For GSS Losing Biodiversity chapter 6. Excerpt: Not long ago, Berkeleyside reader Patrick Hickey kindly sent in a photo of a beautiful bird of prey, perched on a tall building near his home in downtown Berkeley. ...Rusty Scalf, teacher and trip leader for the Golden Gate Audubon Society, confirmed it: the bird was a peregrine falcon — the fastest animal on Earth. In California, not long ago, it was also one of the most endangered. ...“Many of us were looking at the extinction of the peregrine in the 1970s,” said Glenn R. Stewart, director of the Santa Cruz Predatory Bird Research Group (SCPBRG) . “It really looked like they were going to be gone forever.” At that time, Stewart and other scientists could find only two pairs of peregrine falcons in California. In the eastern part of our country, peregrines were totally gone. ...The pesticide DDT — widely used in the 1940s, 50s, and 60s— accumulated in the fatty tissues of peregrine falcons (and also, bald eagles), causing these birds to lay thin-shelled eggs that broke in the nest during incubation. With the banning of DDT in 1972, and decades of impassioned work by Stewart and the SCPBRG, peregrine falcons have undergone a near-miraculous recovery. Today, an estimated 250 to 300 peregrine pairs are living and nesting in California, a number  that Stewart believes approximates original pre-DDT populations. “The interesting part of the peregrine’s tale is their adaptability to the urban environment,” says Shirley Doell...a peregrine volunteer — a “citizen scientist”— who ventures out at dawn nearly every morning in spring, plus some evenings, to monitor pairs of peregrines on skyscrapers, high-towered bridges, and tall industrial cranes in the East Bay. ...“Most endangered species can only live in a particular niche in a particular kind of habitat,” Doell says. “But the peregrines don’t seem to mind the bustle and noise of the city, if there are tall structures and birds around for them to catch.” ...In cities like Berkeley, Oakland, and San Francisco, peregrines hunt pigeons for about 90% of their diet. ...“And living in a place like downtown San Francisco, where there’s an abundance of pigeons… it’s like living on a remote island in British Colombia with an abundance of sea birds nesting. Only here, the cliffs happen to be buildings, or bridges. The food happens to be nonnative pigeons.”.... See also San Francisco nestcam  and San Jose nestcam. By Elaine Miller Bond. Berkeleyside. http://www.berkeleyside.com/2014/04/29/friends-in-high-places-peregrine-falcons-soar-above-us/