Contact calls are used by many animals to locate social companions in crowds and when visually separated. As such, contact calls are often individually unique and can function like names. Wave forms and spectrograms are given for a contact call from each of four nestling Green-rumped Parrotlets (Forpus passerinus) - all siblings. At first you can hear each contact call in normal time. Then you can hear it slowed-down to the point where human ears can distinguish the unique attributes of each nestling's signature contact call.