You see birds flying and searching for food during the day, and the sounds of their chirps let you know they are active. Sometimes you can even hear birds chirping at night! Birds chirp at night for a variety of reasons.
While many birds are daytime birds that need sunlight to see the food they are hunting and gathering, other birds are nocturnal, or active at night. For example, owls hunt critters that scurry about in the nighttime hours, such as rodents. That is why you hear an owl’s hoot after dark. Other birds such as the whippoorwill are famous for their nighttime activity. In fact, the whippoorwill can repeat its loud chirp 400 times without stopping!
Some researchers think that birds don’t need much sleep, and that they would hunt day and night if the darkness didn’t limit their ability to see their food. So in areas where it is lighter for more hours a day, or in places where outdoor lighting helps visibility, you may hear a bird chirping and getting in some extra feeding time!