Amazing--from Mandarin Duck wiki.

Specimens frequently escape from collections, and in the 20th century, a large, feral population was established in Great Britain; more recently, small numbers have bred in Ireland, concentrated in the parks of Dublin. Now, about 7,000 are in Britain.[14] Owing to its different habitat preferences compared to native water birds, the mandarin duck appears to have had no negative impacts on native wildfowl as a result of its introduction to the UK, as it does not engage in competition with other ducks over their habitats[15][16] and occupies a previously-vacant ecological niche; it is generally not considered to be invasive. However, its expanding range means that it may compete with common goldeneye (Bucephala clangula), which also nests in trees.[17]

Additional populations of mandarin ducks can be found on the European continent, the largest of which is in the region of Berlin.[18] Isolated populations exist in the United States. The town of Black Mountain, North Carolina, has a limited population,[19] and a free-flying feral population of several hundred mandarins exist in Sonoma County, California.[citation needed] This population is the result of several ducks escaping from captivity, then reproducing in the wild.[10]

https://en.wikipedia.org/wiki/Mandarin_duck