Campus & community, Campus news, Science & environment

Cal’s main attraction? For nesting peregrines, it’s the Campanile

Avid falconer Doug Bell, who has been monitoring the falcon pair, thinks hatchlings may be getting ready to fly soon

peregrine in flight with prey
A peregrine brings back a pigeon for her chicks to eat. (Photo by Mary Malec)

When Doug Bell heard that a pair of peregrine falcons was nesting on the Campanile, he couldn’t believe his luck. An avid falconer, Bell has been fascinated with peregrines — the fastest animal in the world — since he was a kid growing up in Berkeley. He received his Ph.D. in zoology from UC Berkeley, where he studied ornithology and systematic biology. But never before had he heard of peregrines nesting on top of the campus’s 300-foot-high bell tower. “It blew me away,” he says.  

The female peregrine falcon on the second balcony ledge of the Campanile, close to her nest (Photo by Doug Bell)

Bell, now a wildlife program manager with the East Bay Regional Park District, says peregrine falcons were once on the brink of extinction, in large part caused by the widespread use of the pesticide DDT and the country’s misguided assault on predatory animals. In the early 1970s, however, peregrine falcons caught a break. DDT was banned and the Endangered Species Act was passed, among other wildlife regulatory laws. In the years since, peregrines have made a remarkable comeback.

As the numbers of peregrine falcons have increased, they’ve begun moving from their natural cliff faces into urban areas, laying their eggs on skyscrapers and other tall buildings, such as the Campanile. Berkeley News spoke with Bell about the Campanile’s first-known peregrine falcon family, and how the top-speed bird has soared back from the brink of extinction.

Berkeley News: When did you first hear about the peregrine falcons nesting on the Campanile?

Doug Bell: I first heard about them in early April. [Amateur birdwatcher Kathleen Durkin, who runs a computing lab in the College of Chemistry, first spotted them. Listen to the audio she captured below.]

I thought, gosh, you know, I want to check it out. So on the weekend, I was watching them and it sure looked like they were nesting there. Falcons don’t build nests — they just use a substrate like soil or gravel and make a little depression in it. That’s nice for cliff faces, where they nest in natural situations, but for buildings and skyscrapers that just have cement or steel, there may not be enough substrate around to cradle the eggs, so the female can’t incubate them well. I thought, “We gotta get something under those eggs, so they at least have a good shot at incubating.”

Where are they, exactly? 

[Mary Malec, a volunteer raptor nest monitor for East Bay Regional Park District who has been regularly watching the birds, answered this question.] The nest site is on the west-facing side of the second balcony above the carillon bells. The nest area isn’t visible from the ground from any place we’ve been able to find — it’s too high up and deep behind the balcony. The adults sit regularly on the base of the corner spires — sometimes on the balconies of their nest level, sometimes on the top of the Campanile.

peregrine eggs in sand

The female peregrine ripped open a sandbag to lay her eggs. (Photo by Mary Malec)

What did you see when you went up to check on them?

Doug Bell: When we first appeared around the corner, the female peregrine walked off her eggs for about five feet, turned around and stared at us, like, “You want a piece of me?” She had tried to lay her eggs in sandbags that maintenance had put up there to divert rainwater from the building. She had ripped apart a sandbag, put her three eggs there. They were very wet because of all the rain. I brought up a shelf — about two feet by two feet — with drain holes and filled with gravel. We placed the eggs in a little depression for her. We left and went back inside the cupola to watch, and within 10 minutes she came to the new nest box, stepped up onto it and scraped in the gravel. By the time we left she was standing over them. So now it looks like we’ve had hatch, which may not have been able to happen had we not put in the shelf.

doug bell installing new nest site

Bell replaces the makeshift sandbag nest site with a shelf filled with gravel, closer to a nest site that a peregrine would use in the wild. (Photo by Mary Malec)

So, is there evidence that the chicks have hatched?

We don’t know for sure, but we’re fairly certain they hatched around May 22. There is a group of peregrine watchers that are regularly checking on them with binoculars, taking notes. On May 22 the peregrines were spotted taking food to the nest site, so that means they’ve probably hatched. We installed the nest shelf on April 21, and incubation usually takes somewhere around 30 to 32 days, so there you have it. I will put in a request soon to band the chicks in about three weeks. When we go up, we’ll know how many chicks there are and have a better idea of what’s going on. Accidents happen, and predation happens. Things like great horned owls eat peregrine babies, so you just never know what could happen. Nature happens, you know? So we could still lose the effort, but we hope not.

When will the hatchlings start to fly?

Nestlings fledge about 38 to 42 days after they hatch. That means they’ll start flying around. They’re in a good position where they can run all around the Campanile, so that’s good. They’re kind of blocked by the banister. It’ll be like a big baby pen for them, in a way. They’ll be able to exercise their wings really well. Sometimes what happens, especially in urban environments, if they’re in a tight spot, they’ll jump. At some point, nature tells them, “You gotta fly, kid.” And it can be tricky in city environments because they may, you know, fly down 30 stories to the city streets and then they’re at risk of getting run over. Or getting confused. They might not be able to get back up because it’s their first flight. They need to rest a bit.

peregrine in flight with prey

The female peregrine kills and brings back a pigeon to the nest, which Bell says is a sign that the chicks have hatched. (Photo by Mary Malec)

Do humans ever intervene in fledging situations?

A lot of city peregrines have watches where people watch them and if they fledge, they’ll gather them up, make sure they’re okay, haven’t broken anything, and then they’ll put them back. Usually by the second or third attempt, they’re good — they can get over to another city roof, skyscraper roof or something like that. So the campanile birds, they’re in a really good situation. There are a lot of roofs they can land on, so we think they’re going to be OK. It’s just when one goes to the ground where there are a lot of dogs, or on the glade where students are playing around next to the campus library. You know, it’d be good in that situation to get them back up so they have a second shot at it. Usually they get their wings by the second flight.

peregrine hatchling

A peregrine falcon hatchling (Photo by Matt MacGillivray via Flickr)

What’s the plan for the Campanile’s peregrine chicks after they fledge?

There has been a group of people who have been watching the peregrines and sharing their notes. A number of folks will probably just try to get together several people who can watch in shifts and kind of keep an eye on things. So we’ll have a good sense. We’ll probably be able to hear and see the chicks running around as they get older. Once they hit 28 to 30 days of age, they’re pretty darn active. They grow from chicks like you might see in a feed store, tiny little things, to gigantic falcons, you know, in 35 days. So with all of us regularly watching them, I think we’ll have a pretty good sense of what’s going on. And then we can ramp up the round-the-clock stuff when it gets close to fledging.

Have they nested on the Campanile in the past?

I don’t know of any nesting attempts. As far as I am aware, this is the first known, confirmed nesting attempt. The thing about peregrines is they like tall structures, and in the winter especially when you get birds coming from up north, or from high-elevation sites, kind of move in to the Bay Area and hang out in what’s known as “overwinter.” It could very well be that this pair was the pair that was overwintering in Berkeley for a number of years, hanging out on the Civic Center building and the Wells Fargo building. This could very well be that pair. They were there for a couple winters in a row, then disappeared. They might have tried to lay eggs on one of the buildings in Berkeley, but that’s all just conjecture. As far as I’m aware, there have been no confirmed nesting attempts on the Campanile.


The peregrines are nesting on the Campanile’s west-facing side of the second balcony above the carillon bells. (UC Berkeley photo by Keegan Houser)

The carillon bells in the Campanile are so loud. Do they pose a risk to the peregrines?

No, I don’t think so because they chose to nest there while the bells are ringing, so I don’t see any issue with it. One critical issue is maintenance needs to be deferred until after the birds have fledged and left the site. If someone unwittingly goes up there and changes a lightbulb or sweeps up the sand from the broken sandbags, it could cause harm to the birds if personnel is unaware of them. If the youngsters were old enough to run around, they might fall and not be able to fly. So basically it’s best to not disturb them. We work with building maintenance people — peregrine people do that all the time — try to advise them when not to clean windows, that sort of thing. [Campanile maintenance has been advised to minimize maintenance in that area until the birds have left the nest.]

Do you have any plans to install a live video feed on the Campanile, like the PG&E building in San Francisco has? [Watch here]

That certainly has been proposed. It’s a great idea, but this year, we didn’t want to add any extra stressors for the birds because we didn’t know if the eggs were fertile or how long she had been trying to incubate them. Certainly for next year, we can plan for something to that effect and maybe put up a more permanent shelf that provides more protection, that sort of thing. Those are things I would certainly embrace and hopefully we could all work together on this to give them a better nesting opportunity. We would also need permission from the regulatory agencies to do that. We can approach them with the subject. It’s not like anyone can go and put a camera on a raptor nest. It’s illegal. You need permission to do things like that.

Are there still regulations in place to protect peregrine falcons?

They are still a fully protected species in the state of California. They used to be an endangered species, but they were removed from the federal list of endangered species in 1999 and from California’s list in 2009. But they’re still highly protected. I had to get special authorization from both state and federal agencies — the California Department of Fish and Wildlife and the U.S. Fish and Wildlife Service — to handle these peregrine eggs and to install the nest shelf.

male peregrine falcon

A male peregrine falcon in a wildlife refuge in Oregon (U.S. Fish and Wildlife Service photo by Roy W. Lowe via Flickr)

Why did they go extinct?

Worldwide, their populations plummeted to very low levels because of the use of DDT and other persistent chlorinated hydrocarbon pesticides. They were laying thin-shelled eggs because DDT interferes with the calcium metabolism. And then predators were pretty much persecuted widely throughout the U.S. all the way up until the 1960s. In California, you could still legally shoot a peregrine up to 1964. In many states, raptors weren’t protected until the late 1960s, early 1970s.

How did they make a comeback?

It’s been a remarkable success story. In 1973, Richard Nixon banned the use of DDT. That’s also the year the current version of the Endangered Species Act came online. So the Nixon administration had actually done quite a bit. The Clean Water Act was passed. A lot of these environmental laws came to be kind of as a result of the ecology movement.

At the same time, there was a big effort undertaken by falconer researchers, like at Cornell University, to start breeding peregrine falcons in captivity, with the thought of eventually releasing them. California had a similar project that started in the 1970s at the Santa Cruz Predatory Bird Research Group at UC Santa Cruz. So they began an intensive nest augmentation program — we still have a few peregrines breeding in the state of California.

Why did they begin to move into urban areas?

It has to do with two things. One, we stopped persecuting them. To a large extent in the old days, back in the 1930s, they would be shot on sight. Hawk Mountain in Pennsylvania, that was a site that was originally set up to shoot hawks as they migrated. They would shoot tens of thousands of hawks every year for fun. Plus, they thought they were doing the world good by getting rid of evil predators. They became protected by wildlife laws as people realized that predators were part of the natural environment.

peregrines nesting in cliff face

A pair of peregrine falcons nesting on Morro Rock in California (Photo by Loren Chipman via Flickr)

Two, cities offer them all that they need. Basically, cities represent a lot of cliff environments. Peregrines are looking at skyscrapers, at the Campanile — they’re like cliffs. And there’s a lot of food around, like pigeons. Peregrines fortunately are a species that forage in the air, so they catch most of their food in the air. [Peregrine falcons are the fastest animal in the world — they can reach speeds of more than 200 miles per hour during dives, killing prey in mid-air.] So that’s very suitable for hunting in cities because there’s not a lot of space on the ground to be hunting, but there are a lot of pigeons in the air and birds in the air in cities. It’s a niche they happily moved into. Probably doesn’t make pigeons happy that they moved in, but that’s another story.