The Clever “Karasu”: Wise Old Birds Living Side by Side with Humans

Society

They scatter the streets with trash yanked from garbage bags and attack passers-by. There seems no end to the ills attributed to karasu, the crows and ravens of Japan, where their image in the popular mind is far worse than that of any other wild bird. Yet these clever birds know that close to humans, they will never want for food and places to live. A longtime observer of these birds’ behavior and ecology reveals their secrets.

Smart Enough to Be Dangerous

All these aspects of karasu crows and ravens have earned them the nickname “the feathered primates.” It is exactly because they are so intelligent that they can behave in ways we would never have dreamed of. Meanwhile, their diversity and flexibility enable them to adapt to our own complicated lifestyles, so much so that even when we find ways to counter one set of problematic behaviors, they will likely bounce back in ways that are even harder to counter than before.

ashibuto karasu jungle crows like meat even more than their hashiboso carrion crow brethren do. With the discarded food available in cities, the buildings and other constructions that take the place of trees, and the absence of any raptors, their natural enemies, urban jungle crow numbers have soared.
Hashibuto karasu jungle crows like meat even more than their hashiboso carrion crow brethren do. With the discarded food available in cities, the buildings and other constructions that take the place of trees, and the absence of any raptors, their natural enemies, urban jungle crow numbers have soared.

Compared to other birds karasu have very highly developed brains. Their ratio of brain mass to body weight is 1.4%, ten times greater than the 0.12% ratio of chickens. This places them vastly closer to humans (1.8%) than to their poultry relatives. Their ability to predict where cars will pass and place nuts there so the tires will crack the shells open, and to reposition the nuts if their first estimate was incorrect, is just one manifestation of this. It is no doubt because of this intelligence that they knew from ages past that they would never want for food or shelter so long as they lived nearby us. Even as our own lifestyles have been transformed, they have been able to adapt and keep pace. The more our production efficiency rises, the more surpluses we create, the more food and housing materials are left over for them, and the more their numbers increase.

At the time of Japan’s high-growth period up through the early 1970s, it is estimated that approximately 37,000 karasu lived in metropolitan Tokyo, flocking around the garbage mixed with drifts of leftover food dumped in the back alleys of the city’s downtown districts. The crow problem peaked around the turn of the century, and various countermeasures were put in place, including moving garbage collection times to the middle of the night before the karasu were active, making the people generating garbage take responsibility for separating it out into different categories themselves, and more. These measures have proved effective, and today the number of karasu living in downtown urban districts has fallen to a third of what it was before. The number of public complaints is only a tenth of what it was at the time, and crow-human relations have improved somewhat. However, it took 20 long years of effort to bring us to where we are today.

Once the delicate balance between human beings and wild animals has been lost, it is no easy task to reestablish a way for us all to coexist together. All creatures living in the wild must constantly hunt for food to eat, and once they find a reliable source they are unlikely to abandon it. I believe it is the duty of we humans, always so prone to disrupt the natural balance, to decipher the behavior patterns and habits of these intelligent birds, and seek out a wiser way for us all to live together.

(Originally published in Japanese. Banner photo: A hashibuto garasu jungle crow. All photos by the author.)

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