My Umbrella's probably eat no more than 1-1.5 cups of food per day.
Beeba, my mom's M2, eats about 2 cups of food per day
Gra, my scarlet, used to eat atleast 2 cups of food per day. She was a big girl.
Pua my RLA eats about 1 cup of food per day..she thinks she is a big girl.. lol
Squid, parrotlet, eats atleast 6 tablespoons full of food per day
My cockatiels, each.. probably eat 1/2 cup of food per day
Petrie, lovebird, probably eats 1/3 cup of food per day.
For my big birds, I give them 1/2-1 full cups (each) of veggies/fruits, "fresh" foods, in the morning, a couple tablespoons of pellets, a couple table spoons of seed in their foraging toys, and they "handfed" a mash veggie mix at night, and are given some birdie bread in the afternoon. So it adds up to about 1-1 1.5 cups of food. And they usually dont eat every little bit I give them.
My smaller birds, I just make a full 2 cups of "chopped" veggies, and give them that on a plate, and they eat all of it during the day. They get (together) 1/2 cup of pellets in their pellet dish and 1/4-1/2 cup of seed at night (for 5 birds). And Squid is handfed some birdiemash/formula, at night too.