I know morse code, I can teach anyone who doesn't know it enough to get messages across.

Crows have the capacity for human speech, too [Fucking Kenny Crow is a godsdamn creeper and a relic of the past but he was based on a sound concept I guess?!]

Larger birds that are strong enough could also use sticks to draw in the dirt a little. But then so could raccoons and opossums and stuff.