Figure 52.7 Sensitive Periods for Song Learning (A) Sonogram showing the species-specific song of an adult male white-crowned sparrow (Zonotrichia leucophrys). (B) Song of an adult male raised in isolation (never having heard the song as a nestling). (C) Song of an adult male that heard the song as a nestling but was deafened prior to ever singing himself. Experiments showed that the bird must first acquire a song memory by hearing the song as a nestling, and must then be able to hear himself as he attempts to match his singing to that song memory.