Is it true that large flocks of wild parrots can be found in cities such as Los Angeles, New York, and San Diego? When I first heard this I doubted it, since I live in San Diego and I've never seen wild parrots flying around (though I've seen plenty of other strange birds in my backyard.) But apparently parrots are adapting very well to urban environments, and many can now be found living wild in cities throughout the world. It's called Urban Parrot Phenomena. (Actually, I don't know if it's widely referred to as that, but I like the term.)
An article from the IPS News Agency discusses San Diego's urban parrots and their possible origins:
Residents of Ocean Beach believe the parrots arrived 25 years ago after a pet store burned down, and they never left. The seaside community is now home to a flock of 100 naturalised parrots composed of red-headed conures and stubby-winged amazons... Roelant Jonker and Grace Innemee are Dutch biologists who have been studying the phenomena of urban parrots for a while and have a lot of info about the subject on their website, cityparrots.org. You can also view a short clip that Channel 10 news here in San Diego did about the city's parrots. My wife told me that the parrots here in San Diego speak with a Mexican accent, but I think she was pulling my leg.
The true origins of San Diego's city parrots are unknown. More likely than not, they escaped from pet stores, pet owners and even during transport in previous decades when importing wild birds to the United States was part of the legal parrot trade.