Many electroacoustic devices can be simulated, but if you purely refer to musical instruments, you should be talking about bird whistles. This was the earliest whistle that could be held in the mouth to imitate bird calls to attract birds for hunting. Its function is as a hunting tool. If there are other unplugged musical instruments that can imitate bird sounds or the chirping of birds and insects, and can produce sounds that are very similar to bird sounds, this should be the only one.