Naturalized Parrots of the World

International trade is recognized as an important and rapidly growing source of introduction of non-native species worldwide (Hulme 2009). Particularly, the trade in wildlife has been directly related to the introduction of non-native, sometimes invasive bird species (Carrete and Tella 2008; Cardador et al. 2019), among which those belonging to the order Psittaciformes play a dominant role (Beissinger 2001; Blackburn and Duncan 2001). The Psittaciformes include parrots, parakeets, lovebirds, cockatoos, macaws, etc., which we collectively refer to as simply “parrots.” Almost two-thirds of all existing parrot species have been commonly transported outside their native ranges as pets, and several more are traded locally (Cassey et al. 2004). This trade has strongly contributed to the decline of many parrot species in their native ranges (Collar and Juniper 1992; Tella and Hiraldo 2014). Nearly one-third of all parrot species are threatened under criteria set forth by the International Union for Conservation of Nature (IUCN 2016), but parrots are also among the most widespread introduced birds in the world (Cassey et al. 2004; Strubbe and Matthysen 2009a; Cardador et al. 2016). Almost one-quarter of all transported species find their way into exotic environments, and at least 10% of parrot species have established naturalized populations (Cassey et al. 2004; Abellán et al. 2017), sometimes with undesirable effects on native fauna and human socioeconomic activities (Strubbe and Matthysen 2009b; Hernández-Brito et al. 2014; Menchetti and Mori 2014; Peck et al. 2014).