There are several species of parakeet present in European cities alongside the Rose-ringed, or Ring-necked, Parakeet, Psittacula krameri, also known as the Kramer Parrot. The others are Blue-crowned Parakeet, Thectocercus acuticaudatus, the Alexandrine Parakeet, P. eupatria, and the Monk Parakeet, Myiopsitta monachus. If we’re talking parrots in general, there’s also the Common Parakeet, perhaps better known as the Budgerigar, Melopsittacus undulatus.
The Rose-ringed Parakeet is well known in city parks and green spaces with trees across Europe from Athens to Amsterdam, Barcelona to Bonn, and Lisbon to London, and even as far north as Newcastle. The common sub-species in those cities is native to Africa but has adapted successfully to living in disturbed and urban habitats having escaped deforestation. Their presence in London has nothing to do with an imagined publicity stunt by Jimi Hendrix.
Rose-ringed Parakeets were and presumably still are a popular pet bird species and so escapees have fed into the feral populations. It is naturalised in many places now, breeding as if native. But, it is considered a pest in places where the sub-species in India has bred into massive colonies, but in Europe there does not seem to be a need to cull them. Peregrines, Hobbies, and Tawny Owls will all predate Rose-ringed.
Meanwhile, the Blue-crowned Parakeet is a native of South America. It is generally found from eastern Colombia to Curaçao in the southern Caribbean to the northern parts of Argentina. It prefers savanna-like habitats, woodland, and forest margins and so is generally not present in dense, humid forest like the Amazon. Introduced, as one might expect, to the USA, specifically south Florida, California, and Hawaii. It is now present in several cities across Europe too, Barcelona, Lisbon, Milan, Paris, Zürich, and on the Canary Islands.
A Blue-crowned Parakeet nest with eggs, subsequently predated, was observed in 2001 in Lewisham, southeast London.