Aratinga erythrogenys is native to the coastal dry regions of western Ecuador and extreme northwestern Peru and (Best and Clark 1991, Best et al. 1993, 1995). It is considered a restricted range species of Near Threatened conservation status (Mace and Stuart 1994, Birdlife International 2004), since its distribution pattern appears to be limited and closely tied to the arid and semi arid habitats (Best and Clark 1991, Best et al. 1993, 1995).
A. erythrogenys presence/absence pattern in certain areas is reported to be seasonal, this is probably connected with food availability and/or the nesting season (Best et al.1993, 1995; Chavez-Riva 1994). Marchant (1958) states that "on the Santa Elena Penninsula, south western Ecuador, non-breeding flocks were present from April through August 1957", and then absent for the remaining calendar months. Nesting parakeets are absent from traditional nesting locations outside of the nesting season (Chavez-Riva 1994).
In Ecuador Red-masked Parakeet primarily occurs below 1300 m, but occurs "occasionally or seasonally" up to 1900 m, and "locally (and perhaps only infrequently)" up to 2500 m (Ridgely and Greenfield 2001); in Peru the distribution is mostly below 700 m, but locally Red-masked Parakeet occurs up to 1700 m (Schulenberg et al. 2007).
Distribution outside the Americas
26,375 and 16,767 wild A. erythrogenys, were imported into the United States between 1981 to 1985 (Traffic 1987) and 1988 to 1990 (Collar 1997), respectively, from their native Peruvian and/or Ecuadorian ranges. Others were exported to Europe and elsewhere. Some of these imported birds escaped or were intentionally released by their owners. These escapees survived and established small sedentary populations usually in urban areas, both within the Americas and outside of the Americas. At the time of this writing, in addition to having populations on two Hawaiian Islands, A. erythrogenys also has become naturalized in the cities of San Francisco, California, U.S.A.; residential neighborhoods in the San Gabriel Valley and Redondo Beach of Los Angeles County, California (Garrett and Mabb 2004); and in the city of San Diego, California and the suburban areas of Miami-Dade County, Florida, U.S.A. (Pranty and Garrett 2003); Grand Cayman Island; Greater Antilles (Forshaw 2006); possibly Puerto Rico (Mark W. Oberle, personal communication); in southern Spain (R. Jonker, personal commication); and in Lima, Peru (Schulenberg et al. 2007).
Aratinga erythrogenys is a bird of the coastal dry regions of western Ecuador and extreme northwestern Peru and (Best and Clark 1991, Best et al. 1993, 1995), formally known as the Tumbes/Piura tropical dry forest ecoregion (Best and Kessler 1995). It occurs "chiefly in large valleys" (Marchant 1958), desert with cacti, acacia scrub, thorn forest, deciduous and semievergreen forest, premontane and lower montane forest, usually below 1000 m but brief forays up to 2500 m (Best and Clark 1991, Best et al.1993, 1995, Best and Kessler 1995). This ecoregion has a distinct dry season and a wet season between November and May (Best and Kessler 1995). Mean annual rainfall in the forest types it is found can vary from 100 to 2500 mm (Best and Kessler 1995) with average annual temperatures of between 24 and 27º C. (Pulgar 1967). Dominant native tree species within the native range of Red-masked Parakeet A. erythrogenysare Prosopis pallida and Prosopis juliflora (by some considered to be the same species; Landeras et al. 2005), Leucaena trichodes, Ceiba pentandra, Tabebuia billbergii (Ferreyra 1988, Rodríguez 1996), Pithecellobium excelsum, Erythrina velutina (Best and Kessler 1995), Acacia tortuosa, and Celtis iguanea (Weberbaur 1945). The trees Ceiba trichistandra, Eryotheca ruizii and shrubs Cordea lutea, Zanthoxylum montaro, and an unidentified Leguminosae always were present in nesting habitat (Chavez-Riva 1994).
None reported, other than the establishment of feral populations outside of the original distribution (see Distribution: Outside the Americas).