What Does a Northern Mockingbird Sound Like? A northern mockingbird is famous for its remarkable ability to mimic the sounds of other birds, animals, and even man-made noises. Its song is a lively mix of whistles, chirps, trills, and warbles, often repeated several times before switching to a new sound. Unlike many birds that sing only during the breeding season, mockingbirds can be heard throughout the year, especially in spring and summer when males sing loudly to attract mates and defend territory.