In winter, urban crows provide awesome spectacle

On a cold November night, my wife and I were walking our dog on a quiet side street in northeast Minneapolis when a cacophony erupted from the canopy of boulevard trees. Mixed in this racket was a cry familiar to every city dweller — "caw! caw! caw!" — followed by a startling spectacle: a crow crashing to the pavement just a few paces from the perplexed dog.

At first glance, the bird looked dead. When I stepped closer, it began to beat its wings and then, clearly injured, it hastily retreated by foot into the darkness. Not wanting to cause further harm (or get pecked by a bird that misunderstood my friendly intentions), I departed. An hour later, I returned but detected no sign of the bird.

Naturally, I wondered what had transpired. And if I believed in augury, I would have no choice but to interpret this odd incident as an omen. While I have long maintained a casual interest in crows, over previous weeks I had been immersing myself in the lore, natural history and growing body of research concerning these ubiquitous birds, arguably Minnesota's most intelligent, nontaxpaying native inhabitant.

People have always known that crows are savvy. Henry Ward Beecher, the 19th century preacher, observed that if humans were equipped with feathers and wings, most still wouldn't be smart enough to be crows. But in recent years, scientists have gotten a much clearer picture of crow intelligence, one that ranks these "feathered apes" alongside primate and cetaceans (whales and dolphins).

In a well-known experiment, a researcher in Oregon donned a fright mask, trapped and then released a crow. Because crows are known for wariness, it was no surprise when the kidnap victim raised a cry of alarm at the subsequent sight of the masked man.

More telling was the response of other crows. While they were generally placid in the busy campus setting, they shouted alarm calls at the sight of the masked man, apparently as a consequence of having been informed of the menace by their comrade.

While science has yet to decode the complexities of crow language, it is now known that the birds "speak" in specific dialects and even employ a separate language with kin. Among their many virtues, crows have a family-oriented social structure and are known to assemble silently around their dead, a behavior some observers characterize as "crow funerals."

Over the past several decades, crows in North America have been adapting in one very conspicuous way: These once rural creatures have been moving into cities in unfathomable numbers, especially during winter when they congregate in huge nighttime roosts.

During the depths of winter of 2010, Sharon Stiteler, author of the popular Birdchick blog and a part-time ranger with the National Park Service, conducted a quick population survey of Minneapolis' so-called "Mega Murder."

"I did it from the bike trail next to the gravel pit off 394 just west of downtown Minneapolis. I counted how many birds were in a tree, then counted the trees," Stiteler said. "Then I counted any more birds that arrived in flocks after sunset." Her estimate of the roost's population? Four hundred thousand birds. In other words, during certain times of the year, Minneapolis is home to more crows than citizens.

There are several theories for the crows' sudden affinity for city living. With the rise of industrial agriculture, many rural areas lack the variety in habitat and foods that crows prefer, perhaps making dumpster-diving a more palatable alternative. The urban heat island effect is thought to be a factor, as is the protection from great horned owls — crows' natural enemy — that is created by the round-the-clock glow of city lights.

Ironically, by moving to cities, crows have also reduced their exposure to their most serious threat — man. Regarded as an agricultural pest and an enemy of favored song and game birds, rural crows have long been subjected to extermination campaigns. During the Depression, the Oklahoma Game and Fish Commission planted bombs in winter roosts and, over a decade, killed nearly 4 million crows.

Conversely, because the discharge of firearms is prohibited in city limits, the crows are safest in areas of dense human population, a lesson they seem to recognize. I like to think that in the future, when we have greater insights into crow language, some bright fellow will discover the crow equivalent to our aphorism, "Keep your friends close and your enemies closer."

Over the 2012-13 hunting season, the Department of Natural Resources estimates that approximately 95,000 crows were shot in Minnesota — an astonishing haul that makes the birds' move to the city look particularly savvy. Lori Naumann, an information officer with the Minnesota Department of Natural Resources, said the DNR has no information on the size of the city's winter crow roost. Because they are so successful, she explained, crows are little studied in Minnesota. But when I related the tale of that mysterious attack on the crow my wife and I witnessed a few weeks earlier, Naumann offered a categorical verdict.

"That was definitely an owl," she said. Apparently, my crow friend had waited a little too long to seek the brightness of, say, nearby Loring Park and the safety of the Mega Murder.