The incessant cawing of big, black jungle crows is one of the most familiar sounds of many Japanese cities, but particularly in Tokyo where, according to one recent survey, the population has exploded from 7000 birds in 1985 to 21,000 in 2000. Whether this is an overall increase or merely reflects a greater tendency for crows to congregate in the city during winter is open to dispute, but there's no doubt that they are perceived as an increasing menace.

In 1999 the Tokyo Metropolitan Government received over five hundred complaints about the birds' behaviour. Their most common offence is scavenging among garbage bags and creating an unsightly mess, but they can also get pretty aggressive, especially during the March-June breeding season. Ueno Zoo lost fifteen prairie-dog pups last year and young children have been pecked on the head, but the most famous victim so far is Tokyo Governor Ishihara Shintaro, who was attacked while out golfing. He has since waged a campaign against the birds, culminating in an emergency task force sent into action over the summer of 2000 to tear down nests and destroy young chicks, with further culls planned.

The real answer, however, is to get rid of the rubbish that attracts the crows to the city in the first place. Since 1994 the authorities in Sapporo have been collecting garbage bags before dawn and then protecting the town's dumps with strong netting. It seems to be working - a recent study of their droppings suggested that the birds were returning to a more natural diet of insects, small rodents and fruit. A number of Tokyo wards have begun to experiment with similar schemes, but until they introduce a city-wide policy, the crows will just descend in ever larger numbers wherever they find easy pickings