Home & Garden Columns

Finding Food Can Be Tough Work for a Falcon By JOE EATON Special to the Planet

Tuesday January 31, 2006

I know: it’s another birds-of-prey column. But when the gods drop a subject into your lap, it would be an act of rank ingratitude not to use it. 

Ron and I were out at the Berkeley Marina a few weeks ago, looking for the burrowing owl that has been wintering on the riprap at the eastern edge of Cesar Chavez Park. She noticed that the gulls in the inlet between the park and the freeway were raising hell about something, and then we saw the big slate-gray hawk with pointed wings flying low arcs above the water, surrounded by a cloud of screaming gulls, and the dead gull below it. We had just missed seeing an adult peregrine falcon make its kill. 

That would have been a spectacle. A hunting peregrine may attain a speed of 155 miles per hour on its final descent (some estimates as high as 273), whacking the prey with both feet, talons curled into fists. I’ve been stooped on by a peregrine, I suspect more out of curiosity than hostile intent, and it was an unsettling experience. One second the bird is a tiny crossbow shape high above; the next, it’s in your face. 

Anyway, that part was over. The problem confronting the peregrine now was retrieval; she (most likely; it was a big hawk, and females are larger than males in this species) had to get the carcass to dry land. She made a few more passes, big yellow feet out like grappling hooks, trying to snag the gull, with the distraction of the living gulls all around her. They weren’t mobbing her the way land birds—crows, ravens, blackbirds—will go after a bird of prey, but they couldn’t have helped her concentration. 

Finally she got it, and made a beeline for the shore. But it was hard work; laborious flapping, with the gull trailing just above the water. And then she dropped it. She flew on, though, and landed right on the paved path for a breather. There were joggers and dogwalkers in close proximity, but this falcon was either habituated to humans or very determined. 

Back to the water again, and again she connected with the gull. 

Back toward shore, into a stiff wind off the Bay. And just shy of the riprap, she dropped it again. This time she flew farther, landing on one of the Monterey cypresses between the park and the Marriott. We thought she’d abandoned the effort, and went on to look for the owl. 

But no. Five minutes later, the peregrine was over the water again.  

For a third time she grappled the gull. She headed west toward land, then suddenly turned south, then west again, as if trying to escape the headwind. Peregrines are not built for cargo hauling, and she was clearly struggling. In the end, she made it: beyond the path, all the way to an expanse of lawn. I felt like applauding. She sat down at once and began to eat; through the binoculars I could see the blood on her beak, and the gull feathers flying. 

Predation, just in case I needed to be reminded, can be hard work.  

Some raptors, like red-shouldered hawks and American kestrels, are sit-and-wait hunters, but peregrines burn energy just looking for targets. Once they’ve killed, they may have to get the prey back to the nest if it’s breeding season, or at least to a secure perch. I looked up the weights for peregrine and California gull in the Sibley guide when I got home; with typical weights of 1.6 pounds for the falcon and 1.3 pounds for the gull, she could have been carrying close to her own mass. 

This would not have set any records; peregrines are ambitious hunters, and have been recorded as capturing prey up to 6.6 pounds in weight: loons, geese, the hulking European grouse known as capercaillies. I got to thinking about relative prey size a bit later after a news story about an anthropologist who has concluded that the Taung child—a famous South African hominid fossil—was killed by a large raptor, forensic evidence pointing to an eagle rather than a leopard or other big cat. Makes sense to me; African crowned hawk eagles prey on good-sized primates, and there’s at least one recent instance of a (nonfatal) attack on a small child. These eagles been known to kill 60-pound antelopes, more than six times their own weight. They don’t even attempt to get airborne with such large prey, though; they dismember it on the ground and cache pieces in trees for later consumption. 

I would like to be able to report that the peregrine at Cesar Chavez Park was left to enjoy her meal in peace. In fact, though, as I was watching her work on the gull, there was a bang and a puff of smoke nearby—some idiot kid with leftover New Year’s fireworks—and she took off. We’ve all had days like that.