Resident peregrine falcons Clara and father Fernando El Cohete welcomed their first chick on Easter Sunday, and two more eggs hatched early Monday morning, said Glenn Stewart, director of the Santa Cruz Predatory Bird Research Group at UC Santa Cruz.
The fourth egg is expected to hatch in the next two days, Stewart said.
The falcon family is nested on the building's south wall about 20 stories off the ground.
This is Clara's seventh nesting season at City Hall and her first with new mate Fernando El Cohete, which translates to "the rocket" in Spanish.
"The babies achieve most of their body growth by the time they're 3 weeks old but don't have feathers yet," Stewart said.
Stewart said he will visit the family's nest in several weeks, around April 22 or 23, and will place a tag on the chicks' legs, allowing researchers to track them.
The process only takes about 20 minutes but the parents usually get upset, Stewart said.
While tagging the chicks, Stewart will also determine their gender.
The chicks usually depart the nest a month after they learn to fly, Stewart said.
Anyone in the San Jose area can go to City Hall and view the falcons. A popular viewing spot is the top level of the city's Fourth Street garage, located across the street from City Hall, Stewart said.
A live stream and videos of the falcons is available on the Santa Cruz Predatory Bird Research Group's website at www.scpbrg.org.