Mockingbirds are known as some of the best singers in the bird world, and they're extremely versatile. Terry here obviously enjoys birdsong, but many mockingbirds have been known to mimic other animals such as frogs or crickets as well as man-made machines and electronic devices. They also enjoy doing much of this singing while most of humankind (and Jim the mockingbird kind) are asleep. It can be annoying, but I still have a hard time getting mad at a mockingbird singing his heart out.