The species is native to a broad band across Africa and South Asia, but escapes and releases from the cage-bird trade seeded populations across Europe from the mid-twentieth century. Established colonies now exist in dozens of cities, and the total European population is in the tens of thousands.
Survival relies on the urban setting rather than on cold tolerance. Cities run several degrees warmer than surrounding countryside, supplementary food is available year-round from garden feeders, and mature park trees supply the cavities the birds need. Roosts of hundreds gather in the same trees night after night.
The consequences are argued about. Rose-ringed parakeets compete for tree cavities with nuthatches, starlings and bats, and studies have found displacement at individual sites. Whether this translates into population-level declines in native species is not established, and the strongest documented impacts are on fruit crops rather than on other wildlife.