Answer:
Just like a seat-belt buzzer, the call is designed to get attention, and fast. During the winter, birds often sing fewer notes, or just one note, to each other. These notes are simply a way to alert the flock of their whereabouts and to announce whether there's any food nearby. 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.
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