chant (noun / verb) - a repeated, rhythmic phrase, typically one shouted or sung in unison by a crowd; to shout a word or words repeatedly.
chanting (adj.) - when something is shouted in a repetitive manner.
"The chants energized the audience." (noun)
"What is the crowd chanting?" (verb)
"The hockey team chanted 'Win! Win! Win!' before the game started." (verb)
"The chanting fans echoed throughout the stadium." (adj.)
As someone else mentioned, you want to use 'chirp' for the brief sound that birds make :)
"The bird chirped loudly this morning."
"The chirping birds are music to my ears."