Amid the glistening towers of Tokyo, you'd hardly expect this scene straight from the jungle. Feral Rose-ringed Parakeets, native to the area from the Himalayan foothills to sub-Saharan Africa, gather in raucous mobs in treetops at the Tokyo Institute of Technology, where they loiter from sunup to sundown. These birds are descended from parakeets brought to Japan by the global exotic-bird trade in the 1960s and '70s; initially in fashion as pets, they were eventually turned out by owners who couldn't handle the garrulous, hyperactive birds and their expensive niche appetites. Now their squawks pierce the urban thrum—even through frigid winters, which they somehow endure.
The vibrant plumage of these subtropical natives is a treat for birdwatchers, but as they colonize Tokyo, seemingly for good, scientists are starting to examine their impact on local wildlife and ecosystems. "Our concern is whether or not the parrots are competing for nest sites with domestic species like starlings, or damaging crops," explains Yusuke Sawa, a program officer with BirdLife International in Tokyo.
The situation isn't unique to Japan. Feral parrots have taken up residence in San Francisco, New York, London, and dozens of other cities, where the effects of their intrusion are just as murky. Though many countries have placed heavy restrictions on the import and export of parrots from South America, Africa, and the Indian subcontinent, nearly 2 million birds are still traded every year. The United States and Europe continue to import the birds in large numbers, despite massively expanded regulation on both sides of the Atlantic since the early 1990s. As the global bird trade reawakens, and as more exotics inevitably escape or are released, the consequences are apt to be all over the map.
Correction: This story has been updated to reflect the fact that Rose-ringed Parakeets are native to the entire region from the Himalayan foothills to sub-Saharan Africa.
Editor's Note: Thanks to our eagle-eyed readers for spotting that in the above photo, the bird fourth from the left on the top wire is not a Rose-ringed Parakeet. A consultation with bird expert Kenn Kaufman confirms the suspicion that it is either a Red-breasted Parakeet or a hybrid involving that species.