Parrakeets have been breeding in the Richmond area for many years.
Possibly from pet ones that have escaped, or even been set free on purpose.
In the last few years their population has expanded dramatically, they are spreading over the south of England.
Of course this is totally illegal, the government has decreed it is a crime for any non English species to live and breed in the wild.
And their solution to the problem is ??????
Same as every other crime, ignore it and hope it will go away.