AP BIOLOGY

Detailed explanation-1: -The voice is often the most noticeable form of bird communication. Bird communication using sound includes singing, calls, squeaks, squawks, gurgles, warbles, trills, rattles, gulps, pops, whines, clicks, croaks, drums, whistles, howls, tremolos, thumps, honks and many other sorts of sounds.

Detailed explanation-2: -Birds chirp to indicate danger, warning and communication. Both male and female birds can chirp. The singing of birds is quite sweet and agreeable, often with a melodious tone. In most case, male birds will sing in mating seasons.

Detailed explanation-3: -From my research, I learned that birds chirp to indicate danger, warning, and communication. The birds you hear in the morning are usually males. (https://earthsky.org/earth/why-do-birds-sing2019) They sing to announce that they are alive, alert, and ready to defend their territory.