Cobalt-winged Parakeet
Brotogeris cyanoptera
The cobalt-winged parakeet is 18 to 20 cm (7.1 to 7.9 in) long and weighs an average of 67 g (2.4 oz). The species is almost entirely green that is darker on its upperparts. Adults of the nominate subspecies B. c. cyanoptera have a yellowish forehead, an orange chin, and a blue tinge on their crown and nape. Their flight feathers are blue; their central tail feathers are also blue and the rest are green. Immature birds are a duller version of the adult. Subspecies B. c. gustavi has very little blue on its head and a yellow edge on the carpals. B. c. Voice: The cobalt-winged parakeet's common calls are " a high-pitched "klee", shrill "chree" or bisyllabic "chree-chree"" that are given both when perched and in flight. Another call is "a fast chattering series "chichichichichi"." Members of flocks call simultaneously and make "a shrill chattering".
ID text from Wikipedia, CC BY-SA 4.0

Plain Parakeet
Brotogeris tirica
The plain parakeet is 23 to 25 cm (9.1 to 9.8 in) long and weighs about 63 g (2.2 oz). Adults have an essentially all green body, though their nape has a bluish tinge and their undersides have a yellowish one. Their shoulder is bronzy or brownish green and their flight feathers and the underside of their tail are bluish green. Their bill is pinkish with a paler base. Immature birds are similar to adults but with less blue in the wings and a shorter tail. The population in São Paulo state has many individuals with a blue mutation. Voice: The plain parakeet's calls include "a rather high-pitched shrill "cree" or bisyllabic "cra-creep", and a lower-pitched, harsh-sounding "cra-cra-cra"" that are given both from a perch and in flight. Members of a flock often call simultaneously.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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Play today's Daily BirdPhotos and recordings are credited to their authors under the licence shown. Full profiles: Cobalt-winged Parakeet and Plain Parakeet.