The nominate race, M. monachus monachus, is the most commonly available subspecies. A medium-sized bird measuring 11-12 inches in length, the upper parts of the bird are almost all green, with shades of medium green on the back and brighter green on the wings and tail. The lores, cheeks and throat are gray, merging into pale gray, white-tipped breast feathers. These breast feathers merge into a grayish, olive-green lower abdomen. The feather edges on the chest are very distinct, giving the gray area a scaled appearance. There is a suffusion of yellow on the thighs and underparts.
The flight feathers are blue, edged with black. The under wing coverts are pale gray and pale blue. The tail is long, narrow and green, slightly tinged with blue, and edged with black. The bill is horn colored, and the eyes are brown. Immature birds are not as quite a bright green in color. Their heads are a dull green, and the flight feathers are more green than blue. The Quaker is similar in length to a Cockatiel, but a Quaker’s body is heaver, stockier, and more substantial with an average weight of 90 to 120 grams. Young birds look much the same as adults although their coloring is not as bright. The native habitat of this species is extreme southeastern Brazil, through Uruguay to northeastern Argentina.
Myiopsitta monachus luchsi
The Bolivian gray-breasted parakeet (Myiopsitta monachus luchsi) resembles the nominate race except that the forehead and fore crown are a very pale gray, almost white. The breast is uniformly pale gray without any scaled appearance. The upper abdomen is a purer yellow, and the other webs of the primaries are a pale blue without the green margins. The tail is dark green with blue down the center of each feather and is grayish blue underneath. This bird is a little smaller and narrower, with a more pointed bill. It is found only in central Bolivia, in the Cochabamba province.