As the winter breeding season approaches, the peregrine falcons that call UC Berkeley home may expand their population.

Students at UC Berkeley may be able to witness the loud screeching and midair dives characteristic of the falcons’ mating process, after peregrine falcons claimed the Campanile as a nesting ground in April. Noah Whiteman, a UC Berkeley associate professor of integrative biology and a bird expert, said this is “exciting,” considering the birds were almost extinct 50 years ago because the chemical pesticide DDT depleted peregrine eggs of calcium.

DDT use was banned in 1972 by the U.S. Environmental Protection Agency. In 1975, a falcon conservation effort began in Santa Cruz, spearheaded by the nonprofit Peregrine Fund and the Santa Cruz Predatory Bird Research Group, or SCPBRG. According to Whiteman, the effort was so successful that peregrine levels in California have returned to pre-DDT levels.

“It really is the product of a success story of human intervention. … It was not the government getting involved. It was concerned individuals and scientists,” Whiteman said. “It’s beautiful. It is there for our descendants to enjoy. The birds can be themselves.”

In June, SCPBRG director Glenn Stewart, along with Doug Bell, wildlife program manager of the East Bay Regional Park District, put bands on the two peregrine chicks living atop the Campanile to track and identify them. Stewart said he plans to continue banding the chicks seasonally as long as he is permitted to do so.

Stewart added that because there is sufficient light and abundant food, peregrines can live in the Bay Area year-round, unlike their arctic counterparts that migrate more than 10,000 miles annually from the Arctic to Chile because of cold, dark winters. Peregrines now reside on many tall buildings, cranes and bridges in the Bay Area, which simulate the natural high cliffs they use as a vantage point to scope out their prey, according to Stewart.

Whiteman said peregrines usually lay eggs after the new year, and any chicks of the pair living atop the Campanile will likely fledge, or leave the nest, sometime in the spring. Peregrines are highly territorial, and if the group on the campanile dies, another pair will occupy the space, according to Whiteman.

There are about 22 peregrine nests in the Bay Area, and the pair living on the Campanile is the first known couple to nest in Berkeley, according to Allen Fish, director of the Golden Gate Raptor Observatory. Fish added that peregrines have adapted well to urban environments.

“It’s pretty cool to have them there, right in the middle of campus. They are an icon of wilderness,” Stewart said. “People should enjoy them. They should sit down on the lawn and take pictures of them. … It’s a testimony to (how) conservation works if people dedicate themselves.”

One of Whiteman’s goals is for members of the UC Berkeley community to be aware and appreciative of the wildlife that exists on campus. He added that because peregrines are predatory birds and will kill songbirds and pigeons, it is a reminder to humans that they are a part of the natural world.

“The birds that are here … they represent the best of the human spirit,” Whiteman said. “I love that they are in the Campanile, which represents knowledge and light. … It’s a testament to the power to change things.”

Contact Jack Austin at [email protected] and follow him on Twitter at @JackAustinDC.