A 35-year-old male California condor that has served a pivotal role in returning condors to the skies above California for the past 30 years was returned to the wild on December 29, 2015 by biologists at Bitter Creek National Wildlife Refuge in Kern County, California.

The condor, known as AC-4, was captured on August 7, 1985, by a team of U.S. Fish and Wildlife Service (Service) biologists at Bitter Creek National Wildlife Refuge as part of an effort to prevent extinction of the species. He was one of 22 California condors - the last remaining on Earth - captured between 1983 and 1987 to breed in captivity as part of the Service-led California Condor Recovery Program.

On December 29, re-branded as California condor number 20, he was released in the same area where he was captured.

“Watching this California condor, who has been so instrumental to recovery of his species, rejoin the wild flock, is an emotional and historic moment,” said Joseph Brandt, lead condor biologist with Service. “It’s like seeing him come full circle.”

Jesse Grantham, former California Condor Recovery Coordinator, was part of the team to capture AC-4 in 1985, and had monitored the bird extensively. “Many people have poured their heart and soul into the recovery of these remarkable birds, and it is an amazing feeling to be here with many of those individuals who have dedicated their lives to condor recovery. The bird can now live out the remainder of its life back in the wild, while his legacy and contributions to condor recovery live on in future generations.”

Children and young adults from the Pasadena Young Birders Club joined Brandt, Grantham and many others who have worked on condor conservation for decades, to be a part of the once-in-a-lifetime experience.

Fifteen-year-old birder Diego Blanco and his family watched in awe as the condor took flight. "[He] soared to our left, away from the pen and over the canyon. He crossed a ravine, passed over several ridges, and continued his leftward flight, following the canyon as he went."

Reflecting on his experience, Diego continued, "AC-4 represents a thin, but unbroken link to the 10,000 years of condors in North America, and witnessing his release was a truly inspirational moment..." [Read Diego's full account of his experience here: <a href="http://www.fws.gov/FieldNotes/regmap.cfm?arskey=36843" rel="nofollow">www.fws.gov/FieldNotes/regmap.cfm?arskey=36843</a>].

AC-4 has been integral to the recovery of the California condor population. He has successfully sired 30 chicks that have been released into the wild population -- the third most productive sire in the program. Along with female mate UN-1 (California condor number 13), the pair produced the first egg and first chick from wild birds in captivity in 1988.

Recent genetic work indicates his parents were original genetic founders of the captive population, and those genes are now well represented across the captive population.

AC-4 remained part of the captive breeding program at San Diego Zoo from 1985 to 2014, when he was transferred to Pinnacles National Park to mentor juvenile California condors who were preparing to be released into the wild. He was transferred to a flight pen at Bitter Creek National Wildlife Refuge in September to prepare for his release into the wild.

AC-4 is one of four remaining condors of the original 22 birds brought into captivity in the 1980s.

With a wingspan of 9.5 feet and weighing up to 25 pounds, the California condor (Gymnogyps californianus) is the largest land bird in North America. These majestic creatures historically ranged from California to Florida and Western Canada to Northern Mexico. By the mid-20th century, condor populations had dropped dramatically, and by 1967 the California condor was listed as "endangered" by the federal government. In 1982, only 23 condors existed world-wide. By 1987, all remaining wild condors were placed into a captive breeding program. Thus began an intensive recovery program to save the California condor from extinction.

Since 1992, when the Service began reintroducing captive-bred condors to the wild, the population has grown to about 420 birds.