for having nearly gone extinct, with only about two dozen of them still alive as of 1979. But these big, majestic birds have been slowly bred in captivity and reintroduced into the wild, and there are now around 500 of them, and they’re turning up in places where they haven’t been seen in a century.

Add Contra Costa County to that list. NBC Bay Area reports that a California condor flock has been tracked visiting Contra County for the first time in 100 years. Per GPS tracking data, six California condors (all tagged) flew through Round Valley and Morgan Territory Regional Preserves, not far from Mount Diablo. They reportedly stayed only a few hours, then flew to a location in Stanislaus County, some 80 miles away,

“This is amazing news,” Save Mount Diablo land conservation director Seth Adams said in a release. “This is the first flock of California condors to visit Contra Costa in 100 years, and the first record of one flying west of Diablo’s peaks. I started chasing condors 40 years ago and since the recovery program began, I’ve been hoping the birds would reclaim Mount Diablo. Now they are.”

It’s critical to note Adams said it was the “first flock” tracked in Contra Costa County, as two individual California condors have passed through in recent years. According to Save Mount Diablo, one individual bird became the first California condor observed in Contra Costa county in a century when tracked at the Round Valley–Morgan Territory area in 2021. Last year, another was tracked passing over the Brushy Peak Regional Preserve.

Wildlife officials stress that the condors’ return is contingent on humans adopting a “leave no trace” philosophy in parks with mountains. In 2021, one of the very condors that just passed by Mount Diablo (a male known as Condor 943) got a beer can stuck on his lower beak, and he needed to be captured to have it removed. Three of these condors have been treated for lead poisoning, which is why lead ammunition is no longer legal in the state, as that lead may have been in their prey.

These more frequent trackings of California condors are an encouraging sign that their population may, someday, be back to healthy levels. Though there is a potential flip side to this, because as they proliferate, a group of them might take over your back deck.

Related: For the First Time In Over a Century, California Condors Return to NorCal Redwoods [SFist]

Image: NPS Photo by Gavin Emmons