New Zealand is presented as the setting of P. F. Jenkins’s study of saddleback song, an example of cultural transmission in a non-human species. On islands off New Zealand, the song patterns of neighboring males formed local dialects and passed between generations through imitation rather than genetic inheritance. The observed song repertoire could also change: an imitation error sometimes introduced a new form that remained stable and spread to younger birds. The example makes New Zealand a field setting for the book’s account of culture as a mode of evolution distinct from genetic transmission.

The Saddleback Study

Jenkins studied saddlebacks on an island where the total repertoire consisted of about nine distinct songs. Individual males sang one or a few of them, and males could be grouped by the songs shared within neighboring territories. One group of eight neighboring males, for instance, sang a particular song called the CC song; other groups sang different songs, and some dialect groups shared more than one song.

Comparisons between fathers and sons showed that these song patterns were not genetically inherited. Young males were likely to acquire songs from territorial neighbors by imitation, in a process the book compares to the learning of human language. The island’s repertoire thus functioned as a shared pool of songs from which each young male formed a small personal repertoire.

Song Change and Cultural Transmission

For most of Jenkins’s observations, the number of songs on the island remained fixed. Occasionally, however, a new song arose when a bird imitated an existing one inaccurately. The changes could involve altering a note’s pitch, repeating a note, omitting notes, or combining parts of other songs. Jenkins described these new forms as cultural mutations.

A new song’s appearance was abrupt, but the resulting pattern could remain stable for years. In several cases, younger birds learned the variant accurately, and a recognizable group of singers sharing the new form developed. The sequence links variation to transmission: an error produced a novelty, persistence made it a stable pattern, and imitation carried it into a group repertoire.

Significance in the Book

The saddleback example demonstrates that cultural evolution is not unique to humans. Its songs change through non-genetic inheritance, offering a concrete comparison with human language and other cultural practices. The book distinguishes this relatively limited example from the wider reach of human cultural evolution, which includes dress and diet, ceremonies and customs, art and architecture, engineering, and technology.

The contrast is also one of speed and scope. Language can change across an unbroken chain of speakers at a rate far faster than genetic evolution, while human cultural change may be progressive: the book gives modern science’s improvement over ancient science as an example. The saddlebacks’ local song pool and occasional innovations therefore provide a compact natural example of the broader claim that patterns can be transmitted, altered, and maintained through culture rather than genes.