How Japan’s capital put a lid on crow chaos with a ‘simple’ fix

For years, Tokyo residents woke to the sound of crows ripping open rubbish bags, the city’s backstreets strewn with the remains of last night’s dinners. Today those scenes have mostly disappeared, thanks to a 25-year campaign to curb the crow population.\nA survey conducted in December showed the number of crows in Japan’s capital had fallen to less than 20 per cent of its early-2000s peak.\nCity officials and bird experts say the success stems from a mix of civic discipline, careful waste management and a willingness among residents to change their everyday habits.\nIn the 1990s, soaring numbers of the winged scavengers turned Tokyo’s alleys into feeding grounds.\nDrawn to plastic garbage sacks left outside restaurants overnight, the crows learned to rip them open and feast before morning collection. Residents quickly tired of the mess and the menace.\nThe large, intelligent birds also became increasingly aggressive during breeding season, swooping at passers-by and raiding the nests of smaller species.\nParks where the crows roosted were coated in droppings, while the birds’ taste for bright wires and shiny parts led to power outages and damaged fibre-optic cables.\n\nBy 2001, researchers counted a record 18,658 crows at Tokyo’s three main roosting sites: Meiji Jingu shrine, Toshimagaoka Cemetery and the National Museum of Nature and Science. Complaints to the metropolitan government reached into the thousands.\nThat picture has now changed dramatically. In 2024, just 293 complaints were filed, fewer than one-tenth the number at the start of the century.\nKevin Short, a naturalist and former professor of cultural anthropology at Tokyo University of Information Sciences, said the drop in numbers was even noticeable in neighbouring Chiba prefecture, where he lives.\nOfficials employed a variety of measures to counter the crows, from trapping and nest removal to poisoned bait. But Short said it was a simpler measure that ultimately proved most effective.\n“It is simply a matter of better control of garbage and restaurants and other businesses across Tokyo now no longer dump bags on the street at the end of the day,” he told This Week in Asia.\nThe city built communal rubbish stations secured with heavy metal lids, while subtle social pressure ensured public compliance, Short said.\n“And if there is no food for them in the cities, then the crows have gone back to the mountains or the coastal areas that they originally inhabited.”\nOther cities have also taken steps to rein in the crow menace. In December 2010, the city of Minoh, on the outskirts of Osaka, passed a local ordinance that prohibited residents from leaving food out for crows, with a fine of up to 100,000 yen (US$633) for anyone caught feeding the pests or refusing officials access to their gardens to make sure they are following the law.\n\nA Japanese scientist has further turned the tables on the crow population, devoting 20 years of research to recording and deciphering crows’ calls and developing a device that projects warning cries to scare the creatures away.\nDr Naoki Tsukahara is a professor of biosciences at Utsunomiya University who is widely regarded as Japan’s foremost authority on crows. His company, CrowLab, has created a device that can be placed alongside rubbish and uses a sensor to detect when a crow is approaching. The device then plays a recording of a cry that the birds use to warn each other that danger – a cat, hawk or even a human – is nearby.\nTsukahara estimated that he recorded 10,000 crow calls before he was able to isolate those that served as warnings.\nThe equipment was tested in 2023 in Utsunomiya, a city north of Tokyo, and has quickly proved to be effective. Farmers, golf course operators, solar plant firms and warehouse operators are now leasing the equipment, according to CrowLab.\nThe management of a shrine in Fukuoka prefecture has also testified that its surrounding forest was no longer a nesting place for crows.\nShort said the absence of large numbers of crows was also proving to be beneficial to other bird species in big cities.\n“It is good for biodiversity as the hoshi boso crow [carrion crow] has a powerful bill that is designed to tear the meat off dead animals in its normal mountain environment, but they caused huge damage to the sparrow population of Tokyo,” he said.\n“They would raid nests and I myself have seen them swallow a fledgling sparrow whole.”\n