Counting Crows

I am what you might call a zombie bird-watcher. On summer mornings, caught between sunlight and sleep, I drift awake in a haze of coffee and aimless gazing out the window. Half dreaming, I’ll just catch the smug sideways stare of a robin, the purple dart of a finch, the blaze of a passing cardinal.

Then the crows swagger in, all bad attitude and black feathers, and I start paying attention. I’ve asked myself what this means about the way I’ve warped with age. Why, as a dedicated nature lover, do I now prefer the street-gang crows to the graceful finches?

Truthfully, I admire toughness in animals. Too many environmental losses have taught me to appreciate what University of Washington ornithologist John Marzluff calls “the scrappy, noncharismatic species.” The stubborn ones, the smart ones, the adaptable ones. The ones that thrive with us -- and may eventually survive us.

Not all crows are so durable. The Hawaiian crow population now flickers near disappearance. But the continental American crows -- like their Asian and European counterparts -- are a study in success. If you’ve ever wondered about the crow boom of recent years, it perfectly follows our own good times. Rapid urban growth, expanding suburbs, golf courses, fast food -- crows have turned them all into an advantage.

Scientists say my hometown of Madison, Wis., is “saturated” with crows. I can see that through the window. On a given day, I can watch crows chase rabbits, rip apart garbage bags, hunt for earthworms, peel up road kill and quarrel over all of the above -- conducting noisy (and I suspect profane) family arguments. They are completely and confidently at home.

Marzluff has been analyzing the rise of the urban crow. In a book titled “Crows, Ravens and People” that will be published next year, he names other saturated communities. During the 1990s, the crow population of Albuquerque increased 425%. Hartford, Conn., 187%; Sacramento, 122%; Seattle, 57%. Los Angeles probably went up a good 50% in that period, he said, but it was already loaded by the 1990s. My favorite statistic for Southern California comes from Audubon bird-watching surveys in Pasadena -- about 350 crows sighted in 1977, 3,659 by the mid-1990s.

Of course, it’s more complicated than new housing opportunities for crows. What they gain tends to be an accidental byproduct of how we live. And they can as easily lose. Another trait of ours -- global transmission of infection -- recently brought West Nile virus to this country, which has proved dangerous to both humans and crows. By linking their lifestyle to ours, crows take on our risks as well.

That link -- at least in terms of cities -- grew closer in the 1960s. Environmental awareness made it less acceptable to idly kill even the “pest” animals. In the early 1970s, crows were given protection as migratory birds. Until that shift in attitude, said University of Wisconsin ornithologist Stan Temple, crows tended to prefer to keep their distance.

“You don’t see crows really moving closer to people until persecution of crows starts to relax,” Temple said. The birds also discovered that city residents were more tolerant than, say, farmers furious about lost corn. Even now Temple and his colleagues find that urban and rural crows regard people very differently.

If researchers approach a crow nest in the country, the adult birds slip away. “No fuss, no reaction,” Temple said. “It’s the selective behavior of an animal still accustomed to human persecution.” In other words, crows still routinely get shot in the country. But there’s no shyness about urban and suburban birds. When scientists come up on a city crow’s nest, the birds launch a screaming, beak-first assault. Urban crow culture has become, well, urban. Not just in terms of its assertive approach.

City crows tend to be less healthy, scientists say, because they eat more garbage -- in other words, an American junk-food diet. But you can pack a lot of crows into a city because there’s so much food, dumpster-style. A hundred crows may live in the space occupied by one country crow. That allows less room for raising families, though. City crows tend to be mostly young and single. Like their human counterparts, they find the suburbs more family-friendly.

Crows are what scientists call an “edge” species -- they don’t like deep forests or open fields. Insect-rich lawns with the occasional tree are perfect crow habitat. In cities such as Albuquerque or Los Angeles, replacing an arid landscape with the green lawns of golf courses and suburbs served crows almost as well as people. In the Seattle area, taking down forests for suburbs achieved the same effect.

As scientists now see it, the suburbs have become major breeding grounds for crows. The overflow population spills into the urban centers. Crows do raise families in the city, but less frequently. Some adolescent birds spend a year or more in the city, hanging around and living the high life, before returning to Mom and Dad in the burbs. There they take on the role of “helper,” caring for their younger siblings, until they can find a place to begin their own family.

Crows rely on a support network of relatives. University of Washington psychologists James Ha and his wife, Renee, have used a combination of genetic testing and observation to show that crows can identify kids, siblings, aunts and uncles, the whole extended gang. “You don’t see that kind of kinship recognition in cardinals and robins,” James Ha said. “Crows are just really smart, capable birds. They’re right up there with your dog.”

The current question is whether they’re smart enough to adapt to the importation of West Nile virus. West Nile arrived in New York in 1999 and has outpaced the crows in its sweep across the country. The virus is mosquito-borne, indiscriminate and lethal. It kills people, horses and other mammals, and more than 100 bird species, notably the densely packed crows. Because we now live so side by side with crows, they’ve served as a viral signal flare. You can track West Nile by the numbers of dead birds.

The issue for the crow population is which crows? If West Nile is hitting hardest in the city, the virus may be merely taking out the urban overflow and sparing the suburban breeders. If it’s worse in the suburbs, however, crows will lose a major breeding population. James Ha suspects, though, that if the suburbs thin out, the urban crows will move in and replenish. “They’re really good at survival,” he said.

I think crows are really good opportunists -- one of the few species that takes advantage of us more effectively than we do them. With such talents, they should easily survive a mere tropical virus. Between us, not all my neighbors admire this strategic toughness the way I do. But it strikes me that they -- that all of us -- have effectively chosen the crows over the lovely little songbirds of the world anyway. We live a crow-friendly lifestyle, one that almost guarantees that they’ll continue to dominate our backyard bird-watching. So we should learn to enjoy them. Even we zombie bird-watchers can figure that out.