Exodus of the resilient black crow follows flight of other wildlife from Iranian capital Robert Tait, guardian.co.uk 
Tehran’s notoriously bad air pollution has long been a health hazard for its 12 million people, but now the toxic mix of fumes has sent a different set of residents fleeing – the city’s black crows. Environmentalists say the hitherto pollution-resistant population of crows have fled in large numbers in recent days after air quality reached crisis levels. Unregulated urban development has also destroyed the birds’ habitats. The crow exodus occurred less than three weeks after high levels of carbon monoxide and other gases in the air drove off other species of bird, including nightingales and pigeons. Experts fear the departure of the crow – long decried in Iranian culture as a symbol of bad news and gossip – could be the death knell for wildlife in Tehran, where many plants have already lost their smell and colour as a result of the polluted atmosphere. Mohammad Bagher Sadough, the head of the city’s environment agency, said the crow exodus was a sign of a disturbed ecosystem. Eventually the remaining bird species will also leave, turning the city into an urban desert of high-rise buildings and traffic jams. "Pollution is not the only element in the flight of crows and others birds, but it is among the most important," he told the Mehr news agency. "Habitats have been destroyed and the perpetuation of bird life has become impossible.
As the crow flies: birds flee Tehran’s polluted air
