On August 7, 1985, USFWS biologists captured 5-year-old male California condor AC-4 at Bitter Creek National Wildlife Refuge in Kern County, California.
AC-4 turned out to be integral to the recovery of the California condor population. While part of the captive breeding program, he successfully sired 30 chicks that were released into the wild population -- the third most productive sire in the program. He was also part of the pair that produced the first egg and first chick from wild birds in captivity in 1988.
Fast forward to December 29, 2015, 35-year-old AC-4, re-branded as California condor number 20, was released in the same area where he was captured. At that time, he was one of four remaining condors of the original 22 birds brought into captivity in the 1980s. Condors can live to 60.