By Nicholas Weiler, firstname.lastname@example.org
They’re smart and resourceful — and they’re flocking to Northern California cities in record numbers. They know this is where all the opportunity is these days.
Crows and ravens were once rare in urban areas, but now they seem to be everywhere.
They cluster in parks and scrounge behind dumpsters, cackling and brawling and fixing passersby with calculating stares.
“They’re a nuisance,” said Yvonne Hager, owner of Heather’s Made To Go, a drive-thru coffee shop in Scotts Valley. “They’ve stolen three pastries from me this week!”
But ecologists say it’s time the locals learn to love their noisy new neighbors: Crows and ravens are probably here to stay. These clever birds thrive in our cities because, in many ways, they’re so much like us.
Volunteers in the Audubon Society’s annual Christmas Bird Count first noted a few dozen crows living in San Jose in the early 1950s. Since then the birds have flourished.
By the 1980s, San Jose volunteers were documenting hundreds of crows during the annual daylong count, and in the past five years they have counted an average of 1,200 crows in the city. Bird watchers around the Bay Area and Central Coast have reported the same explosive growth.
When crows first started showing up in Palo Alto in the 1970s, “it was something people talked about,” said Steve Bousman, author of the Breeding Bird Atlas of Santa Clara County and longtime record-keeper for the local Audubon Society. “Now they’re a common bird. I hear them almost every morning.”
The story is much the same for ravens. Raven sightings were almost unheard of outside Marin County until the 1990s, but Audubon volunteers around the greater Bay Area now count hundreds of them each year.
As cousins in the corvid family, crows and ravens can be hard to tell apart at first glance. But ravens are considerably larger than crows, sport thicker beaks and have beardlike tufts of feathers around their throats. Ravens also have deep croaking voices, while crows have a higher-pitched caw. The birds also have distinct social lives. Ravens usually live alone or in mated pairs, while crows are more sociable, often living in large family groups in which elder siblings help parents care for younger chicks.
John Marzluff, a leading expert on crow and raven behavior at the University of Washington, said he sees a great deal of humanity in the corvids he studies. Like us, he said, they are long-lived and form long-lasting monogamous relationships. They are also among the most intelligent of bird species, rivaling many primates with their skillful tool use and ability to adapt to changing environments.
Urban crows have adapted to the human world around them, Marzluff said. In some cities they have learned to use cars to crack tough nuts and wait for walk signals to retrieve their pulverized prizes. They’re also attuned to individual humans. People who feed one crow will soon find themselves followed around by a flock of begging birds, Marzluff said.
And it’s best not to get on their bad side. Eight years ago, Marzluff captured several crows while wearing a caveman mask. To this day, he said, every crow around will scold and dive-bomb him if he ventures on campus wearing the mask.
Even youngsters who weren’t born at the time of the original “crime” had learned to treat the mask as a threat after seeing how older birds reacted to it, Marzluff said.
“The fact that they’re watching us and paying attention to what we do, that’s humbling,” he said. We should see something of ourselves in these smart, social, faithful birds, he said. “This is another form of life out there that’s trying to do the same thing we are.”
KEEP YOUR FRIENDS CLOSE
Crows and ravens have lived close to humans for millennia. The carrion crow haunted ancient battlefields, and early farmers learned to erect scarecrows to keep the birds away from their crops. Ravens in particular are central characters in ancient mythology: The Norse god Odin kept two ravens as his messengers, and native peoples of the Pacific Northwest told stories of Raven the Trickster who created the world by accident.
In the 19th century, crows were actually quite common in the Bay Area, according to contemporary naturalists. But as the land was developed for agriculture, farmers shot them, poisoned them and chased them away. By the early 20th century they were rare outside of rural areas, where they foraged in woods and fields and stole human garbage and crops when they could get them.
But after World War II, as American suburbs spread, crows once again adapted to the changing human landscape. With open spaces for foraging, trees to roost in at night and lots of garbage around, the suburbs were an ideal habitat.
Another big change came in 1972, when crows and ravens became protected under the Federal Migratory Bird Act, according to Kevin McGowan of the Cornell Lab of Ornithology. This meant it was no longer legal to shoot them without a federal permit.
Over several generations, the birds seem to have learned that our growing cities were now safe havens with plentiful food and limited predators, and they began to move to cities en masse.
They may fascinate bird biologists, but the boom in corvid populations has ruffled feathers among wildlife ecologists, who say ravenous ravens in particular are a threat to sensitive bird species like the marbled murrelet, whose nests corvids prey on.
California park officials have attempted to reduce raven populations by trapping and killing the birds, said Portia Halbert, an environmental specialist with State Parks, but the clever corvids quickly learned to recognize and avoid animal-control teams. To take the ravens by surprise, she said, “They have to change trucks. They have to change clothes, change hats.”
Instead, Halbert has spent the past 10 years revamping how the parks handle garbage and educating visitors about the need to eliminate the food scraps that draw ravens there in the first place. She and her teams even begun placing faux murrelet eggs laced with unpleasant toxins throughout the forest, hoping the ravens would learn to avoid them.
These efforts have significantly reduced the numbers of ravens in the parks, Halbert said, but she acknowledged that at this point they are never going to be rid of them entirely.
“They’re here,” she said, “and they’re here to stay.”
As Halbert’s efforts illustrate, crows and ravens have adapted to living with us. Now we must adapt to living with them.