With birds already being so intelligent, I imagine they could evolve as far as we have. Keeping their bird abilities while obtaining the human abilities as well.
We teach birds "tricks" with small toys imitating human products (ex. small shopping carts) and teach them to talk, though repeating, our language.
Standing more upright , their feathers growing out like human hair, wearing clothes, and their cities with buildings but dominated by trees. This is how I imagine birds being the dominant species!
Inspired by the Florida Tufted Titmouse that lives where I am!