Common Names: Monk Parakeet, Quaker Parakeet, Quaker Parrot, Quaker Conure, Grey-headed Parakeet The natural distribution of the Monk Parakeet (Myiopsitta monachus Boddaert, 1783) extends from southern Bolivia, through Paraguay, southern Brazil and Uruguay to southern Argentina (Fig. 10.1 ). It is documented as invasive in a range of countries, and of these, there are at least 17 countries where they are breeding in the wild, as detailed below. . The Monk Parakeet is among the most successful invasive bird species in the world. Unlike many other invasive birds, such as the Ring-necked Parakeet (Psittacula krameri) and the Common Myna (Acridotheres tristis), there is no evidence that invasive Monk Parakeets compete with or otherwise negatively affect native species. Their economic impact on agricultural crops has been limited to date, but reports from Spain (Senar et al., 2016) and Israel (Postigo et al., 2017) suggest that serious problems might be developing in some countries. The unique nest-building behaviour of Monk Parakeets does create serious problems for electric utility companies (Avery et al., 2006) and in at least one instance prompted an eradication effort (Godbeer, 2014). Several factors contribute to the success of the Monk Parakeet as an invasive species: