A groundbreaking study published on August 13, 2025, in the journal PLOS Computational Biology has revealed that bird vocalizations exhibit subtle patterns that mirror fundamental rules of human language. Researchers from the University of Manchester, in collaboration with Chester Zoo, identified tendencies in birdsong that align with Zipf's Law of Abbreviation (ZLA). This principle, well-established in human communication, suggests that frequently used words or sounds are typically shorter, a phenomenon attributed to the "principle of least effort" for enhanced communication efficiency.
While humans shorten words like "television" to "TV," the implications of such abbreviations in birdsong can be more significant. For instance, specific pitches in bird calls can convey a male's quality to females, with harder-to-produce notes often indicating better physical condition. Altering these crucial notes could lead to misinterpretations in mate selection.
The research team developed a novel analytical method using an R package called ZLAvian. This tool was employed to analyze bird songs from 11 populations across seven species, sourced from the Bird-DB database. The findings indicated a general inclination for birds to favor shorter sounds, though only one of the eleven analyzed populations demonstrated strong adherence to the ZLA pattern. The overall tendency for shorter sounds was notably weaker than observed in human language.
This area of research builds upon previous observations. Over three decades ago, Jack P. Hailman noted that black-capped chickadees frequently produced short call sequences more often than longer ones, though not strictly in accordance with ZLA. More recent studies have yielded mixed results, with some finding no evidence of ZLA in species like common ravens, while others have detected it in species such as African penguins and wild house finches.
The inconsistency of ZLA in avian communication may be due to the significant impact even minor changes in bird calls can have on their meaning, unlike the more flexible nature of human word shortening. While the study identified faint patterns in some bird populations, the consistency did not match that of human language, suggesting that if ZLA is present in birdsong, its application is far less stable.
The researchers concluded that if ZLA exists in birds, the patterns are significantly weaker and less consistent than those found in human language. Future research, utilizing larger datasets and broader species sampling, is essential to definitively ascertain whether this linguistic law applies to avian communication. The collaboration between the University of Manchester and Chester Zoo highlights a growing interest in understanding the intricate ways animals communicate, with the ZLAvian tool aiming to facilitate further exploration in this field and potentially in other animal communication systems.