Sending a jolt of excitement through biologists who are trying to bring one of America's most endangered species back from the brink of extinction, a California condor has been spotted in San Mateo County, the first since 1904.

The bird, #597, also known as "Lupine," is a 3-year-old female that flew more than 100 miles north from Pinnacles National Park in San Benito County on May 30 and landed on a private, forested property near Pescadero, on the San Mateo County Coast.

It was photographed by an motion-activated wildlife camera. The property owner checked the camera several days later, made the discovery and reported the finding to biologists this week.

"It's very important," said Kelly Sorenson, executive director of the Ventana Wildlife Society, a nonprofit group in Salinas that works to restore condors to the wild.

"It shows that they really are spreading out in their range. It's very exciting. It shows that we're on the right track. The population is expanding. They are breeding on their own. They are finding food on their own."

Condors, whose wingspan can reach 9 feet, once ranged from British Columbia to Mexico. But because of habitat loss, hunting and lead poisoning, the majestic birds' population dwindled to just 22 nationwide by 1982.

In a desperate gamble to stave off extinction, federal biologists captured all remaining wild condors in 1987 and began breeding them in zoos. The birds' offspring have been gradually released back to the wild.

Today the California condor population has grown to 433. Of those, 238 live in the wild at Big Sur, Pinnacles, Southern California, Arizona, Utah and Mexico. The other 195 condors live in captivity, at places such as the Los Angeles Zoo. At a new wildlife hospital, the Oakland Zoo began treating wild condors last month.

The last condor verified in San Mateo County was observed in 1904, one mile west of the Stanford University campus, by professor Harold Heath.

Since condors have been reintroduced to the wild in recent decades, they have spread along the California coast, and Central California area, and more recently have turned up in the southern Sierra Nevada and the Tehachapi Mountains in Kern County.

Sorenson said that it's likely that condor #597 flew through Santa Cruz County. The birds also have been observed in rural Santa Clara County, east of Mount Hamilton, and in southern Alameda County. Because there are large numbers of sea lions, elephant seals and other marine mammals on the Santa Cruz-San Mateo coastline, Sorenson said that it's possible in future years, condors could begin to nest in the Santa Cruz Mountains and feed on marine mammals that wash up on the beach.

The main threat to condors continues to be poisoning from ingesting lead while eating dead animals shot by hunters. Last year, Gov. Jerry Brown signed a law banning lead bullets in hunting statewide by 2019.