As the crow flies: A bird’s eye view of Japan’s urban ecology

On an unusually balmy day in December, Koichi Karasawa and 53 volunteers for the Urban Bird Society of Japan gathered for their eighth survey of Tokyo’s crow population.

Equipped with binoculars and notebooks, the party split into smaller groups to observe the number of avian pests roosting at Meiji Shrine, Toshimagaoka Cemetery and the Institute for Nature Study botanical gardens — all located within the capital’s 23 wards. By nightfall, they had counted 2,785 — the lowest figure tallied since the research project commenced in 1985.

“It’s the pandemic,” says Karasawa, a soft-spoken, 78-year-old retired high school biology teacher. “With many Tokyoites refraining from dining out and restaurants shortening business hours, the amount of garbage for crows to feed on has fallen drastically,” he says.

“With so few around now,” he says, “perhaps people won’t hate them quite so much.”

‘Crow pies’

If humans are at the apex of one end of the urban ecosystem, crows would be at the other end.

That’s a line from a 1988 book titled “Why the Crow is So Smart” penned by Karasawa, who has been tracking the population of Tokyo’s once-ubiquitous corvids for nearly 40 years.

During that time, the nation’s economy went from boom to bust before sinking into a deflationary spiral it has yet to emerge from. The number of crows spotted in the world’s largest city has followed a similar trajectory, says Karasawa, a well-known ornithologist who founded the Urban Bird Society of Japan in 1982.

“They’re a barometer measuring our society,” he says. “Through them, we can learn about what has happened in Japan over the past several decades.”

The Tokyo Metropolitan Government says the breeding of crows, called karasu in Japanese, was rarely seen inside the Yamanote Line — a circular rail line running around central Tokyo — during the 1970s. But as the nation became richer and society more opulent, so did the contents of the garbage bags the beady-eyed birds target.

When Karasawa and his organization conducted their inaugural census in 1985, they counted a combined 6,737 at three known communal roosts in the capital, where crows gather during the fall and winter months when food gets scarce. They’ve since surveyed at the same locations every five years, and the results have been telling.

In 1990, the group observed 10,863 and, in 1995, 16,157. By 2000, the number of crows they saw at the three spots hit an all-time high of 18,658.

“We analyzed the reason behind this growth, and came to the conclusion that it had to do with how the Japanese lost their frugality and embraced mass production and consumption as the nation prospered,” Karasawa says.

Indeed, by the time the asset-price bubble burst in the early 1990s, Japan’s economy had reached unprecedented heights. In an era of excess and exuberance, nightly parties and overspending were the norm.

“That also produced massive amounts of garbage, which attracted crows,” Karasawa says. “And that consumerist ethos prevailed well after the bubble burst and the economy slumped.”

By the turn of the millennium, crows appeared to be everywhere — swooping down on pedestrians, nesting on utility poles and ripping open garbage bags to scavenge for food scraps.

The Wild Bird Society of Japan estimated the city’s crow population in 2001 at around 36,000. Some even attacked people, especially during nesting season from spring to early summer.

Municipal authorities were receiving thousands of complaints from citizens fed up with the birds' antics and their terrible cawing. Something, they said, had to be done.

And so Tokyo’s famously rambunctious governor at the time, the late Shintaro Ishihara, declared an all-out war against crows, even suggesting a culinary solution to rid his city of the ornery birds.

“How about making crow pies Tokyo's specialty,” he said during a news conference.

Crow traps were set up at dozens of locations, mostly in parks and other green spaces. Crow nests were knocked down to control breeding. Citizens were asked to separate their trash and garbage was covered with nets to prevent the animals from reaching the goodies.

“Traps and better garbage management have been the central pillars of our efforts to manage the crow population,” says Motoi Sato, an official at the city government’s Bureau of Environment.

These initiatives proved effective, and the number of crows observed in Tokyo gradually declined. In 2020, the city counted an estimated 11,000, less than a third of its peak population.

“Still, it’s clear as day that these figures would rebound immediately if we halted these measures,” Sato says.

Concrete jungle

There are five species of the Corvidae family seen in the Japanese archipelago. Of them, the hashibuto garasu, or the jungle crow, and the hashiboso garasu, or carrion crow, are seen all-year round. While similar in appearance, the jungle crow is larger and has a thick beak, while the carrion crow has a short, narrow beak and a croaking caw.

As its name suggests, the jungle crow’s habitat mainly consists of forests, but in recent decades many have made their ways into the concrete jungles of Tokyo and other large cities. Their cousin, the carrion crow, meanwhile, features more widely in rural areas with open space for foraging.

These winged omnivores eat almost anything, and are known for their high level of intelligence, says Naoki Tsukahara, a specially appointed assistant professor at Utsunomiya University in Tochigi Prefecture who has been studying crow vocalization.

Tsukahara is also the founder of CrowLab, a firm specializing in deterring crows through recordings of caws. While the population of these birds may be falling in Tokyo, they remain one of the most destructive pests in agriculture, topping the list of harmful avian crop-raiders in most prefectures. In fiscal 2018, for example, such damage amounted to ¥1.3 billion, according to the agricultural ministry.

“So far we’ve succeeded in keeping crows away by playing recordings of their alarm caws,” Tsukahara says. “But they’re smart, so we need to play a variety of cries from a variety of situations to keep them from getting used to the sounds.”

An orchard in the Hokkaido town of Ikeda, known for its Tokachi brand of wine, for example, lost around 90% of its grapes to crows in fiscal 2019. The following year, CrowLab installed eight speakers across 4 hectares of vineyards and successfully protected most of its harvest. The company leases its sound reproduction apparatus for ¥55,000 a month per hectare of farmland.

Tsukahara says that while Tokyo has been killing the thousands of crows that get caught in crow traps each year, their impact on the bird’s population may be subtle.

“Most that get entangled are fledglings, not breeding-age crows,” he says. “So when Tokyo sees its crow population decrease, it’s more likely to be the result of garbage-related measures such as door-to-door pickup and nighttime collections.”

The pandemic has also seen the amount of garbage produced by restaurants and offices plummet, as states of emergency limited business hours and many firms adopted remote work to lower infection risks.

Ryohei Sueki, an official at the Clean Authority of Tokyo, an organization managing the capital’s incinerators, says that compared to the previous year, the amount of burnable garbage coming from the city’s restaurants and corporate offices in fiscal 2020 fell by 25% to 738,350 tons.

“These include paper waste from office buildings and raw garbage from restaurants,” Sueki says.

But while the health crisis may temporarily limit the volume of trash produced by Tokyo’s commercial districts, that could easily be reversed once pandemic-related restrictions are completely lifted and the service industry gets back on its feet. In that event, it likely won’t take long for the birds to return to their old stomping grounds.

“At this stage, we know how to keep crows away. But we’re also experimenting with methods to guide the birds to our locations of choice,” Tsukahara says. If that becomes possible, crows could be directed to areas where they won’t be a nuisance for both city dwellers and suburban and rural farmers.

Crows are synanthropic animals, however, benefiting from human interaction and the habitats — and leftovers — people create. That means sending them out into the sticks may not be a permanent solution.

Venerated and vilified

In the “Kojiki” and “Nihon Shoki,” the oldest texts on classic Japanese history, a giant three-legged crow known as the yatagarasu appears.

Considered a god of guidance and the incarnation of the sun, there are still shrines that deify the divine crow, and the yatagarasu is considered a symbol of the Kumano region in the Kii Peninsula, for example, an area known for being home to an ancient pilgrimage site.

“Crows and humans go back tens of thousands of years,” says Hajime Matsubara, an affiliate assistant professor at the University of Tokyo’s museum.

“They appear not only in Japanese mythology, but in legends handed down by hunter-gatherers in Eurasia and America,” he says.

Despite its revered history, crows have suffered an image problem in recent centuries, and have been associated with death and impurity — partly stemming from how, according to records, they flocked around corpses during pre-modern famines.

Japanese superstition warns its caw forebodes misfortune. And its rapid proliferation in cities over the past few decades haven’t helped improve its public perception.

Matsubara has been researching crows for 27 years and has released books on the bird’s behavior. He says that despite its negative portrayal in mass media, humans are responsible for its population growth. In fact, he says, the government’s forestry policy may have expanded its habitat.

After spending years studying crows in urban and suburban settings, Matsubara has been focusing on tracking jungle crows in Japan’s mountains and forests — an arduous task considering the wide range of woodlands the species roam over. Still, he has discovered some important hints involving its ecology.

“Crows seem to prefer coniferous forests over beech forests,” he says. “Jungle crows often nest on branches of evergreens.”

Japan’s forests have undergone a massive transformation over the past century. Vast portions were cut down during World War II to support the military, and after the war, a spike in demand for timber to feed reconstruction needs saw even more woodlands disappear, prompting the government to launch a nationwide reforestation campaign.

Millions of hectares of beech trees were wiped out and replanted with fast-growing conifers such as cypress and cedar, which now account for around 40% of the nation’s forests.

“We talk about how our garbage attracts crows. But I find it even more ironic that we’ve been creating a habitable environment for them by destroying our woodlands and planting conifers,” Matsubara says.

Despite its negative representations in popular culture, crows have drawn countless enthusiasts over the years, including Karasawa, who has spent the best part of his life studying the animal.

Part of the bird’s allure lies in their unusually large brains that allows them to, for example, drop nuts on roads to have them crushed by cars. They can fashion tools from pieces of wires and sticks to reach grubs, and are known to have an uncanny memory of human faces.

That advanced cognitive ability may be what makes crows both fascinating and fear-inspiring.

“We need to reflect on what we’ve done,” says Karasawa, who embarks on frequent bicycle trips to monitor his avian friends in the city.

“Shintaro Ishihara vilified crows, but we’re the ones who have been responsible for their livelihood,” he says. “If we can accept and learn from that fact, I think it’s an improvement.”