City officials identify the first-flighter as Ilahay. It was not a solo flight. Her mom Clara went with her.
The young falcon soared over the Martin Luther King Jr. Library around 3:20 p.m.
Ilahay slipped a bit back down the building, but was able to recover and get back into her nest area.
Falcon fans, along with members of the Santa Cruz Predatory Bird Research Group, have watched the birds from dawn until dusk daily since Friday waiting for Clara and Esteban Colbert's babies to leap from their nest.
City officials said volunteers will continue to monitor the birds' movements over the next few days and weeks.
They acknowledge the birds will face dangers, especially if they land on the street.
Clara and her kin have been celebrities in San Jose since city employees noticed her and a former mate, Jose, in 2006. This is her biggest family so far. She hatched three female chicks with Jose in 2007 and three more with another mate, Carlos, in 2008.
Thousands have been watching the FalconCam on the city's Web site and the Santa Cruz Predatory Bird Research Group's Web site.