Eastern rosellas have a striking array of colours. They have a red head and white cheeks. The beak is white and the irises are brown. The upper breast is red and the lower breast is yellow fading to pale green over the abdomen. The feathers of the back and shoulders are black with colored edges.
They pair for life. Pairs court by feeding each other. Breeding season starts in early spring. They nest in hollow trees and lay 2 to 9 eggs per clutch. The female exclusively cares for the eggs. Incubation lasts 21 days, and young fledge after 35 days.
Eastern Rosella parents will preferentially feed their oldest and largest offspring, feeding much less to the youngest and smallest sibling. To compensate for this, the oldest offspring will feed its youngest sibling to equalize their growth rates. When it comes time to fledge, all the babies will be the same size!
They travel in flocks of 8 to 20 birds, looking for seeds, blossoms, berries, fruits, nuts, and leaves.