Alien invaders are infiltrating our cities. Colourful, noisy and clever, they are multiplying rapidly. The rise of the city parrot seems unstoppable. But why are they doing so well in cities, while their rural cousins are struggling to survive? About 50 Amazon parrots live rough on Stuttgarts streets. Theyre not built for the German winter- surviving there takes extraordinary adaptability. But, Stuttgarts Amazons are far from unique. Parrots are appearing in cities all over the world...and theyre doing it in big numbers.