Java sparrow song conforms to Mezerath's Law but not Zipf's Law of Abbreviation

Abstract

Linguistic laws, which describe common statistical patterns in human language, are often studied in animal communication systems. Despite good evidence for adherence to these laws in non-human primate communication, there is still a paucity of data on other taxa. Birdsong is often used as a model for human language development due to similarities in vocal learning processes. Investigating whether birdsong also adheres to linguistic laws may provide further value or help determine the limitations of such comparisons. Here, we looked for patterns consistent with Menzeraths law, the tendency for longer sequences to be made up of smaller constituent parts, and Zipfs Law of Abbreviation, the tendency for more frequently used elements to be shorter in length, in the songs of Java sparrows (Padda oryzivora). We found that songs conformed to Menzeraths law at both the population and individual level; longer sequences were made up of shorter notes. This pattern was achieved through note type selection rather than the shortening of existing note types. Adherence to Menzeraths law may reflect species-specific constraints on song durations. We found no evidence to support adherence to Zipfs Law of Abbreviation, either at population or individual level; more frequently used notes were not shorter in length. However, as repertoire size in Java sparrows is small, we expect our power to detect Zipfs Law of Abbreviation to be weak. Whilst there may be some limitations in applying linguistic laws derived from human language to birdsong, especially Zipfs Law of Abbreviation, these laws may still provide insights into animal and human communication systems.